Contrary to the popular belief, determinism has nothing to do with this. It has to do with the physics of our universe being causally closed. If it is (deterministic or random), then there can be no objective morality, or as 180 puts it:Is determinism true? How can we know for sure? — Truth Seeker
:100:There cannot be a vantage point for us outside of this causal nexus to differentiate right or wrong about assigning "actual moral culpability — 180 Proof
That's the common mistake. Determinism (or any closed physics) means that one cannot be held objectively culpable, which is very different from being held culpable.I don't take it for granted that determinism means you shouldn't hold someone culpable. — flannel jesus
The weather is closer. Fluid dynamics of a system in stable state (say water moving through a pipe, dam spillway) needs a description of that state, a calculus task. If it is dynamic (simulation of water waves), then it's more complicated, closer to the weather.couldn't one adopt the kind of approach that the weather forecasters (and, I believe, physicists trying to work out fluid dynamics, which is probably the same problem) have adopted? — Ludwig V
The entire paper is one hypothesis. There are not more that I am aware of.Comment - this possibility high-lights for me a question about Bostrom's first two hypotheses.
I posted his definition of 'posthuman', which is, in short, a level of technology capable of running the numbers he underestimates, and far worse, capable of simulating a posthuman set of machines doing similar simulations.That would require us to define what is meant by "post-human" and "extinction".
There you go. You seem to see both routes. The third path is extinction, or simple permanent loss of technology.Then we would have to deal with the difference between two different possibilities. We may go extinct and be replaced (or ousted) by some other form of life or we may evolve into something else (and replace or oust our evolutionary predecessors).
What two possibilitie? Humans that evolve into something we'd not consider human by today's standard? Many species do that all the time. Other possibility is 'ousted' as you put it. Our biological line is severed, as happens to nearly all biological lines given time.Given that inheritance is not exact copy and the feed-back loop of survival to reproduction works on us just as surely as on everything else, can we exactly define the difference between these two possibilities?
Good example. There are no dinosaurs (which, unlike humans, is a collection of species). The vast majority of those species were simply ousted. They have no descendants. But some do, and the alligators and birds are their descendants. They are not dinosaurs because none of them is sexually compatible with any species that was around when the asteroid hit. They are postdinosaur.They say that birds evolved from dinosaurs, and that mammals took over as dominant species from dinosaurs.
It depends on the species, or the individual. Mom has 2 kids. One of those has children of his own, and the other is ousted, a terminal point in the family tree.Which possibility was realized for dinosaurs?
Prediction of what? A simulation of history makes no predictions. A simulation of the future is needed for that, hence the weather predictors.Another problem. Given that a feed-back loop is at work on these phenomena, can prediction ever be reliable?
You really need to tell me what these hypotheses are, because I know of only the one. Two if you count the VR suggestion, but that doesn't come from Bostrom. i know of several that support a VR view, but none that has attempted a formal hypothesis around it.The third hypothesis suffers, for me
It the second possibility. He says one of the three must be true. It's not a list of three premises.The second premise - any posthuman civilization is extremely unlikely to run a significant number of simulations of their evolutionary history (or variations thereof) - seems obviously true to me. — wonderer1
If it is simulating at the particle level, yes. I can run an easy simulation of the planetary motions without simulating each bit. Each planet/moon/asteroid can effectively be treated as a point object, at least until they collide.The simulator would need to consist of more particles than the system which is being simulated.
Yes, and Bostrom claims several levels of depth, meaning the simulation is simulating the machines doing simulations.That's a rather fundamental problem. In practice, only things that are simpler than the simulator (or things treated simplistically) can be simulated.
Yes. If the goal was to simulate consciousness, they'd probably do one person, or a small isolated community (a closed system). And it wouldn't be a simulation of anybody real, but rather just a learning tool to show that a simulated person behaves like we do. If it worked, it would be a big blow to the dualists, but I'm sure they'd find a way to explain the results away.It seems to me that the person who would seek to disprove the second premise would need to prove that consciousness can arise in a simulation of something much more simplistic than the world we find ourselves in,
Posthuman is defined here:This paper argues that at least one of the following propositions is true:
(1) the human species is very likely to go extinct before reaching a “posthuman” stage;
(2) any posthuman civilization is extremely unlikely to run a significant number of simulations of their evolutionary history (or variations thereof);
(3) we are almost certainly living in a computer simulation. It follows that the belief that there is a significant chance that we will one day become posthumans who run ancestor‐simulations is false, unless we are currently living in a simulation. A number of other consequences of this result are also discussed. — BostromSimHypothesis
The trichotomy is reasonable, but worded in a misleading way. Point 1 makes it sound like this preposterous posthuman state is somehow inevitable if the human race doesn't meet an untimely demise along the way. This is nonsense since the posthuman state described is totally unreasonable, and human technology seems heavily dependent on non-renewable resources upon which this gilded age depends.The simulation argument works equally well for those who think that it will take hundreds of thousands of years to reach a “posthuman” stage of civilization, where humankind has acquired most of the technological capabilities that one can currently show to be consistent with physical laws and with material and energy constraints. — BostromSimHypothesis
Yes. That's Bostrom's whole point. He says we're probably all simulated, but it's based on the anthropic reasoning above, which makes many many unreasonable assumptions.So I have to imagine myself as being a sim and not knowing it? — Ludwig V
In that sense, the two are similar. Also, quite often, in both VR and a true sim, solipsism is true, but you know it because there are clues. We here are envisioning a scenario where the simulated reality is good enough that those clues get harder and harder to find.Regarding the question "are we in a simulation?" I interpret this as similar to "is solipsism true?" It's impossible to prove one way or another, but nevertheless - it's rational to believe we are not. — Relativist
Cool. I wasn't aware. Nice controlled test, and kind of pre-chat-bot, which is maybe a good thing. I wonder how trained the judges were; where was the focus of their questioning? To pass today with tools like chatGTP around, you'd have to dumb down the machine answers since it 'knows' more than any human, even if the majority of what it knows is wrong.Regarding the Turing test: it has been passed - to a degree.
It would seem fairly easy to pretend to be an unintelligent machine, but I presume these people were not attempting to appear nonhuman.Conversely, humans have "failed" the Turing test (https://www.nbcnews.com/news/amp/ncna163206) -- observers inferred that a human's responses were not humans.
Agree. The game playing AI does all that, even if it is confined to game playing. Early chess or go playing machines were like self-driving cars, programmed by the experts, using the best known strategies. Then they came up with a general AI (like AlphaZero) that wasn't programmed at all to play anything specific. There was only a way to convey the rules of the game to it, and it would learn on its own from there. After a few days of practice, it could beat anybody and any of the specifically programmed machines. That definitely meets all your criteria.Regarding "true" AI: IMO, it would entail a machine engaging in thoughts, learning as we do, processing information as we do, and producing novel "ideas" as we do.
Totally agree. Progress by imitation has its limits, but since a computer is not a human, to pass a Turing test it will always have to pretend to be something it isn't, which is hard to do even well after it has surpassed us in intelligence.Progress would not be measured by fooling people, but by showing there are processes that work like our brains do.
That is more relevant to this topic. To demonstrate how our brains work, you (probably) have to simulate it. To simulate it, you need to give it state and an environment (all this was brought up in prior posts). The state in particular is not exacty something you can make up. It needs to have grown that way through experience, which means a quick sim won't do. You have to start it from well before birth and run this really complicated simulation through at least years of life, providing it with a convincing environment all the while. Tall order. It would presumably take centuries for a single test to run, during which the hardware on which it is running will be obsoleted multiple timesBenefits include confirming our theories about some of the ways our brains work.
Then the test is invalid, I agree. If you click the link about the test being passed, the judges did not know which conversations were machines and which were people. They did know that there were five of each. Everybody (judges, machines, human subjects) knew it was a test.My argument is that if one starts the Turing test by specifying that the subject is a machine — Ludwig V
The Turing test was never intended as a test of consciousness.That's why the attempt to distinguish between the two on the basis of empirical evidence (Turing test) is hopeless.
True. Machines can detect skin cancer better than any human, and that's worth paying for (but there's probably a free app). In my case, the non-doctor tech that saw me googled my symptoms and read back to be verbatim the same information google gave me at home, but leaving off the part where it said "see your doctor if you have these symptoms". Obviously no actual doctor was consulted.But it might turn out that the machine is more successful than human beings at [medical diagnosis]
A 3 year old can imitate giving a diagnosis. Its how daddy gets covered by 20 bandaids. And if a machine can give a diagnosis (they can), then why would they have to imitate the ability that they actually have?I think that a machine can diagnose some medical conditions. Whether it can imitate diagnosing any medical conditions is not at all clear to me.
A few are false positives, which are often confirmed by a simple PM to them. The bots don't hold conversations, but rather give single replies to a question, and no more. Short, and often correct but obvious and not particularly helpful. If you reply to a bot-post, the bot will probably not notice it.Do you get confirmation about whether your "spots" are correct or not?
No more than is a tape recorder. Parrots don't pass a Turing test.Parrots imitate talking. Are they smarter than human beings?
In the Simulation Hypothesis, we are the simulated people, the ones inside the system. Do not confuse this with the VR hypothesis where the people are real and only their experience is artificial. Read the OP if you don't get this distinction.I thought you said that there were people inside the system. Now I'm really confused.
Indeed. I dragged in Relativist since the topic of Turing test came up, and he suggests that the test is insufficient to determine intelligence.I think that you are not talking about the same question as Relativist. (See below). — Ludwig V
Here again, the quoted comment concerns the Turing test, not the simulation hypothesis.And if a machine passes the test (it's a text test, so there's no robot body that also has to be convincing), then it exhibits intelligent behavior. The test is not too weak.
— noAxioms
Here, you are positing that you are starting with a machine. In that case, the question is whether the behaviour is really intelligent or merely seems to be intelligent. — Ludwig V
The Turning test is not a test for either of those. There's not even a test that can tell if your neighbor is conscious/sentient. If there was, much of the p-zombie argument would be immediately settled by some empirical test. The whole point of the term 'conscious' is that it is always defined in such a way that is immune from empirical evidence.even if the response was intelligent, it does not follow that the machine is conscious or sentient. — Ludwig V
The question is simple. I am communicating with some unknown entity via text messages, much like we do on this forum. The question is, is that with which I am communicating a human or not?The fundamental point is whether we can even formulate the question without begging it.
In a text conversation, yes. That's pretty hard to do, and we're not there yet.The Turing Test is passed by fooling people into believing there's a human giving responses in a conversation. — Relativist
Well, one of the ideas is to go outside those topics. I mean, none of the chat bots have long term memory, so one of their traits is that they don't ask any questions of their own since they cannot learn. I suppose clarification requests of questions posed to it might count as asking something.This is feasible today at least within a limited range of conversation topics.
You claimed the test is too weak. I claim otherwise. If it passes, it has long since surpassed us in intelligence. As a test of human-level intelligence, it is more than enough.What more are you looking for?
It's not empathy, but it very much is expressing empathy. People are also quite capable of expressing empathy where there is no actual empathy, such as the politicians that send their 'thoughts and prayers' to mass-shooting families, but do nothing about the problem.a computer can produce words that sound like it's expressing empathy - but it actually is not.
In a VR, yes, exactly that. People are real, and are fed experience of a simulated reality. Every video RPG does this.You are positing that it is people who are "in" the sim - i.e. (I assume) being fed the data. — Ludwig V
No. If you can do that, you very much are aware of the creator/creation status. It would be like talking to a god. In a VR, you can talk to the other players, and you can talk to the NPCs if the NPCs have enough intelligence to talk, but you can't talk to anybody outside the simulated universe.Plus, if I've understood you, you are positing that the subjects cannot communicate with whatever is running the sim
Nothing like dreaming.So how does this question differ from the brain in a vat, from Descartes' demon or from the supposed possibility that we are all dreaming? — Ludwig V
We are not bats. It's not about what it's like to be something we're not. We know what it is like to be a human. The question is, how might we (being the subject of simulation) detect that fact?So how does this topic differ from the question what it's like to be a bat?
Bostrom is half the story. Most popular fictions depict VR, not a sim. Matrix is a good example of a VR, however implausible.I'm afraid I didn't realize what the philosophical background is (essentially, Bostrom).
I didn't posit no ways ot testing. But depending on the quality of the simulation, it might get difficult. The best test is probably to recognize that there must be limits, and to test those limits.I don't find the question interesting, because if we posit that there is no way of telling, then there is no way of telling.
The 'can a computer think' topic was sort of about that. I suppose we could copy our own design and build an actual biological human, but in something other than by the normal way. Anything else is going to be trivially detectable. Not sure how that 'built' person would get loaded with experience. It's not like you can just upload software to a human. Doesn't work that way.The interesting question is under what circumstances we would accept that something we designed and built is a conscious being, i.e. a (non-human) person.
There is mention of the Turing test in earlier posts here. Passing it with a simulation is doing it the hard way. We're getting close to something that can pass the test now, but nowhere close to actually simulating the way a human does it. Perhaps you, like Ludwig here, mean 'imitation', which anything that passes the Turing test is doing by definition.The Turing Test is too weak, because it can be passed with a simulation. Simulating intelligent behavior is not actually behaving intelligently. — Relativist
Pain is not evil. I'd never want to change myself to be immune from pain. It serves an important purpose, and not an evil one.This is the traditional problem of evil. — Ludwig V
A statue, puppet, or a speaker blaring bird-of-prey noises to scare away geese, or a wooden duck lure, are all imitations/mimicry.I wish I knew what the difference is between a simulation and an imitation, a simulation and a mimicry, a simulation and an analogy, and a simulation and a model.
Remember, we're not worrying about what those running the simulation are calling the simulated things. We're supposing that we are the subjects here, the ones being simulated, and we (and only we) call ourselves human beings or people. That's the only definition that matters.I describe human beings, in contexts like this, as our paradigm of a person. — Ludwig V
That's kind of like suggesting that God is unethical to have created a universe that has beings that feel bad, and yes, there are those that suggest exactly that.I have to say, if these beings are to be conscious, I wish you luck in getting your project through your research ethics committee.
I wanted a universe that is simulated, instead of being instantiated in some other way. I do suppose that the simulated universe is a part of the container universe, but it's still a separate universe. That's questionable if it's an open simulation, but not all of them are. Much depends on the goal of running the simulation. Bostrom actually posits what that purpose would be, even if it is a totally naive one.My question now, is why not just talk about people living in a different universe?
It is the same universe as we are, because I posit that we are the simulated ones. How would be tell if that were true? The topic isn't about how to run a sim. The topic is about what it's like to be one.the sims you are describing are clearly in the same universe as we are.
There are definitely war elements in both, but that makes it more an analogy than a simulation. The do run simulations of war all the time, pretty much continuously. Yay cold war. Those simulations don't simulate the consciousness of anybody, and I don't think they even have people beyond statistical counts.Talking of sims, do you regard chess or (American) football as a simulation of war?
It is a parallel process, yes. Per relativity, simultaneous is an ambiguous term for events, and no, nothing in a any physical system requires spatially separated components of any process to be simultaneous in any frame. Per the principle of locality, one cannot depend on the other (they are outside each other's causal light cone), and thus the interactions can be simulated in any order, serially.I know human consciousness is a fairly hotly contested issue. But does anyone disagree that it involves multiple processes taking place simultaneously? — Patterner
Granted, but there's no need to, per the above comment. Any such transactions can be computed in any order without altering the outcome. Per the principle of locality, no spatially extended process can have a requirement of simultaneous operation.If we agreed that a process can take place in the scenario you're describing, you cannot write multiple things simultaneously.
On the contrary, time in the simulation has nothing to do with time for the guy with the pencil. Our pencil guy can set everything aside for a year and get back to it later. The simulated guy will not notice. No doubt each transaction will have a location/timestamp, and there's nothing preventing multiple transactions (all the transactions in a single iteration of the data) from having the same recorded timestamp. That is pretty much how simulations are done. Here is the state at time X, and then it uses that state to compute the next state at X+<increment> where the increment might be a microsecond or something. It might take a minute for a machine to simulate all the transactions to generate the next state. It might take the pencil guy several lifetimes to do the same thing, so we're going to need that society to train his replacements each time he retires.At no time, in no sense, is everything needed for human consciousness happening at the same time in the paper and pencil scenario.
At risk of opening a can of worms, how does 'modern physics' come into it?
I joined this and other forums to find out how the prominent philosophers (the ones you learn of in class) dealt with modern physics (narrowing the search to recent ones of course) and found that for the most part, they either didn't know their physics, or didn't care about it.
So I learned physics, or at least the parts of it relevant to the subjects I cared about.
Relativity threw significant doubt to Newtonian absolutism where there was one preferred frame and time was posited to be something that flows or progresses, that there was a preferred moment in time, and the universe was static, and either infinite age or somehow set in motion from some initial state at some point. Much of religious myths (especially the creation parts) requires the universe to be contained by time instead of the other way around, and this did not become apparent until about 110 years ago. The universe having a finite age is about a century old, and some religious teachings did at least bend with that one and put the creation event there.
Quantum mechanics really threw a spanner into the gears with suggestions that ontology might work backwards (that existence depends on interaction with future things), that identity of anything (electrons, rocks, people) is not at all persistent and thus I am not the same I as a second ago.
One can of course pick an interpretation consistent with your preferences and avoid the implications of the ones you don't like, but if doubt is to be eradicated, all the alternative interpretations contradicting the thing of which you are certain must be falsified.
And who knows what else might get discovered. Nobody saw QM coming, so all these people who held certain beliefs with certainty found themselves to be wrong or at least potentially wrong. So a declaration of 100% certainty is irrational. I mean, my certainty rests on the sum of two numbers (a pair of arbitrary real numbers say) being exactly one other real number, always and anywhere. I don't significantly doubt that, but I still question it. What if it's only a property of this universe that such a sum comes to that one solution and not a different one elsewhere?
— Wayfarer
Indeed it isn't, but the assumption is implicit. It's too obvious to bother calling out explicitly, or at least it was obvious until ~50 years ago.Persistence of self-identity over time is not discussed in Descartes
Your opinion. The opinion of others may vary.Beings are not objects or things
I knew what you meant, even if Wayfarer chose to reply to what you said instead of what you meant.I was thinking of philosophical zombies — Ludwig V
The Turing test (The closest 'Turing Hypothesis gets is the Chuch-Turing thesis, concerning what is computable, and is oddly relevant below) is an intelligence test for when a machine's written behavior is indistinguishable from that of a human. The large language models are getting close, and the easy way to tell the difference is to not ask them questions with factual answers. They also are not designed to pass the Turing test, so all one has to do is ask it what it is.My point is that there is no easy and clear way to state what the Turing hypothesis is trying to articulate.
A simulated person would be a person, just in a different universe (the simulated one). It's likely quite a small universe. You seem to define 'person' as a human in this universe, and no, the simulated person would not be that.Suppose that these simulated people are conscious (as they would be if the simulations were sufficiently fine-grained and if a certain quite widely accepted position in the philosophy of mind is correct).
For me, a conscious being is a person and a simulated person is not a person, so this confuses me. Can you perhaps clarify?
And it was already used in somebody else's reply.why isn't 'dubit' a word? It ought to be.
— noAxioms
Well, since you have now used it, and I understand it (roughly, I think), it is a word now.
Not sure what the term 'active medium' means. Googling it didn't help. I can implement a Turing machine armed with nothing but paper and pencil. Per the Church-Turing Thesis mentioned by mistake above, that means I can do anything that is computable, including the running of the simulation.It seems to me you cannot simulate with paper and pencil, because it is not an active medium. — Patterner
But I am hitting 'run'. I wouldn't need the pencil if I didn't 'run' it.If you program everything necessary to simulate consciousness into a computer**, but never hit Run
There's a contradiction here. People is animal. A machine is not animal. But a machine can be people? That means a machine is animal and not animal.a person is a human being, i.e. an animal. ... Some physical structures are machines, and hence not animals, but I don't see why such structures cannot possibly constitute people. — Ludwig V
I think you are again envisioning imitation people, like Replicants. That's a very different thing than the simulation hypothesis which does not involve machines pretending to be people.But if they are to constitute people
No. The simulation is creating a biological person, not a machine person. Try to get that. Replicants are not grown from a zygote. A replicant can be trivially tested by an x-ray or just by sawing it in half, or so I suggest. Apparently in Blade runner, it was very hard to tell the difference, but that's also a fiction.So I think you are right to argue that some such process as this would be necessary to create a machine person.
That's right. Physics doesn't do spontaneous things (quantum mechanics excepted, which is a big problem if you want to simulate that). But classical physics isn't spontaneous, and yet spontaneity emerges from it, or at least the appearance of it. Anything in the simulation would have to behave just like that.Calculating is widely recognized as a rational activity.
Yet again, no computer is pretending to be a person, so it isn't a problem.To me, it makes no sense to deny that computers can calculate. The catch is that such rational activities are not sufficient to be recognized as a person.
Probably invalid in this case, and yes, I've decided that, but on weak grounds since I have never followed the argument from beginning to a preselected improbable conclusion.If you call it a rationalization, you have already decided the argument is invalid or unsound.
If the simulation is any good at all, and presuming monism, then yes, it would be painful to the subject in question. No, the computer running the sim would not feel pain, nor would the people responsible for the creation of the simulation, despite suggestions from Kastrup that they apparently should.Would a simulation of agonising pain be actually painful?
I didn't say that was the rationalization. I even accepted it since it was a reasonable statement in the absence of modern physics. It is him building on that foundation to his later conclusions that is the rationalization, which I clearly spelled out in my post.The logic of cogito ergo sum is neither rationalisation nor myth, it is the indubitable fact — Wayfarer
I agree that the logic presented is completely valid, but the premises are outrageous, and the conclusion is only as sound as those premises.That it is another universe, is one of hte ridiculous premises required for its probability to be an effective argument. This is what I'm getting - on it's face, its mathematically almost certain we are in a simulation set up by future generations. — AmadeusD
I don't take the argument seriously due to the faulty premises. I see no reason to actually suspect that I am a product of simulation, but I also don't rule it out, nor would I personally find it unnerving to actually find evidence that such is the case.But the invocations required to actually, practically, in real life take that seriously are unnerving to say the least, and perhaps the sign one is not being honest with themself.. if the theory convinces one.
OK. I admit to not reading the whole thing because I was only trying to point out similarities in the issues of BiV and VR, which are often aligned.But you did not go further into the argument. That is the opening argument for the BIV. But Putnam continues on to counter-argue that premises or claims above are necessarily false. If you're a BIV then to say "I am a brain in a vat" is false because you wouldn't be referring to a brain and to a vat. There's no reference at all! There is no causal link to make the argument sound. — L'éléphant
I don't follow that. If it says (without evidence) that it is a BiV, then the utterance is true if that is indeed the fact. It's just not something justifiable, at least not if the lies being fed to it are quality lies. So it isn't knowledge, but not all utterances are necessarily false. What about 2+2=4? Is that also one of the lies?If it is indeed just a black-box or non-human mind being fed false information, anything that comes out of its mouth referring to anything about the physical world is false. — L'éléphant
OK, I haven't brought this up, but if it is a true sim (not a VR), the sim is computing the values of a mathematical structure (this universe), which is sort of presuming something like Tegmark's MUH.The simulation hypothesis is a pitfall -- it looks attractive because it allows us to make arguments like "how do you prove we're not in a doll house?" but we fail to recognize the contradiction of the utterance.
Several differences. The sim is run at some finite level of detail. Does it have mitochondria? Depends on the level of detail, if it matters to the entity running the sim. The sim probably cannot run at the quantum level, and the real zygote does, and even deeper if there is a deeper.You said you would start the sim as a zygote. I am asking: what is the difference between this zygote and a zygote in reality? — NotAristotle
Yes, that. You don't need to pre-load the simulated thing with memory of a past consistent with the fake initial state of the simulation. That's the problem we're trying to get around. Don't know why you find this problematic. The system simulated then grows up into a conscious human with real memories of its upbringing, not fake memories planted by an initial state that probably doesn't know how memories are stored. The whole point of the sim after all is to learn these things.Or is the zygote you are postulating a mere simulation of a zygote?
And here I go doing exactly that, not denying it, but having doubts about it to the point of abandoning the realism it fails to explicitly posit.Per Descartes, I hold that the fact of one's own existence, that one is a subject of experience, is apodictic, it cannot plausibly denied. — Wayfarer
I do think there are ways, but most of the posters are using fallacious methods to justify their assertions.So, you don't think there's any criterion by which we can discern the difference. — Wayfarer
The possibility that I am a real being already is contingent on the definition of 'real', and not being a realist, perhaps my not believing that has nothing to do with any suspicion of being a product of a simulation.You admit the possibility that you're not actually a real being. — Wayfarer
Unclear on the question. The difference between reality (which doesn't supervene on something higher) and the sim (which does) is just that. Reality is supposedly a closed system, and the simulation (either kind) is not, and there is one of the places to look for empirical differences between the two.What is the difference between the simulation and reality if you are constructing "simulated people" based on the same historical states that result in non-simulated people? If the physicalness of both systems is identical in all respects, what is the difference? — NotAristotle
Bostrom assumes otherwise, but whatever realm is running his simulation doesn't need to be a universe like our own.I agree, generally. The paper, on it's face, is fairly convincing but it requires such a ridiculous set of premises (similar to the Fermi Paradox) that it doesn't seem all that apt to the Universe we actually inhabit. — AmadeusD
If you or Kastrup expect a kidney in one universe to produce urine in another, then you don't really know what a simulation does.I’m sure simulations of kidney functions, like other organic functions, may be extremely useful for medical research and pharmacology, without literally producing urine. — Wayfarer
But the question asked is how we might know (and not just suspect) that we are not the product of a simulation. A detailed simulation of you would likely deny his own unreality (as you use the word here), and would also deny that his consciousness is the product of his underlying physics. If he does this, he would be wrong about both. I'm not sure what you'd expect that simulation to yield.That’s the point - simulations may be useful and accurate, but they’re still simulations, not real things.
The simulation needs to provide an initial state that provides that history. History is, after all, just state. Hence my suggestion of starting the sim of a human as a zygote since there is no need to provide it with prior experience. But then you have to simulate years of experience to give it that history, but at least you don't need to presume what the mature brain state might be.Regarding your objection re: physicalism. The problem with conscious people within/part of a simulation has to do, in my opinion, with the historical necessities of consciousness. That is to say a simulated person does not have the requisite history to be conscious. — NotAristotle
It has to start somewhere, so the womb would be outside the system, an imitation womb, empirically (to the child) indistinguishable from a real mother, in every way. I suppose the placenta would be included in the system since it is, after all, the child and not the mother, but when it is severed, the sim needs to remember which half to keep as part of the system.and someone alive must come from someone else who is alive
To a simulation of low level physics, they pretty much are the exact same category, and both have the same problem of needing to exert some kind of effort to keep track of what is the system and what isn't, a problem that real physics doesn't have since it operates on a closed system.People and inanimate objects are not in the same category — Ludwig V
Similarly, a person (and not a brain) is what is conscious. Not even that, because an environment is also needed.What keeps the house warm, (not too hot and not too cold) is the entire system including the water, the pump and the radiators, with its feedback loops and not any one component.
Irrationality is required for consciousness? A computer is rational? I question both. Deterministic is not not rationality. I do agree that irrationality is a trait of any living creature, and a necessary one.A computer is arguably more like a conscious being, that it is probably too rational to count as one.
Any sim would be distinguishable from a dream state.If that's the point, we don't need the theory. We all experience dreams from time to time. And we know how to tell the difference.
Sometimes. One is often reft of rational thought while dreaming, but not always. I can tell sometimes, and react to knowing so.But we can't tell the difference while we are dreaming.
Yes, Wayfarer just below quotes Kastrup suggesting exactly that.The weather event would need to be wet and windy, and not just appear to be wet and windy." — bongo fury
It would be a piss-poor kidney simulation (pun very intended) if it didn't.Bernardo Kastrup says you can get a computer to run an exquisitely-detailed simulation of kidney function, but you wouldn't expect it to urinate. — Wayfarer
Well, the Sim hypothesis (all versions) as how we might know we are or are not in a sim or VR. You're speaking of a VR in this case. Your memories define who you are, and if those are totally wiped, it's somebody else in the VR, not the person who entered it.It doesn't have to be "at any time", it can just be at the start. And presumably a baby could be hooked up to the machine anyway, without any concern for their memories, no? — flannel jesus
I echo NotAristotle's sentiments. If the guy knows he is in a simulation, he also knows that the virtue he is practicing is wasted, benefiting nothing but shadows of people. Knowing this, he happiness would hardly be maximized. The experience machine, to maximize his happiness, would in short order exit him from it to allow him to practice actual virtue that benefits actual people.Might such a machine invariably force users to voluntarily exit the machine (provided exit is possible)? — Count Timothy von Icarus
This would be a violation of the premise, that only the inputs and outputs are artificial, and the experiencing entity itself is left to itself. If you posit that even your memories are open to direct manipulation at any time, then you end up in the Boltzmann Brain scenario, where,such a hypothesis, as Carroll put it, "cannot simultaneously be true and justifiably believed".I don't think so. If someone made such a machine, that someone could know enough about a brain to manipulate memories too. They can manipulate your entire experience of your world, why not your memory? — flannel jesus
The one (at a time) person operating the pencil and paper was implied. Also not explicitly missing is a society to breed, train, feed, and otherwise support the efforts of the series of people doing the primary task. A big part of that support is replacement of paper/parchment as it decay into unreadability before it is actuall needed as input for a subsequent step. But the computer also needs to do this, and a lot more frequently than every few centuries or so. Computer memory rots and needs to be refreshed a few hundred times per second.A pencil is not an information processing system. A pencil may be part of an information processing system which includes a person and a pencil and piece of paper, but the brain of the person is playing the key role in whatever information processing occurs. — wonderer1
That's right. As you point out it would need a person operating the pencil, which, based on your protest above, is something you feel needs to be explicitly specified.To answer your question, a pencil can't process the video file found here.
Well, to quote the BiV IEP page, very close to the top:I disagree with this. In the BIV, the brain is a given. That is, human brain. — L'éléphant
https://iep.utm.edu/brain-in-a-vat-argument/#:~:text=The%20Brain%20in%20a%20Vat%20thought%2Dexperiment%20is%20most%20commonly,experiences%20of%20the%20outside%20world.Or, to put it in terms of knowledge claims, we can construct the following skeptical argument. Let “P” stand for any belief or claim about the external world, say, that snow is white.
[1] If I know that P, then I know that I am not a brain in a vat
[2] I do not know that I am not a brain in a vat
[3] Thus, I do not know that P. — iep BiV
Yes, that's exactly the point, and yet most VR discussions (say the thing that Musk suggests is almost certainly true) fail to be skeptical about his true nature, something for which he has pretty much zero empirical evidence if his skepticism is true.Because the point of the theory is skepticism
Why wouldn't you then remember being hooked up to the machine? You only have memories of a world where such a machine is not possible (yet), so an actual transition from reality to VR is not plausible.If I could experience the real world, then be hooked up to a machine that simulates the same thing I have experienced, seamlessly, that I would not be able to tell the difference, then theory has made its point.
And did the nay-sayers actually come up with a reason why it could not? The only reason I can think of is that of dualism: Total denial that consciousness can be a physical process at all. It needs magic to fill what are seen as gaps, and a simulation (both computer or paper) for some reason is denied access to that same magic.I remember raging arguments at the International Skeptics Society years ago about whether enough monks writing down 1's and 0's could simulate consciousness, like the guy in the comic I posted moving rocks around and simulating this universe. — RogueAI
Same question then: What information can a computer possibly process that a pencil cannot? Time of computation seems to be the only difference, and time of computation is not a factor at all with the Sim hypothesis, even if it is absolutely critical to the VR hypothesis.A computer can process information in ways that a pencil cannot. Why think consciousness can exist without the occurrence of information processing? — wonderer1
Picture 'reality' R0 as the trunk of a tree. It has 9 boughs (S1-S9) coming out of it, the simulations being run on R. Each of those has 10 branches, labeled S10-S99. Those each in turn have 10 sticks (next level simulations (S100-S999), Then the twigs (S1000-S9999) and the leaves (S10000-S99999). Every one of those simulation has say 10 billion people in it, so a given person is likely to be simulated (all except the ones in R0), and most of those (90%) find themselves in the leaves, the non-posthuman state as defined by Bostrom. So finding yourself in a state where such simulations are not possible is most likely. And this is presuming only 10 simulations per world, whereas Bostrom posits far more, so the numbers get even more silly.It is unclear to me why there would be more leaf worlds, could you spell that out for me? — NotAristotle
A description of a running process is a map. The process itself is not.A running process isn't just a succession of maps? — bongo fury
It would need to simulate the NPC down to the biochemical level. The NPC would need to be conscious to believe anything, and not just appear to believe stuff. Heck, Elon Musk 'appears' to believe he's in a VR (as a player presumably, not an NPC), but it is questionable if he actually holds this belief. Ditto for a few other notable celebrities that make heavy claims but seem to have ulterior motives.Do you mean that some part of the computer running the game would need the detail? — bongo fury
An AI is needed to make a convincing NPC that doesn't do its own thinking. It is far more efficient for the actions to come from an AI than it is to actually simulate the character's thoughts and other processes. A pure closed simulation (Sim or VR) needs no AI at all, just brute capacity. No current game has any character do its own thinking, and the NPC are really obviously an NPC since barely any processing power is budgeted to doing the AI better. It's getting better, but has a long way to go before the line between players and NPCs begins to fade.Then you're talking about an AI
Heck no. A game need only simulate my sensory stream, nothing else. There's no reason to make the characters appear to ponder about what their nature is.Or do you mean that a fictional character described and depicted in the game would need the detail?
I've seen the xkcd thing, yes. I'm not the first to see it. There's lots of references to 1D and 2D simulations in that, but how else are you going to depict it in a comic?Have you ever seen this? — RogueAI
That's pretty much Bostrom's argument, a sort of anthropic reasoned hypothesis that demonstrates a complete ignorance of how simulations work.I think I have heard it said that if a future people decided to make a simulation, they would make A LOT of such simulations. And these simulations would be nested -- simulations within simulations. — NotAristotle
That was one of the counterarguments that I think itself fails to hold much water. If each simulation runs several internal simulations, the leaf ones (us) would be exponentially more in number than the base levels. Of course this exponential simulations that are simulating other machines running simulations is a big part of the reason the premises fall apart.If there are a huge number of simulations within simulations, that means only a small number of these simulations will be simulations that do not have a simulation that they are themselves running. But if we are living in a simulation, we must be living in one of the simulations that is not itself running a simulation. In that case, the odds that we are living in a simulation would be astronomically small.
Why not? I mean, if you deny that consciousness emerges from physical process, then it falls right out of the gate, but presuming physicalism, the simulated person wouldn't act correct if the simulation got the physics wrong.On the other hand, I do not think we would be conscious if we were "in" what you are calling an actual simulation.
How? Incredulity? I'm trying to gather actual evidence for both sides. Lots of people 'know' things for sure, and lots of what people 'know' contradicts what other people 'know'. Humans are quite good at being certain about things for which there is no hard evidence.In any case, I know I am not living in a simulation.
This is better worded. It's an extraordinary claim and it requires extraordinary evidence to be taken seriously. The various proponents seem to to use very fallacious arguments in an attempt to demonstrate that evidence.I won't seriously consider the possibility that I'm living in a simulation, or a simulation myself, or a Boltzman brain, or whatever else. — Patterner
That means that no observer can have knowledge of the workings of such a universe.A theory in which most observers are of the Boltzmann Brain type is ... unacceptable: ...
The issue is not that the existence of such observers is ruled out by data, but that the theories that predict them are cognitively unstable: they cannot simultaneously be true and justifiably believed. — SCarroll
I didn't say it did, any more than does the alternative view. The topic surely is discussed in more relevant topics on this forum or on SEP pages. It is a digression here. The Sim hypothesis presumes, as does the last 5 centuries of science, a form of physical monism. There's no hard problem to be solved. There's nothing 'experiencing' you first person.I am not familiar with any arguments for how physical processes provide an account of the first-person nature of consciousness. — Patterner
Well, if you simulating a collection of electronic switches (which a human is, in addition to a lot of other supporting hardware), and you consider that such a collection (the human) is conscious, then yes, the simulated thing will be conscious... that the thing simulated is conscious.
— noAxioms
Which is to say that a collection of electronic switches is conscious. — RogueAI
The model is perhaps a design of a simulation. The simulation itself is the execution of it, the running of code on a computer for instance being one way to implement it, but paper and pencil also suffices. A simulation is a running process, not just a map.So, a simulation as a description or theoretical model, distinct from any real or imaginary structure satisfying the description. — bongo fury
Gosh. This? — bongo fury
You both seem to balk at the paper/pencil thing, but what can a computer do that the pencil cannot? If you cannot answer that, then how is your denial of it justified?This is absurd. You're not going to be able to simulate a conscious person with paper and pencil. — RogueAI
The NPC in the computer game would need that amazing level of detail to actually believe stuff (like the fact that he's not being simulated), and not just appear (to an actual player) to believe stuff.A novel or a computer game can perfectly well describe or depict a conscious human that doesn't know he is being imagined, and it can equally well describe or depict a conscious being that does know. Detail is neither here nor there. — bongo fury
It simulates no mental processes at all. It answers on its own, not by simulating something that it is not. It is an imitation, not a simulation of anything.ChatGPT certainly simulates mental processes (or seems to. More about that in a second). — RogueAI
That of course depends on your definition of 'conscious'. Most of the opponents of machine consciousness simply refuse to use the word to describe a machine doing the same thing a human is doing.Do you think it might be conscious?
It probably means creating a map of brain neurons and synapses organization and running that in a dynamic simulation that not only follows neural activity (and input), but also simulates changes to the map, the creation/deletion of neural connections.Now, when you drill down on "simulate mental processes", what does that ultimately mean?
I don't think it takes very many, but to me, consciousness is a gradient, so the question is not if you're conscious, but how conscious. It is more of an on/off thing with a definition like Wayfarer uses, of having first person subjectivity or not. I don't really understand that since I don't see how an device with local sensory input doesn't have first person subjectivity.think that sounds like magic, but everyone else is taking it seriously, so you also have to take seriously the idea that it might not take a whole lot of switching operations to generate consciousness. — RogueAI
... that the thing simulated is conscious. The simulation itself is no more conscious than is real physics. As I said just above, a sufficiently good simulation of a bat would not know what it is like to be a bat, but the simulated bat would.So it seems that if we're going to take simulation theory seriously, we should be equally open to the idea that some of the simulations we're running now are conscious.
I suppose it would require one to identify a construct as a creature. One can I think implement a Turing machine in GoL, so one you have that, there's little it cannot do.Maybe some of the "creatures" in Conway's Game of Life are conscious. Why not?
The simulation hypothesis does not suggest that any physical planet (Earth) was created as an approximation of some design/model/real-planet. It is nothing but a hypothesis of something akin to software being run that computes subsequent states from prior states. A VR is a little simpler and more complicated than that because the subsequent states are computed not only from prior states, but also from external input. Sim is deterministic. VR is not.Surely the problem is the one frequently pointed out, with the word "simulate" being ambiguous between "describe or theoretically model" and "physically replicate or approximate". — bongo fury
That was very serious. Sim is simply a computation, and any computation that can be done by computer can also be done by pencil and paper, albeit a lot slower and a lot more wasteful of resources. But time is simply not an object. One might consume 50 sheets of paper and one pencil a day, and the only reason it wouldn't work is because Earth would die before you got very far in a simulation of something as complicated as a person in a room.So the question occurs, are you holding this
That means that yes, even the paper and pencil method, done to sufficient detail, would simulate a conscious human who would not obviously know he is being simulated.
— noAxioms
up for ridicule, or serious consideration?
For the last 5 centuries or so, science has operated under methodological naturalism which presumes exactly this, that everything has natural (physical) causes. Before that, it operated under rmethodological supernaturalism where supernatural (magic) was the cause of anything inexplicable, such as consciousness, the motion of the planets, etc. Presuming magic for the gaps contributed to keeping humanity in the dark ages. The other big cause was general illiteracy, but that continued until far more recently.I think [physical processes producing consciousness] sounds like magic, but everyone else is taking it seriously — RogueAI
No. If you miniturize the VR set (the device that feeds fake sensory input to you, and conveys your responses to the VR) to fit a frog, then a frog can enter the VR just like the human does.So if I miniaturized the AI hardware and grafted it into the frog, it becomes a simulation instead of a VR? — Ludwig V
From this world yes, but it isn't a simulation of this world.But it is an abstraction from the world in which Conway - and you and I - live.
I'm using 'world' in many ways. There's the world that we experience. If it's a simulation/VR, then there is another world running that simulation, upon which this world supervenes. Maybe that world also supervenes on an ever deeper world, and (as Bostrom hints), it is turtles all the way down.I thought we were using "world" in the first sense.
I would not say that. They are not 'simulations' as the word is being used in this topic. Those films (any film) are mere depictions of those fantasy worlds, not simulations of them.Well, I would say that those films are simulations of a fantasy scenario/world.
Good point, that VR need not involve deceit. One can use a VR setup to say control an avatar in some hostile environment. The military uses this quite a bit, but those are not simulations. Not all VR is a simulation, but this topic is only to discuss the ones that are. I cannot think of a VR into a simulated world that doesn't involve the deceit of making that simulated world appear real to the subject. It actually being real or not depends on your definition of 'real'.But the idea that VR might be used to deceive people itself presupposes that what is presented by the VR is not real. What might be more troublesome is a VR that re-presented the actual world around the wearer. Pointless...
No, but their reasoning made a nice counterexample to your assertion that other people are necessarily as real as yourself. In a VR, and even in a Sim, this isn't necessarily true. I enumerated three different kinds of people, each of which operates differently. I suppose I should give them names for easy reference.Are you an idealist?
Last I checked (which has been a while), they can do bugs, and even that is probably not a simulation of the whole bug, let alone an environment for it.If you're open to the possibility that consciousness could emerge from a computer simulation, are you also open to the idea that consciousness is already emerging in the simulations we're currently running? — RogueAI
Pretty much, yea. All the same arguments (pro and con) apply.This runs smack into the 'hard problem of consciousness', which is that no description of physical processes provides an account of the first-person nature of consciousness. — Wayfarer
Not sure what is being asked. I mean, what aspects of physical processes would, if absent, not in some way degrade the subjective experience?Which aspects of physical processes correspond with subjectivity? — Wayfarer
The idealists for one would disagree with this. Idealism tends to lead to solipsism, where only you are real and all the other humans are just your internal representations (ideals) of them. You've no hard evidence that they're as real as yourself. Of course, modern video games are terrible at displaying other people, and you can tell at once that they're fake. But we're assuming far better technology here where it takes more work to pick out the fakes.Clearly, we know that human beings are persons without knowing (in any detail) about their internal physics. — Ludwig V
'The same' means, in a Sim, that both you and the other thing (a frog say) are fully simulated at the same level, perhaps at the biochemical level. You and the frog both make your own decisions, not some AI trying to fool the subject by making a frog shape behave like a frog.One needs to specify that "the same" means here. — Ludwig V
Google it. Standard video game term for Non-Playing-Character. It typically refers to a person/creature in a game that isn't played by any actual player, They tend to be bad guys that you kill, or race against, or whatever. In the Sim scenario, it would be a person not actually conscious, but whose actions are controlled by an AI that makes it act realistically. In VR, NPC refers to any person not under virtual control, whether self or AI controlled.I'm sorry, what are NPCs?
Conway's Game-of-Life (GoL) is not in any way derived from the world in which we live, so there's a counterexample to that assertion.We can, of course construct, imaginary worlds and most of the time we don't bother to point out that they are always derived from the world we live in. — Ludwig V
Well yes, since there'd not be much point in simulating a car that crashes under different physics. The intent in that example is to find an optimal design based on the simulation results. Not so under GoL.As here, we know about real cars that really crash and what happens afterwards (roughly). That's the basis that enables us to construct and recognize simulations of them.
Those are not simulations. Heck, the physics of those worlds are both quite different than our own. The Hollywood guys are hardly paid to be realistic about such things."Star Trek" and "Star Wars" are extensions of that ability.
If it's good enough, then no, it would not be easily distinguished from a more real reality, especially since the lies are fed to you for all time. Unl[ike with a video game. you have no memory of entering the VR. Of course all our crude VR does it feed fake vision and sound effects to you. Not the rest. You can feel the headset you're wearing. But even then, sometimes you forget.... It's pretty creepy in some of the scary games.We know quite well what is VR and what is not, so it is clearly distinguishable from reality. — Ludwig V
Yes, that's the idea (one of them) under consideration here. How do you know it's false? Just asserting it false is beyond weak.Of course, we can frighten ourselves with the idea that a VR (In some unimaginably advanced form) could be used to deceive people;
Implausible too, but that's entertainment for you."Matrix" is one version of this.
The bit about imitation people (human-made constructs) is very relevant to the 'thinking computer' topic, and relevant only if not all people/creatures are conscious in the same way (a process running the same physics). The idea is preposterous at our current level of technology, so any imitation people would probably be of alien origin, something that cannot be ruled out. They'd not necessarily qualify as what we term a 'computer'.The "simulation hypothesis" is indeed quite different from the hypothesis that there are imitations of people around. — Ludwig V
OK, if not all the people are simulated the same, then the ones that are not (the NPC's) would be fake, not conscious, but controlled directly by some AI and not the brute implementation of physics that is the simulation itself. There has to be a line drawn somewhere between the simulated system and what's not the system. If it is a closed system, there need be no such line. A car crash simulation is essentially closed, but certain car parts are still simulated with greater detail than others.On the face of it, this looks like a generalization from "there are some fake. imitation, simulated people around" to "everything is a simulation". — Ludwig V
Under simulation hypothesis (both Sim and VR), the forgeries are any external input to a non-closed system. Bostrum posits a lot of them.On the contrary, a forgery can only be a forgery if there is such a thing as the real thing. — Ludwig V
Disagree. The car thing was my example: Simulation of a vehicle that has never existed. Our world could in theory be a simulation of a human word made up by something completely non-human, and perhaps not even a universe with say 3 spatial dimensions, or space at all for that matter. There need be no real thing. I personally run trivial simulations all the time of things that have no real counterpart. Any simple 1D-2D cellular automata qualifies.In all of these cases, there is always a question what is being imitated or forged or whatever. — Ludwig V
I hope to explore that question in this topic. For one, our physics has been proven non-classical, and thus cannot be simulated accurately with any classical Von-Neumann computer no matter how speedy or memory-laden. But that restriction doesn't necessarily apply to the unknown realm that is posited to be running said simulation. But it's good evidence that it isn't humans simulating themselves.What empirical evidence could possibly confirm or refute this? — Ludwig V
Sort of. Yes, they have a model. No, it isn't a model of something that exists. There isn't a 'real thing' to it.Fair enough. But in those [car crash] cases, it is clear what the simulation is a simulation of. — Ludwig V
The skull-vat view does not feed the mind a set of artificially generated lies. VR does.I'm afraid I don't have the time to respond in detail to what you say about actual simulation and virtual reality. Perhaps later. I'll just say that, so far as I can see, the BIV hypothesis either presupposes the existence of normal reality or describes all of us right now. (The skull is a vat.) — Ludwig V
He does seem to throw the resources around, yes. A lot of it presumes that Moore's law continues unabated for arbitrary more time, which is preposterous. We're already up against quantum resolution, and chip fabs requiring nearly maximum practical resources.Bostrom's speculation has always smelled grossly unparsimonious, to me. — wonderer1
OK, so I spent some time on that article, and apparently the Wigner's friend experiment is something completely different than what I've seen described under that name.I was just trying to paraphrase the Wikipedia article. — Michael
It doesn't. None of the interpretations are physical theory, but some of them are metaphysical interpretations of it.How can a physical theory say anything about metaphysics? — Benkei
— RogueAI
There is not. The live human will experience nothing out of the ordinary, and will experience not getting killed. The science is very clear about this. That certain philosophical stances might disagree with this seems to be a problem with the philosophical position, and not with science.ChatGPT]there's a philosophical and conceptual conundrum regarding what the human would experience or perceive during that time. —
If one presumes that consciousness arises from classical processes in the brain, then the answer is clear, but chatGPT apparently doesn';t see it. The conundrum only appears when different assumptions (woo) are made.ChatGPT]as consciousness typically arises from classical processes in the brain, which are not well-described by quantum mechanics. —
Ouch. So it says the human will not remember being in the closed box. Science says nothing of the sort.ChatGPT]Therefore, when the box is opened and the human is found to be alive, asking the human "what was it like to be in a superposition?" might not yield a meaningful answer. The human's subjective experience would likely begin at the moment of observation, just like our experience when waking up from a dreamless sleep or regaining consciousness after anesthesia. —
The cat is entangled with the particle state, so it, and the bottle, are all very much in superposition. Keep in mind that there's pretty much no actual way to do it with a cat. They've done it with macroscopic objects, but only by putting it in conditions under which no living thing would survive. The problem is the box. The box must be something that can hold a cat, and yet can prevent any information about the box contents from escaping. Maybe if the box is put in deep space and is surrounded by multiple shells of shielding, none touching the others.The cat isn't in a superposition the particle triggering the poison is. — Benkei
It was, because the outcome was considered absurd at the time, but no longer. Schrodinger also envisioned a simple iron box, which hardly works. But then, Copenhagen was the only interpretation around at the time, and it was an epistemological interpretation, and epistemologically, the cat state is simply unknown (indeterminate as you put it). But it turns out that one can perform an experiment to demonstrate the superposition of macroscopic states (this has been done), so the absurdity turns out to be reality.I believe Schrodinger's rhetorical point was to drive home the absurd nature of superposition with a life-size example. — Wayfarer
Yes, the OP describes Wigner's friend, but your summary doesn't. It has nothing to do with somebody holding a secret. It has to do with putting a human in the box. This is an attach against the Wigner interpretation, the only interpretation where humans play a significant role. Wigner himself abandoned the interpretation because it leads to solipsism.This is Wigner's friend.
Wigner observes John.
John measures a particle spin but doesn't tell Wigner the result.
From Wigner's perspective, is John in a superposition? — Michael
You should have linked the threadWe had a long thread on Wigner's friend already — Benkei
According to objective collapse theories, superpositions are destroyed spontaneously (irrespective of external observation) when some objective physical threshold (of time, mass, temperature, irreversibility, etc.) is reached.
Only an epistemological interpretation (old Copenhagen) would say this. Pretty much all interpretations since are metaphysical interpretations with describe what is, not what any particular observer knows. Humans play no special role in wave function collapse, except in that solipsistic Wigner interpretation.in any case is not a state of being but a consequence of epistomological limitations of knowledge of a given system. — Benkei
Not sure what you mean by iteration, or 'permitted'. It's a loop, an instance of reverse causality. It's one loop in our example, and it just is, per non-presentist framing of the situation. There is no 'changing of the past'. I gave an example of a worldline that traverses the loop twice, so that might constitute iteration, but you don't seem to mean that sort of thing.But if iteration isn't permitted — sime
Not sure what kind of evidence you'd consider proof. We have a CTC, which probably involves some huge machine that impossibly makes the right kind of exotic matter needed to hold some sort of pipe open, an effort that must be made at both ends. The empirical appearance of that is something like a white hole, an event horizon out of which stuff comes, but nothing can go in.if iteration isn't permitted then is sending information backwards proof of a loop? — sime
We wanted an example of time travel that didn't directly contradict Einstein's theories. It is a straw at which we can grasp.For if contradictions are ruled out a priori, then what justifies the use of a loop topology?
If it changed history, then it isn't a CTC (a loop). It would be more of a branching interpretation where multiple histories are meaningful. You can't prove that the branching interpretation is time travel either since it is valid to interpret it as sideways travel, not backwards or forwards.E.g suppose that it is possible to send sports results backwards in time. If this action "changed" history,
All actions produce effects. Non-local meaning retro-causal? But you've no evidence of history having been changed unless a history book (the sports score say) comes back, and is demonstrably different that the changed history that subsequently plays out. But in that case, you just assert that what came out of the portal wasn't from the future, but just random wrongness. Sports outcomes very much would be subject to change by a machine predicting its outcome. In the CTC, there is but the one history, consistent with the information from the loop.then many people (including myself) would interpret this as merely referring to the action producing significantly non-local effects in our present, so that we can preserve the meaning of the word "history" as referring to immutability.
The sports game being correctly predicted is pretty good evidence, albeit not proof.On the other hand, if the action cannot "change" history, then what is the proof that anything has actually been sent backwards?
I'm unfamiliar with such games, but the stance seem to be a valid one. I've been known to argue that given a premise of the principle of locality, ontology sort of works like that, but caused by interactions, not actions or knowledge.To return to the presentist reasoning I sketched earlier, It is logically consistent to believe that the past of our world is generated 'on the fly', as in a roguelike video game that generates the content of the game world as an effect of the adventurers present actions. — sime
Not at all unlike Schrodinger's cat. But that's not information being sent backwards. Maybe the magic spell is an exception to that, but I don't know the details. At no point in the past does the thing behind the door get information about the future actions of the adventurer, any more than does the cat.In such worlds it might appear that information is sent backwards. E.g the adventurer is in an unknown dungeon with a closed door. Only after he opens the door does the game decide what lies beyond the door.
That's good because nobody is finding himself suddenly in a prior time.Notably, players don't typically interpret "history change" as time travel
The monsters behind the door don't get re-randomized? Does it place the player in the prior state as well, doors unopened, health reverted, dead friends un-killt? That would arguably be a time travel spell, but unprovable because information (the wiped memory) didn't go back with it.when an adventurer uses a magic spell to re-roll the state of the dungeon around him, but merely as magic affecting the global state of the present. Amusingly, a philosophical dispute once arose between players of the single-player roguelike game Nethack. In that dungeon crawler there exists the "Potion of Amnesia", which if drunk by an adventurer causes the game to delete it's record of the adventurer's knowledge of the game world,whilst leaving the actual game world in tact, meaning that the player must rely on their personal memories when their adventurer navigates and relearns the content of old locations.
It's just leverage of a dualistic mind. The adventurer's 'mind' (wiped) and the player's mind (not wiped).But isn't that cheating? Shouldn't a true potion of amnesia change the world itself? Players are divided.
Sounds like the epiphenomenal time travel first mentioned in the OP. There is zero violation of physics with that one, and is equivalent to stepping out of a cinema to cross the hall and watch a different movie, perhaps the same one, but back at the start of the story.For me, in fiction, there are 3 basic models of time travel:
1. One univerese, you can't change the past, just re-enact it. This is like 12 monkeys. When you go into the past, you can certainly do stuff and feel like you're making choice, BUT those choices are already necessarily part of that past - your actions during your time travels are a necessary part of the past and were already a part of your history, you just didn't know it. — flannel jesus
Yes, the fictions are kind of full of this, but it is empirically a branching interpretation. OK, BTTF has the photo or something that is evidence of it being one universe, but that trick is entirely inconsistent with any valid view.2. One universe, you CAN change the past. This is probably what most people imagine when they talk about time travel. Pretty sure Back to the Future was like this.
That part is empirically consistent with the branching model, not any one-universe model, unless the machine has omnipotent powers to actually recreate the entire universe. This whole bit was discussed (ad nauseam) in the other thread, coming to one conclusion that this sort of time travel (one universe, getting altered) has a very low probability of survival.When you go back to the future, the future you go back to is different from the future you came from, because the past is different now. — flannel jesus
That's the branching interpretation. The parallel universe has no history prior to your appearance, but they don't know that.3. Parallel timelines. When you go back to the past, you're not going into your OWN past, you're jumping into a parallel universe that's the same as your universe, but in the past. — flannel jesus
That statement presumes that universes 'chug along'. I agree that the old world still exists, and perhaps 'you' don't even leave it when you travel to another world. There's two ways it can happen: You vanish from the one world, or you don't, and there is now two of you, one in each world. The latter is far more consistent with MWI and with physics. I've not really yet done a post on this point since nobody has expressed interest in that scenario until now.You can make choices in this universe that are different from the past of your own universe, BUT your own universe is still chugging along into the future without being affected by these changes.
How very elegantly argued. I see you even have gained toady support.You and others have proffered fanciful alternative realities, curly time, elastic time, ragtime, Miller time or whatever, which I admit to not reading with close attention.
Bottom line: No, you can't travel in any of them. — Vera Mont
Agree with all, but it is Newtonian physics, the stuff of 19th century and before. Reliable indeed, since that's what was used to put people on the moon.Well. Cannon ball trajectories (roughly) form a parabola over time. The position (spatial) can be expressed as a function of time. Physics. (High school if memory serves.) Meaningful, reliable. — jorndoe
Solid evidence that you don't even read the posts, and confirmation of my earlier assessment.There are different species of time? — Vera Mont
I am going to disagree, but draw a similar conclusion for different reasons.I think that the concept of non-local causal cooperation that you allude to is interesting and useful, but i think CTCs are empirically inconsistent and theoretically unnecessary. For any proposed loop, if you could experience going around it more than once, then the proposed loop would be falsified (since the second iteration would be distinguishable from the first). But if you cannot experience going around the loop, then how you do know the loop exists to begin with? A theory containing a CTC cannot have empirically observable consequences on pain of contradiction. — sime
No worries, but I'll leave it mostly to you. There's not much traffic that you're interrupting, but you're banging against a wall with your efforts. Opinions held deliberately in ignorance are not usually changed. Evidence of that:Apologies ↪noAxioms, didn't mean to distract the time travel discussion. — jorndoe
There is no body of evidence supporting the picture you just described.Okay. So time is a physical entity, with form, spatial co-ordinates and dimensions, which co-exists with the world in which we experience time only as processes, events and changes. In theory, a person can step from the 3-dimensional world into the stream of time and back again.
The body of evidence for this is found in which scientific discipline? — Vera Mont
That was sort of the main simple example in the SEP article. Fred sneaks into a museum, steals the time machine, goes back a bunch of years, and donates the machine to the museum (explaining what they're doing with one). He doesn't use the machine again, so nobody goes around twice. But the machine violates entropy. It cannot have an odometer or any other evidence of age without invoking the contradiction you point out. So the machine (never created) is self perpetuating, and will do so forever according to its circular worldline.For any proposed loop, if you could experience going around it more than once, then the proposed loop would be falsified (since the second iteration would be distinguishable from the first). — sime
A time curve doesn't require 'the same thing' going around more than once, but if one end is in the light cone of the other, it's technically closed, and thus a loop. It has little to do with 'experience', but one of the presumptions of the definition of 'time travel' is that a person does it, not just his dog or his class ring.But if you cannot experience going around the loop, then how you do know the loop exists to begin with? — sime
I don't think this is true, but the dangers are definitely there. A CTC would be by definition consistent with itself, but that means that any information going back cannot be leveraged for the purpose of preventing the future state of the other end of the thing. So a closed loop can be (must be) contradiction free, but it seems to allow the contradictions, which is unacceptable.A theory containing a CTC cannot have empirically observable consequences on pain of contradiction. — sime
I don't think I in any way presented a sound rebuttal of that conclusion.So a CTC can at most be an uninterpretable expression of mathematical convenience rather than a representation of a physically verifiable entity. — sime
I'm sorry, but the Roman hoard isn't backwards directed. The Romans were first and caused the hoard. The dig did not. Archaeology was my example of forward causation that didn't involve light the whole way, unlike say 'looking at' light from a star 100 million light years away.As for archeology, how do you know that the practice isn't retrocausal? Consider that the effect of digging into the ground can be expected to produce both predictable consequences that we might call "forwards directed" e.g the dig producing a hole next to a mound of earth, as well as unpredictable consequences that we might call "backwards directed", e.g the dig revealing of a Roman hoard of treasure. — sime
Under what view would it not? Idealism, sure, but they don't ever think it exists, only the experience of it. While I don't presume counterfactuals, the hoard doesn't count as one. I'm not considering any epistemological definition of things unless specifically discussing a view where such things are fundamental. And the archaeologist is very much getting credit for the epistemological existence of the hoard.For why should the hoard of treasure be assumed to exist before it was discovered in the hole? — sime
Depends when that assumption of prior existence is being made. The answer is quite different if you've already dug it up.why should the hoard of treasure that was unearthed be assumed to exist prior to the establishment of the archeological evidence that they determined day before? — sime
I'm unclear on how your example illustrated non-locat causal cooperation. Sometimes I'm a bit slow.So in short, i think the concept of non-local causal cooperation (Synchronicity?) is a causally permissible concept that aligns with experience, but I cannot say the same about closed time-loops. — sime
In language, the duration is context dependent. Mathematically, only zero duration avoids contradictions.I do not know with any certainty how long "the present" is. — BC
'The past' can be meaningless since it means 'times prior to the present', which, in the absence of a view that includes a premise of the existence of 'the present', renders the the phrase about as meaningful as 'one KM northward of the teapot that orbits beyond Jupiter'. That phrase simply doesn't define an actual location in space without an additional premise of the existence of the teapot out there. If the premise is made, then the phrase has meaning, even if the location of the teapot is unknown.I do not understand how the past can be meaningless. — BC
You have a past — BC
Your opinions. They're fine, but only opinions, and as stated above, much of the discussion revolves around a different view where there is a there there.That view isn't falsified by assertions and laying and kicking legs in the air.If I went back a year,
— noAxioms
There is no there there. — Vera Mont
Simultaneity seems only meaningful in coordinate time (if there is no teapot time), or teapot time if there is.Isn't it more that events have temporal locations?
Anyway, duration and simultaneity are meaningful enough, and suggest some temporal structure taken together. — jorndoe
In what way is that not forward causality. I mean, I think that sime above attempted to explain something on those lines, but not sure if I got it.What archeologists look at is bits of pottery and and metal and walls that they dig up in old habitation sites. — Vera Mont
I'm not saying it is, but that simply isn't the point of the topic. In a stretch, it could be, especially with exotic matter. Thing is, exotic matter, while mathematically consistent with theory, is not something that can be manufactured or manipulated.I do not believe time travel is possible. — BC
I personally don't put a whole lot of stock into the concept of 'the past', and most (but not all) of my discussion kind of assumes the concept is meaningless.I look at the past as a crystal
OK. And what if God has seen fit to do exactly that, but not write about it? What would that be like? It's a valid point, and one that I neglected to include in my list.God ... has not, according to our founding fictions. seen fit to do over any part of the past.
But you did say:
":SEP envisions time travel ... to a destination time selected"
Yes I did say that. Travel to a time is like travel to a spatial location, and not to a place where 'space' is stored. Time travel is no different in that respect.
— Vera Mont
Pretty much, yea.This means a physical body in a physical container, being transported from a point of departure to a destination, which would have to be an actual place where an actual body can land.
No memory is completely verifiable, so I disagree with this statement. If I went back a year, I could make some (but not all) predictions about things I remember, so that very much does sound like a verifiable memory. I say 'some' because I'm a firm denier of fate, and my presence a year ago would change many things. The BTTF sequel with the sports almanac wouldn't work, but predicting comets and close meteor encounters would.messed-up, unverifiable memories don't count.
It's spacetime terminology from relativity theory. Hard to discuss that if you're unfamiliar.In block terms, time travel is either a discontinuous worldline, or a worldline that isn't everywhere time-like.
— noAxioms
The what now?
Anyone can look at the past, which isn't any sort of retrocausality. I mean, that's exactly what hte archaologists do. It's looking forward or causing some effect backwards that's the trick. Most of the plausible scenarios I have in mind require cooperation at both ends. No travel to a time that isn't expecting you, but rather a portal deliberately held open at both ends to let information or more through. So in that scenario, there's no 'changing' of the earlier time since the travel back to that point was always there. That's the nature of a CTC. SEP had some examples of this, but I find them implausible.The most you can hope for is that someone in the past made a faithful virtual recording of some aspect of their world, and you can access that recording through some device. Like old movies.
Well I didn't say 'travel to where they keep time'.time has no physical locations — Vera Mont
No argument, but also not the point of the topic.I don't think there is any hope for time travel. — jgill
Well clocks measure a kind of time (proper time), so that type is real, at least if you consider the clock to exist outside Human cognition. Coordinate time is another type, and that one is purely an abstraction (or it is under relativity, but not so much if you don't accept its premises).Do we know if time exists outside of human cognition? — Tom Storm
Engineering issues are not a concern to this discussion, only the implications on current philosophies if it could be pulled off.The important question here is cost — BC
It was brought up elsewhere. If you go to watch the T Rexes mate, you either were always there, or you changed something. If a change was made, there's no going back to the world from which you departed. Humanity beyond what you brought with you is gone.the thrill of watching T Rexes mate — BC
This part is specifically absolutist, since the assertion isn't true without a preferred foliation of all spacetime events.The universe is in a state at one moment, then another state in the next. — Philosophim
This implies the classical causality. In a classic sense, this works, but given closed time curves (CTC), there is not an objective ordering of causal events, and CTCs are valid solution in relativity theory. I'm not sure how growing block handles a CTC.The reason why the universe is in one state is because of the forces and matter in the previous state.
'Reshape' is the omnipotent power thing I'm disallowing, so we either utilize one of those closed curves, or we actually 'travel' to 1000 years ago and make some local difference (similar to wave function collapse) that spawns a different causal progression from the mildly altered state (similar to MWI).Meaning that if we could reshape the forces and matter to what it was 1000 years ago, we would be in the state of the universe 1000 years ago. But we can't go back.
That finally seems like a direct assertion of growing block view. You can 'go to' the past since it exists, but you can't go to the nonexistent future. But growing block says the past can't return to the state of 'is happening', so at best your presence there would be epiphenomenal, or again, the creation of a new branch, which is more sideways travel than backwards.There is only now, and what was before.
I don't consider it a 'part', no. I don't see perdurantist language in the field, so I don't use it. A part of a 4D object would be a smaller 4D object. A finite number of parts make up a finite whole. The 3D cross section you describe corresponds to a state of Floyd in presentism. Floyd is in one state at noon, and a different state at 1. None of those states move since each is at but one location ever. But Floyd is still said to move in presentism. Your argument seems to be equivalant to Floyd not moving because none of his states do.You refuse to acknowledge that Floyd at noon is but a 3D part of a 4D object. — Luke
There you go again, putting straw man assumptions in my mouth.The noon-part of Floyd doesn't change its temporal or spatial location, like you assume.
And reiterating discriminatory definitions as well. I showed that definition to be false even in presentism (the shadow), and you didn't counter it, but rather came up with irrelevant comments about its causes.The definition of motion is a change in a 3D object's position over time.
So you've proven what nobody seems to be able to do, which is to falsify eternalism. Kindly detail some empirical falsification test, Love to hear it.I'm only saying there's technically no motion in an eternalist universe. This needn't imply that there's no motion in our universe, only that if there is motion in our universe, then our universe is not (purely) eternalist.
'Floyd at noon' indeed describes a 3D object, yes. Floyd at 1 is a different 3D object, but it is all still Floyd, and the difference in Floyd's location over time is, by definition, motion. It is entirely consitent with B-series language which any eternalist uses without contradiction.You are treating Floyd as a 3D object, not as a 4D object. That is not consistent with eternalism. — Luke
I did misread it, so thanks.Presentism is a theory of existence, whereas endurantism is a theory of persistence.
I think you've misread. I said presentism, not perdurantism. — Luke
But I never disagreed with the 'corrected' statement.Huh? No, it wasn't hard to correct you.
I never said any such thing, in the context of eternalism. The 3D things are (per the perdurantists) separate 'parts' of the 4D thing. It is the 4D thing said to move (change locations over time), not the parts.You are again assuming that Floyd is a 3D object.
I gave an example where this wasn't true, but I know what you mean. To summarize, by definition, no event that is part of Floyd can be at different coordinates in an inertial coordinate system. It's true of a 0d event, even if not necessarily true of 'parts' consisting of 1-3 dimensions. But motion isn't defined as an event having more than one set of coordinates. It is a difference of location at different times, and Floyd meets that definition.No 3D part of Floyd changes its temporal or spatial location
To meet your discriminatory definition maybe. Floyd is home at noon and at grandma's at 1. That is motion by the definition. That's how the language is used by an eternalist. The language is serving its purpose, which is to have meaning, and it does so without needing to change the definition from 'change locations over time'.which is what a 3D part must do in order to meet the definition of motion.
Do you understand a 3D cross section of a 4D object? All the events on the arbitrary slice can be assigned the same time coordinate so long as the slice is space-like. Angle the slice a different way and a different set of events (except those events at the intersection of the different slices) are now assigned the same time coordinate. This is essentially a change of reference frame, coupled with relativity of simultaneity, with which I suspect you are not familiar else you'd not be asking that question. A loaf of bread is often the analogy (slicing a 3D object, with time being the long dimension say) along 2D spatial planes, arbitrarily oriented. A slice through a given event (the center of the loaf say) can be angled in many ways and still include that one event, so all the other events are only part of some slices and not part of the others. That's relativity of simultaneity in bakery terms.Any slicing does this.
— noAxioms
How?
Alice1, at the tracks at t=12:00:30 travels back 30 seconds to being there at exactly noon. So Alice1 is at the tracks at noon. Alice2, at t=12:00:30 also selects that same noon event as her destination, so she clones the Alice1 there and the first-noon version of Alice2 (not at the tracks), to create two new clones Alice4 and Alice3 respectively. Alice 2 and 4 are occupying the same space at the tracks simultaneously, and one doesn't survive that.How does Alice4 (Alice1's clone) come into existence?
Time travel under eternalism is simply any non-timelike worldline, and, if you take the SEP definition, any non-straight worldline. The sort of travel you've been envisioning would be a discontinuous worldline. A continuous but not timelike worldline would have an undefined proper time, meaning it's not clear what the subjective duration of the travel should be, but the external experience of the machine would be much like the description of Putnam in SEP. Funny that his machine sort of has to accelerate to some speed (88 mph just like in BTTF) to make the jump.True, but time travel is also not possible under eternalism since nothing moves in a 4D universe. — Luke
According to the article you linked, both are alternate interpretations of persistence. Despite what various articles might call them, neither is a theory since they both lack any empirical falsification test.Presentism is a theory of existence, whereas endurantism is a theory of persistence.
And I've shown otherwise, so you're simply wrong. The eternalists use all the same language as do the presentists, but formally, only references to the nonexistent extra thing is what makes a statement meaningless. Motion has meaning under eternalism since a statement such as 'Floyd takes an hour to move from A to B' has meaning.there is no motion in an eternalist universe, as I have argued.
That wasn't so hard, was it?Surely you mean that a 3D part of the 4D object has one location at a given time and a different 3D part of the 4D object has another location at a different time.
It produces motion by exactly fitting the (not my) definition: Floyd is at one location at one time, and a different location at another. Floyd moves even if what a perdurantist calls his temporal parts do not.You need to explain how two different 3D parts of a 4D object can produce the change required for your definition of motion, when neither of those 3D parts ever changes its temporal or spatial location in the block universe.
Any slicing does this. The positing of a preferred way is known as 'absolutism'. The first premise of relativity is that there isn't a preferred way, but it's a premise, meaning relativity isn't proof against a theory that doesn't accept that premise. The slice can be odd shaped. It need not be flat, but it does need to be space-like, else you end up with events that occur out of causal order.Okay, but which preferred method of slicing allows for a 3D part of a 4D object to change its temporal or spatial location?
All the Alices are herself, and Alice1 made it across the tracks without crashing. Alice4 dies immediately upon coming into existence, and is the shortest-lived Alice.Alice2 can only clone herself.
Mostly right. You didn't mention the Alice that collides and dies with Alice2 in that description (so 3 Alices coexisting at once, but two of them dead). The time machines were cloned as well, so there were 4 of those, one truncated away, two crashed into each other, and the only one remaining is the one never used.Your scenario, as I now understand it, is that Alice1 time travels backwards and "clones" Alice2, such that Alice1 and (Alice1's younger self) Alice2 now co-exist at the same time. If Alice2 now time travels backwards, then she will clone Alice3 (Alice2's younger self) and Alice2 and Alice3 will co-exist at the same time. Alice1 will no longer exist, just as all the people on the timeline when old Bob departs and time travels backwards no longer exist. That's what it means to overwrite the timeline; the timeline reverts back to its earlier state at the traveller's arrival time, except that that time now also includes the time traveller and their time machine.
"To take place, occur" is what I get from a google query. That works fine, since the definition isn't specifically crafted to exclude the undesirables. To exist means 'to have being', to be real. I can be an eternalist (or presentist for that matter) without being a realist, so an event need not exist in order to happen.I didn't realise there were two different definitions of 'happens'. — Luke
I could probably craft one that excludes the undesirable presentist view, but doing so wouldn't in any way constitute evidence that a view excluded is wrong.What is the eternalist definition of 'happens'?
Then time travel isn't possible under that definition of presentism since it would constitute travel to some destination that doesn't exist.presentism holds that only present objects exist.
I do, because all of the alternate versions still posit a preferred moment in time, which is the fundamental different between any of them and eternalism.I don't use the term "presentism" to refer to any "4D versions of it".
Presentism doesn't face this problem, because only at most one of those frames can be correct, and probably neither are.Objects lack temporal extension under both presentism and endurantism. Both theories face the same problem if there are two or more frames of reference (or "present moments") involved.
I try not to hold hard beliefs. I know both, and can discuss either. The purdurantist wording seems silly to me. I've never seen its terminology used in any practical discussion, such as in the science community. And science definitely uses both eternalism (especially in a discussion of cosmology, relativity, physics, chemistry), and presentism (astronomy, climate science, biology, anthropology). I never hear anybody use 'temporal parts' or 'wholly present'. One context uses B-series terminology, and other contexts use A-series.The question was basically asking if you are a presentist (endurantist) or an eternalist (perdurantist).
No, your definition is thus confined, worded specifically to exclude a view you find undesirable. 'The definition' : 'to change position' isn't so confined.The definition of motion is confined to a presentist view, I agree
No, a purdurantist universe contains this. Don't confuse the two.An eternalist universe contains 4D objects
It does not follow that the lack of motion of a 3D 'part' implies the 4D object does not meaningfully exhibit motion.. At no point in any of that do you mention that the 4D object has one location at a given time, and a different location at a different time (which is how an eternalist would word it), which is, by definition (not by your definition), motion. The 3D references are perdurantist phrasing, and the argument above is still doesn't demonstrate that the object doesn't move, only that a specific temporal part doesn't, which of course it cannot since it would need time to do the moving.4D objects are divisible into different/discrete 3D parts
Each 3D part of a 4D object exists at a different time
No 3D part of a 4D object exists at more than one time
A 3D part must exist at more than one time in order to be able to change over time
No 3D part of a 4D object can change over time
No 3D part of a 4D object can change its location over time
Therefore, no 3D part of a 4D object can move, according to the given definition of motion
Nonsense. That's what a frame change is, slicing through the same point (a given event, which has a specific time) at a different angle, which makes for two very different temporal slices. I take it by this that you're entirely unfamiliar with Minkowskian geometry.You cannot have two temporal slices at the same time.
If I slice a 4D object across a spatial axis instead of across the time axis, I end up with a 3D object that has one temporal dimension and two spatial dimensions. The location in 2D space changes over time.It is analogous because no 3D part of a 4D object can change its location over time
— Luke
Not true actually. You just need to slice it the right way.
— noAxioms
Could you explain further?
How it handles collision is critical to identifying the implications. If I don't know how the machine handles targetting an event where there's already something else, then we cannot explore the implications of a trivial situation where that necessarily occurs.I'm interested in the philosophy of time, and the implications on the different theories of time.
You change the story several times, so I wasn't sure which you had settled on. OK, so they both die, Alice3 comes upon the death scene and perhaps doesn't decide to add herself to the wreckage, and chooses to miss her important appointment instead. The universe doesn't end (this time).I've said several times that they both die. Why won't you accept it?
There's four Alices,. Sounds like cloning to me.That's one way of looking at it, I guess. But it also overwrites the timeline and deletes the timeline that the traveller departs from. I wouldn't call that cloning.
That was the convention I had initially chosen. We switched to yours. My convention had only three Alices (not four), and everybody else (Alice or otherwise) was an original. In a way your convention is better, because each person (traveler or not) has a unique history. My convention has a given person (the guy mowing his lawn nearby say) multiple histories that play out in different ways, which violates identity rules.The only one being "cloned", or the only one who has two versions of themself in existence at the same time, is the time traveller.
Clone of Alice1, made by the travel of Alice2. Alice4 lives but a moment and is gone in the collision with Alice2. Alice2 lives 30 seconds, and dies in collision with Alice4. I did say that Alice1 is the only happy Alice. It sucks to be any of the others.Where did Alice4 come from?
Right. Her travel creates Alice2. Alice1 never time travels again. She lives but 30 more seconds and is truncated into oblivion.Alice1 is still Alice1 after she time travels. She is the original.
No, Alice2 lands on Alice4. Alice1 doesn't land on anybody, which contributes heavily to her being the happy one.So it is Alice1 who lands on Alice2 and they die as a result
Well, 1 is gone, 2 and 4 die in a crash, so only Alice3 survives (if she chooses to lay off the button). If she still hits the button (but in a different place than where the wreck is, and for maybe a different jump than 30 seconds, then she can make a whole bunch more dead Alices, herself included, since no actual traveler survives the experience.and then the timeline continues without any Alices
Totally agree. My usages of 'happens' for instance, in eternalist context, are logically consistent, and many of yours are not. Perhaps you are trying to use the presentist definition of the word in a non-presentist context.The observation that "those words can be applied to a block view" doesn't make it logically consistent (with eternalism) to do so. — Luke
Two of the three imply motion. Motion is not the fundamental difference since both have it. I've said repeatedly: the fundamental different is that presentism posits a preferred moment in time, and eternalism doesn't. That, and only that, is the fundamental difference. All the rest just follows.They all imply motion which, I believe, is the more fundamental difference between the two views.
The perdurantist position seems to very much be about parts, yes. That's for the perdurantists to defend. I've posted some inconsistencies I've found with that.it’s all a matter of parts.
OK, I think I did misread that. The question comes down to then: Is there a difference between somebody claiming to be endurantist and claiming to be presentist? There are several forms of presentism, so perhaps endurantism is but one of them, perhaps 3D presentism, as opposed to growing block, spotlight, and other 4D versions of it.This is the endurantist view. It is consistent with presentism due to the lack of temporal extension of its objects which are, therefore, not divisible into temporal parts.
Yes, I withdraw that. The concept of a worldline implies 4D spacetime, and 3D presentism does not have meaningful worldlines, but 4D versions of it do still have worldlines.Therefore, the phrase "wholly present" is not, as you say, "a reference to all events in the object's worldline".
Actually, there is no Andromeda paradox under presentism, in any of its forms. Presentism denies both premises of special relativity: 1) Physics is the same in any frame. Well, it isn't. The whole point of presentism is a preferred frame, and all the others are wrong. 2) Speed of light is the same in any frame. Under presentism, that's false. The speed varies depending on which direction it is going, relative to any frame which is one of the 'wrong' ones.I agree that the answer depends on which reference frame is present and so may be considered as ambiguous.
However, why do you say that presentists don't have this problem?
You seem to be mixing views in that query, rendering the question meaningless. If you're asking about eternalism, then keep it to those terms. I've never heard an eternalist talk about something being 'wholly present at some time', which seems not even wrong.Are "you" a 3D object that is wholly present at each time or are "you" a 4D object temporally extended over time?
That is a decent description of movement in perdurantist terms, which I find needlessly complicated. The science community never uses such cumbersome terminology to say something so simple, which is why the 'temporal parts' page was largely educational for me.If you're a 4D object then a temporal part of you is home at noon and a different temporal part of you is at grandma's house at 1.
OK, then your definition is confined to a presentist view. That doesn't mean that a non-presentist must use that definition. The definition I gave works for both, and I've never seen a dictionary restrict the definition to 3D things. In short, my google query says 'move' means to change position. The shadow of a pole moves, and it isn't a 3D thing.My argument is that the definition of motion as 'a difference of location over time' applies only to 3D objects.
So per the perdurantists that use that sort of language, 'you' change position over time, but the parts don't. It's still you doing the moving. You're just trying to leverage your private definition onto a view that defines the word differently, which of course makes it contradictory. But that's a straw man fallacy.The 4D object is all "you", but it's not the same temporal part (3D part/object) of you at one time as it is at another time.
Yes, but one slice can be at gradmas house and another (at the same time) is not, so I find it to be a problem. The 3D things posited to 'exist at a time' are ambiguous without also positing a preferred frame.You still end up with different temporal parts no matter how you slice it
Not true actually. You just need to slice it the right way.It is analogous because no 3D part of a 4D object can change its location over time
This implies that all the points of a steel bar are at the same location at a given time. The bar changes its location over length instead of a change in location over time. This fits the definition of change, if not motion. Other examples of change not over time: The air pressure changes with altitude.just as no part of a rigid steel bar can change its location along its own length
No, but I do if I'm suddenly in the same place as air that wasn't there just before. If the machine is nothing but an air-filled balloon, then suddenly twice the air would be in there, and it might very well explode from the extra pressure.Does air die/explode?
No, that is coming from one side, pushing aside what was there. OK, so maybe it pushes stuff aside. In what direction? Does it do it instantly? That would be a nuke explosion. So it takes time, perhaps expanding outward from a point, which will certainly destroy a Delorean inside of which this growing object suddenly appears. But in such a case, the new machine is alive, and any object already there is shoved aside, possibly crushing or exploding it. The tree would not take it well, and the remainder would probably fall and crush the machine that just teleported under it.It would be no different to moving the time machine to a particular location in normal time.
Doesn't work since the form physics is normal motion, say from one side. Where does that start? From how far away does it effectively come? If it comes from a side, then somewhere it has to initiially appear, and not come from even further to the side. So far, the answer is that it teleports in somewhat off-center of target (destroying whatever is there), and then forcibly moving over to the actual target spatial location, possibly pushing/crushing the additional objects that are there, and of course crashing your own machine, since a vehicle collision is what happens when two things move into the same location in normal motion.Let's say that whatever happens to the material already present at the target destination if we moved the time machine there in normal time is the same/similar to what would happen if we moved the time machine there via time travel.
The Alice story cannot proceed without knowing this. Also the extreme example of setting your machine to go back half a second.I don't see understand why you are pressing this point. What difference does it make?
No we can't. My examples are specifically designed to reduce the odds of safety to zero. I'm finding flaws in the view envisioned, which I thought was the purpose of all these posts. The half-second just is obviously going to lang on the machine that is there. Destroying it isn't such a bad thing in that case, but I need to know if that's what happens. If the jump finds somewhere more (but not completely) 'empty' nearby, would it teleport there instead? That's a different solution than the bang-and-push thing you described before. It results in different problems.Surely we can imagine that the time machine can arrive safely
What does it do to avoid it? Go to the moon instead? NASA would love it if your machine did exactly that. So much effort saved. Who cares that it's a time machine. It's also a space teleporter.but let's assume it has the technology to avoid it.
But the possibility of time travel, as you describe it, has exactly those ramifications. If you don't want that, then a different model should be assumed.You seem more concerned about the ramifications of time travel - the end of humanity or the destruction caused by the time machine - than you are with the possibility of time travel.
Alice 1 has already traveled and will not do so again. Alice2 will travel back when she gets to the track, cloning everybody on that timeline, so I guess Alice1 vanishes as does everybody not in a machine that goes back in time.According to my convention, Alice1 is the original; the time traveller. Alice2 is the 30-seconds younger version of Alice1 who exists in the past (just as young Bob exists in the past of time traveller old Bob). I cannot see how both:
(i) Alice1 will time travel back 30 seconds after crossing the tracks; and
(ii) Alice2 will time travel back 30 seconds, 5 seconds before crossing the tracks.
Everybody time travels at noon+30 seconds, back to exactly noon. At noon+25 seconds each virgin Alice gets to the tracks and has 5 seconds to assess the situation and decide to go back 30 seconds or not.and if Alice2 time travels 5 seconds before crossing the tracks
Maybe. She makes it to the crossing too late, hits the button, goes back 30 seconds, and if her collision with Alice4 isn't noticed, she probably considers it mission accomplished and proceeds to cross the tracks just before the gates start coming down. But I don't think the collision will go unnoticed, which likely will effect whether she proceeds across the tracks or not.then Alice2 will not proceeed to cross the tracks
Alice1 is the first to jump, and lands on nobody. She proceeds across and is truncated out of existence when Alice2 pushes her button. Alice1 is the only happy Alice, so it's a shame her life ends so abruptly.If Alice1 lands on and kills Alice2
It is not an assumption, but rather an observation that those words can be applied to a block view, and that they don't mean that it is an assumption that time itself is what flows or moves.It is your assumption that events happen (which you differentiate from mere existence) in an eternalist universe which suggests some sort of flow or motion in an eternalist universe. — Luke
I didn't read it that way. The endurantists statements you make seem to consider objects to have temporal extension (since a reference to 'wholly present is a reference to all events in the object's worldline, and that is, in the absence of a preferred moment presumption, an eternalist stance.Perdurantism has temporal extension; endurantism does not.
Perdurantists believe that ordinary things like animals, boats and planets have temporal parts (things persist by ‘perduring’). Endurantists believe that ordinary things do not have temporal parts; instead, things are wholly present whenever they exist (things persist by ‘enduring’).
Objects of course. I'm at home at noon, and at grandma's house at 1, a different location (relative to the frame of the surface of Earth) over an hour's time.Motion in a block universe is a difference of location over time, just as it is in presentism.
— noAxioms
Motion and/or location of what, though?
Well I just applied that definition to a 4D object just above.My argument is that the definition of motion as 'a difference of location over time' applies only to 3D objects.
OK, this is just a refusal to use the typical identity convention, that me at one moment is not the same me a second later, but rather two separate entities. Regardless of a presentist or eternalist stance, if that identity convention is used, then indeed, nothing can move, by definition. There are valid attacks on the usual identity convention, so this can be a reasonable alternate convention. I think I can disassemble any identify convention by choosing the right example, so I don't suggest any one convention is necessarily correct.Since each 3D part (of the 4D object) exists at a different time, then no 3D part moves or changes its location over time.
That usage of 'move' does not conform to the definition given, so no, it isn't analogous.It would be analogous to part of a steel bar "moving" along its own length; it doesn't happen.
My bad. Some of the notifications are not coming through. Will try to reply to parts not covered since.I have no idea why you think I never replied to your post from a week ago.
I asked for how you envision interaction with material already present at the target destination. Your answer was simply 'die/explode'. So perhaps the answer needs to be changed. Maybe it handles air better, by what, pushing it aside first? Absorbing it (which probably covers 'die' pretty well)? The answer you gave does not imply that it simply replaces what was there with a new state (terminator style, except with electrical effects preceding).How would air, dust or bugs at the destination prevent time travel?
That's a different answer. So it assesses the target, and selects somewhere close? Does it have a limit as to how far (both spatially and temporally) it is willing to look for a satisfactory point in which to insert itself? What does it do with the stuff that is already at the selected point?If the machine can time travel, then it can probably find a safe place to arrive.
Two travel events (both by younger Alice, traveling for the first time ever), each one making a clone, so yes, three of them. Did you forget the machine makes clones?You've lost me here. There are three Alices?
Depends on your identity convention. Which do you consider to be the original in the just-truncated history, the one that traveled, or the younger one that has not, but is about to? When she does, at noon there are two or three Alices, depending on the microsecond timing. If the 2nd destination event happens ever so slightly sooner than noon, it erases the noon event of the appearance of the Alice that makes it across the tracks, and there still remain two Alices, the one that just appears, and the one 30 seconds back that is approaching the crossing and is going to hit the button in 30 seconds.Alice goes back 30 seconds. Okay. Then there is also an "Alice behind". Is she the same Alice as the one who just went back 30 seconds?
She is always there. Nobody traveled back far enough to erase her from history. She's the one that has never traveled before, and is late for her appointment.Apparently not, since those two Alices die after one lands on the other. So, where did "Alice behind" come from?
It seems you convention is to consider the traveler to the original, and the other in the timeline to be the clones.However, now a third Alice approaches the tracks to find the wreck of the collision that killed the other two Alices.
Using your convention, the original goes back (Alice1), who crosses the tracks,. Alice2 is 30 a clone, 30 seconds younger, and will get to the track in 25 seconds and will decide to go back 30 seconds to make it across. Alice2 goes back to noon, explodes and dies in a collision with identically aged Alice1 who also appears just there, and Alice3 (30 seconds younger than 1 and 2) will get there in 25 seconds.Where did third Alice come from? Was it only the first Alice who time travelled?
They are all Alice, but I put numbers on them to keep track of the clones. I used your convention.If these are different people then why did you call them all Alice? This is very confusing.
If it doesn't wait for the destination to be written, then yes, it is blank. If it just makes up a state to write into that blank space, then fine, it puts something there, all very BTTF. Nobody can tell anything is weird except those who witness (or better, catch on video) the appearance of the time machine out of nowhere.Your argument is supposedly that my presentist model entails a blank future universe.
Your model had truncation. This statement seems in contradiction with that term, which sort of implies that when the present is moved back to 1990, the written state of things between 1990 and 2024 is reverted back to a blank state. Now you suggest otherwise. All very self contradictory. Perhaps more clarification is needed as to what exactly happens to the 34 years between when the present is moved back to 1990.I could say that the future has a definite physical existence prior to the time travel
And encounters a slow version of the grandfather paradox where he is threatened with nonexistence by changing the circumstances leading to his birth, a different story than the one you tell. Anyway, that story is full of contradictions, and it doesn't explicitly call out the interpretation of time it is using. The movie probably contradicts any valid interpretation of time.I think many works of fiction depict time travel as I depict it in my model, where the time traveller travels to, and inserts themselves into, a time they have never visited before (as a time traveller). For example, Marty McFly was never in 1955 prior to his first time travel event, and his time travel results in changes to the 1985 he departed (i.e. he overwrites the timeline).
In a growing block model, the past exists but the future does not, but will eventually. Hence the wait. In a moving spotlight model, both exist, and it is merely a matter of 1, moving the spotlight, and 2, creating a destination state that is compatible with the identity convention of choice. In raw presentism, backwards time travel is impossible because the destination doesn't exist, and never will again. Under eternalism, a branching model in Hilbert space is probably the best, but world creation is not really time travel without a simultaneity convention between separate worlds.Presumably backwards time travel works differently. Why should the machine have to wait in forwards time travel if it is not required to wait in backwards time travel?
Putting them in a sequence is a choice, a natural choice, as I've illustrated. I can create a series of pictures that a child can order in apparent causal order, not necessarily in the order in which the pictures were drawn.Why do the events happen in a sequence when they don't exist in a sequence? That is, events do not flow into and out of existence sequentially in an eternalist universe, like they do in a presentist universe. So, why do they happen sequentially in an eternalist universe?
I don't argue for meaningful time 'before the big bang', given a realist definition of the universe as 'all there is', there would probably be more than what is accounted for by just the spacetime that we know. The ability to temporally order the other parts is likely meaningless, so different language is needed to discuss such things.You seemed to be arguing that there are no events before the big bang even though there are times before the big bang,
It's just that every attempt at describing things in eternalist terms still adds references to flow or other implications of a special moment in time.What makes you think I'm ignorant of the theory of eternalism? — Luke
It seems I am.For someone who regularly accuses me of ignorance of concepts in the philosophy of time, I find it amusing that you are obviously unfamiliar with the concept of temporal parts.
This is also mostly a choice of how to use the language, but the tense 'can be happening' in the absence of an explicit time, constitutes an implicit reference to the present, and such references should be avoided. I've said this repeatedly.Before your break, we were discussing whether events can happen (or be happening) in eternalism, so I don't consider a further discussion of the implications of eternalism to be a side topic.
Not at all, but it treats it differently. Different interpretations work in one interpretation or the other, but most not in both.You appeared to be arguing that eternalism is the only theory that can make sense of time travel.
Motion in a block universe is a difference of location over time, just as it is in presentism. What was you argument against that again? Do you deny this definition, or deny that it applies to either view?Besides, you completely ignored my argument against motion in an eternalist universe, just as prior to your break, you never replied to my argument that Alice0 cannot be the original Alice.
Then time travel is mostly impossible the way you envision it since there is always something (air, dust, bugs, trees, whatever) at the destination, unless one chooses to materialize in deep space, and none of your scenarios do that. But here you suddenly suggest that materialization at a location that already has something results in the destruction of the machine and whatever was there before.Yes, if the car/person jumps to the same location as another car/person then they would all die/explode/cause a black hole/etc.
Alright, but when in a discussion where the implications of a specific theory (or its alternatives) are very relevant, coming into the discussion in ignorance of that theory doesn't put you in a position where your view can be coherently argued.Yes, because most people are not physicists that understand relativity theory. Hence, "commonly held". — Luke
I see what you're saying. It's a funny way of putting it, but I suppose so. I would have called them cross sections instead of 'parts'.3D parts of the 4D object.