Yeah, you can have that argument to yourself.

actually that is the argument of most naturalists and a majority of presentists - a pretty large group of scientists / philosophers

you still exist/existed/will exist on the points of that worldline

That is exactly right. The issue is what does "existed" and "will exist" mean - are they historical facts available to those who are conscious or are they facts that instantiate a past belonging to the person who does not exist - a past that is their past. The question about the metaphysical implications of tensed language is tied to the answer to our scientific question of whether the universe exhibits fundamental or emergent temporality - are past and future part of physical reality or not. For the spooky action at a distance of Quantum entanglement to work it appears that something like causal set theory, where there are sequential events but no fundental temporality, absolutely must be added to or discovered to be the correct interpretation of GR / QM. This has profound implications for the ontology of human physical existence.

That is exactly right. — CommonSense

You have a tendency of taking words out of context and using them inappropriately. Stop that. Your comment, while expressing an agreement, has nothing to do with what I actually wrote.

But once you build or find your time machine/closed time-like curve, all you need and can do in order to complete your journey through time is what all of us do all of the time: wait, let the time pass. — SophistiCat

This argument makes no more sense to me than saying that traveling to San Francisco is just waiting. I get on a plane headed towards San Francisco and then I just wait.

And if the spacetime topology happens to have a certain exotic configuration, then your waiting may take you to places unexpected. — SophistiCat

It doesn't have to take me to some place unexpected. If I know enough about the closed timelike curve, I can use it to go to precisely the time I'd like to go to. Given that the time I want to go to is contained within the curve, and the CTC is of a sort that lets me do that. And where I want to go to is consistent with the past. I.e., I actually showed up in the past there in the past, etc., etc. But this is a thought experiment, and nothing I'm postulating in it is inconsistent with GR as we understand it, even if it only occurs in a relatively unlikely possible world.

But arguing about such things is a pointless detour wrt whether GR entails eternalism. I've presented a thought experiment where a million people use a closed timelike curve to all travel to different times. As far as I understand things, these types of thought experiments are generally taken by physicists to entail eternalism, assuming GR is true enough that closed timelike curves are actually possible.

Though even Special Relativity makes presentism difficult to defend. See the Stanford Encyclopedia of Philosophy for more details.

I went to a Philosophy conference at MIT filled to the brim with professional philosophers. In one of the talks, the moving spotlight theory was given a quick refutation as part of the argument. Here's a longer discussion. Though this author actually defends the moving spotlight theory as not being incompatible with Special Relativity:

https://web.mit.edu/bskow/www/research/timeinrelativity.pdf

There was Q&A after the talk. Not a single philosopher spoke up to question the implicit eternalism that was presented, nor to support the moving spotlight theory. My natural conclusion is that eternalism is not hugely controversial. Or at least not amongst the philosophers who might come to MIT for a conference.

In any case, eternalism is a simple and natural explanation for what happens in the thought experiment. It is also in my experience how virtually all scientists who talk about GR, talk about GR.

I consider eternalism prima facie true, assuming the thought experiment is actually possible.

I think that anyone who wants to reject eternalism without rejecting the possibility of this thought experiment has a lot of work to do! And I find it highly improbable that whatever theory is presented as an alternative would be widely accepted as more likely.

As for who is better equipped to address such questions, I don't consider philosophers better equipped than scientists. Particle physicists used to consider virtual particles just a mathematical convenience, rather than virtual particles being real. Now virtual particles are universally accepted as real. I don't consider philosophers to be better equipped than particle physicists to determine the metaphysical status of virtual particles wrt existence, and in the unlikely case that philosophers come to a different conclusion than physicists on this issue, I would most likely side with the physicists.

|>ouglas

If experiments can prove B theory, then physics IS philosophy

For the spooky action at a distance of Quantum entanglement to work it appears that something like causal set theory — CommonSense

In MWI, there is no spooky action at a distance. It is a completely local and deterministic interpretation of QM.

|>ouglas

MWI, there is no spooky action at a distance. It is a completely local and deterministic interpretation of QM.

True - however every time something actualizes it creates a new universe so that there are an exponentially number of "me's" approaching infinite, no one of which is a singular me For which it can be said he or she had a meaningful life..

mmmm. It just isn’t.

You're looking for meaning in all the wrong places. There is no meaning to life. Live with it.

If there's any meaning to life, it's the meaning that you yourself decide to assign to it.

|>ouglas

There is no meaning to life. Live with it.

From a purely objective standpoint that is a conclusion that may or may not be true. It is irrational to accept as factually true that there is no meaning to life as long as there is a possibility, no matter how small, that there is a non-physical existence. The idea that one creates meaning by declaring that human beings can assign meaning is the fallacy of Ubermensch.

The problem is that we cannot objectively say that it is irrational to accept the possibility of non-physical existence if we cannot make observations to test our assertions. There may be non-physical existence, or there may be no non-physical existence, after physical death, we cannot say it is likely that there is or is not. We cannot say anything objective about that which may exist beyond human observation - that is common sense.

In the tapestry of time and space, Bill lives forever. His existence cannot be wiped off. The universe would be different without the causal effects of his having existed.

If Bill wants to exist again he probably will.

Whereof one cannot speak...


And yet you try.

1) There may or may not be a non-physical existence beyond human ability to observe. 2a) I cannot offer proof that there is or that there is not, 2 b) in fact I cannot say anything at all about the reality of an after-life. 3) But I can say that there is a possibility, or at least that there may be a possibility, that anything (or nothing) exists beyond our physical universe. 4) It is simply impossible to prove that which is beyond human ability to observe. 5) Yet that does not mean that there is no non-physical existence and after physical death, nor does it mean that there is. 6) It simply means that we cannot say anything objective about the possibility. If there is an after-life then the possibility was real, if there is no after-life then the possibility was an illusion and not a possibility at all. — CommonSense

I call this sophistical - and vicious - nonsense, the propagator of it either himself a victim, or someone who deals in it directly. I invite any educated and thoughtful person to read it closely and critically. This pile of manure sits and oscillates on #6: we can't say anything objective - about a possibility. A variety of this argument is called "God in the gaps." Well, yeah, we can. And do. I numbered the sentences to take them apart and reveal their flaws, a mini-Herculean task for a mini-Augean stable.

We'll do #1 briefly: If reader entertains "may or may not be" arguments as establishment clauses, then I invite him to consider that he, himself, may, or may not be, a hippopotamus, more likely a jack-ass, or for that matter anything else whatsoever, including nothing whatsoever. For the rest, observe the slippery language, undefined terms, fallacious argument, unwarranted conclusions. If you're a buyer, then you'd better get yourself a bag of oats!

The emotional appeal of Life after death seemed to derail your rationality. What is wrong with Tim's healthy scepticism about your belief?

What is wrong with Tim's healthy skepticism about your belief? — Jacob-B

Do you mean my suspension of disbelief? I call myself an ethical Christian (please don't ask...),
meaning my beliefs, as much as I can, are cleaned of any supernaturalism. I invite you to consider what that leaves.

In the tapestry of time and space, Bill lives forever.

Indeed every event has a effect on the next sequential event, weaving a causal tapestry. However, in a purely physical world after his physical death Bill does not continue exist as a being who is conscious of the tapestry. The block universe interpretation of GR does not give us an individual who exists after physical death, rather it provides a worldline with an infinite number of "me's" no single one of which is a unique Bill who can be said to be the Bill who existed before physical death and contributed to the tapestry. There is no mechanism to explain being and becoming, you simply have an infinite number of approximate isomorphs of Bill strung out along his worldline.

If reader entertains "may or may not be" arguments as establishment clauses, then I invite him to consider that he, himself, may, or may not be, a hippopotamus, more likely a jack-ass, or for that matter anything else whatsoever, including nothing whatsoever.

Beyond the possibility that we live in a simulation. which I do not believe, the reason that it is very highly unlikely that I am a hippo is because I am an observable in the scientific sense. A scientist can posit that I exist as a biologic entity and can test their theory by experimentation - do I statistically meet all the criteria of classification as a homo-sapien? That which is not observable because it is outside the range of human ability to perceive, with even the best instruments used to enhance the senses, objectively may or may not exist. I cannot say it is likely that anything exists beyond the observable nor can I say it is likely that nothing exists beyond the observable, I cannot say anything at all about the reality of that which is not observable. Is there anything beyond the physical, I have no way of concluding that there is or there is not, therefore I may simply decide to reject the non-physical (what you call supernatural) but I cannot offer proof I am right.