The first proof begins by analyzing the idea of an infinite succession of years (or days, or any other equal and finite time intervals). This infinite succession of years must be such that it continues forever, and never comes to an end. It can never be completed: an infinity of years elapsed is a contradiction in terms. Now, in his first proof, Kant simply argues that the world must have a beginning in time, since otherwise an infinite number of years would have elapsed at the present moment, which is impossible. This concludes the first proof. — Karl Popper
How do you imagine negative time for yourself? Kant spoke of time, which clearly has a beginning and is always positive. And the past for us is also a positive time. Relative to zeroMaybe I don't quite understand Kant's argument as Popper presents it, but: isn't that as fallacious as arguing that the series of negative integers cannot be infinite because otherwise it could never reach -3? — Amalac
How do you imagine negative time for yourself? — SimpleUser
Kant spoke of time, which clearly has a beginning and is always positive. — SimpleUser
The idea of an actually infinite past in the extensional sense of actual infinity is incompatible with the beloved premise of asymmetric causality running from past to future. — sime
In order to accept the premise of an actually infinite past, one must both theoretically reverse the direction of causality and somehow square that against physics and intuition — sime
and in addition posit a finite future - a situation that is at least as problematic as the original picture. — sime
In physics , the notion of actual temporal infinity is metaphysical in the literal sense of meta-physics, i.e it is a proposition that cannot be falsified, verified or even weakly evaluated through experiments. — sime
However, there cannot be any empirical evidence on the basis of the observable universe to posit a past of any particular length. Therefore, the idea of a potentially infinite past is both perfectly consistent and the least assuming position to adopt. — sime
isn't that as fallacious as arguing that the series of negative integers cannot be infinite because otherwise it could never reach -3? — Amalac
my point is that the argument he used to prove that the universe cannot be infinite to the past doesn't appear valid. — Amalac
mean, the past is either finite or it's infinite, right? What is meant by “potentially infinite” then? — Amalac
With respect to Kant reflected in Popper, the world exists, which makes explicit a necessary origin in time — Mww
Where do he prove that, exactly? — Mww
By asymmetric causality, I am referring to either the belief or definition of causality such that causes come before their effects. This is a physically problematic assumption due to the fact that the microphysical laws are temporally symmetric. — sime
The realist interpretation of potential infinity is that it is epistemic ignorance of the value of a bounded variable. For the realist an unobserved variable has a definite value irrespective of it's measurement or observation . Hence for the realist, the value of a variable is either actually infinite or it is finite, with no third alternative. — sime
The logic of a potentially infinite past in this constructive sense is superficially demonstrated in the video games genre known as "roguelikes", where a player assumes the role of an adventurer who explores a randomly generated dungeon that is generated on the fly in response to the player's actions. — sime
By asymmetric causality, I am referring to either the belief or definition of causality such that causes come before their effects. This is a physically problematic assumption due to the fact that the microphysical laws are temporally symmetric. — sime
With respect to Kant reflected in Popper, the world exists, which makes explicit a necessary origin in time
— Mww
Doesn't seem that explicit to me, how does that follow? (1. The world exists, 2.???, 3. Therefore, the world has an origin in time) — Amalac
That the world exists and therefore has a necessary origin in time, is an analytic...tautological....truth of logic, insofar as its negation is impossible. — Mww
That the world exists and therefore has a necessary origin in time, is an analytic...tautological....truth of logic, insofar as its negation is impossible.
— Mww
Seems to me like that would only be true if the universe were finite towards the past, which doesn’t seem tautologically true — Amalac
I'll plead ignorance about this point, I don't know enough physics to comment on that.
But I guess my point is that the notion of “cause” may not be applicable to the total, as Russell pointed out in his famous debate with Copleston.
If we see the universe as a “set” or “collection/bundle of events”, then there may be no sense in asking what its cause is, just as there is no sense in asking what the cause of “the set of all ideas” is, in the same sense as we would ask what the cause of a rock, or of lightning, is.
But then again, Russell did also say that matter could also be seen as a way of grouping events into bundles, so maybe there is a sense in asking for the cause of sets after all. — Amalac
Evidence that the universe is finitely existent in the past is provided by the mathematically logical necessity of singularities. — Mww
Thing is, experience informs us of the phenomenal reality of the world, but cannot inform us of the phenomenal reality of the universe or of singularities. Can’t use the criteria for what it is possible to know, in determinations for what is not. — Mww
For what it's worth, to think there's a problem with an infinite past in the sense such can't be for the simple reason that infinite anything can't be completed is to assume Aristotle's position that there are only potential infinities and no actual infinities.
It's quite clear why Aristotle thought that way; after all, the definition of infinity is such that the very notion of completion/an end is incompatible with it.
The only supposedly actual infinity I'm aware of is the set of natural numbers {1, 2, 3,...} but then it's an axiom [something arbitrarily assumed as true]. — TheMadFool
What about the series of negative integers? It has no first term of course, but it ends in -1, so that it is “completed” in that sense. Why can't the timeline of the universe be like that (with -1 being the present, so to speak)?
If being “completed” means that one must be able to write down all of the elements of the series, then why should we accept that criterion as the one which determines whether a series of elements can “exist” or not? — Amalac
Evidence that the universe is finitely existent in the past is provided by the mathematically logical necessity of singularities.
— Mww
If you have to look for evidence in support of that proposition, then it's no longer a tautology. — Amalac
It (mathematically logical necessity) may be logically necessary given the laws of physics that govern the actual universe, — Amalac
I thought you were using the words “world” and “universe” as synonyms. — Amalac
I don't know how we could know if time exists outside of our minds or not. — Amalac
The past is infinite and an actual infinity at that; after all, we're at some point in time (this now) that can be only if infinite time did pass [another way of saying completed/actual infinity]. — TheMadFool
The statement that the universe cannot be infinite towards the past because that would imply going through or traversing an infinite number of events to get to the present seems false to me, since it seems to assume that in traveling such a series of events one goes through or traverses from an initial moment to the present, while this infinite universe towards the past by definition has no initial moment.
If, on the contrary, the journey begins at some point in the past which is not an initial moment, it does not matter how much one goes back in the timeline, the events and time from that moment to the present will always be finite, and there is therefore no impossibility in a universe whose time is infinite to the past.
And it makes no sense to say "but the journey begins before the temporal events begin", because there is no point in time in which they begin according to this model (again, by definition). — Amalac
I like what you said :point: "...if being "completed" means that one must be able to write down all the elements of the series..." I think you're on the right track. — TheMadFool
If being “completed” means that one must be able to write down all of the elements of the series, then why should we accept that criterion as the one which determines whether a series of elements can “exist” or not? — Amalac
The solutions to the field equations support it, which are not subject/copula/predicate propositions, but mathematical formulations, and while not analytical, are nonetheless true. If otherwise, the entire human system for knowledge certainty is in serious jeopardy, regardless of its adaptability to changes in observational data. — Mww
But when someone says an infinite amount of time “passes”, if they don't mean that it passes from some moment in time to some other moment in time (which clearly cannot be the case), then I do not understand what is meant by “passing”. In the case of a universe with an infinite past, the idea that time must “pass” from a beginning moment all the way to the present seems false, since by definition such a universe has no beginning moment — Amalac
I said that the world exists and therefore has a necessary origin in time, is a tautology, a analytic truth. — Mww
world” and “universe" — Amalac
Argument A
1. It makes sense to ask about a time before any given moment in time — TheMadFool
2. If it makes sense to ask about a time before any given moment in time then, the past is infinite — TheMadFool
Ergo,
3. The past is infinite [1, 2 MP] — TheMadFool
Argument B
4. We are in the present, the now
5. If we're in the present, the now and the past is infinite then, the infinite past (has passed) is an actual/completed infinity — TheMadFool
You're bothered by how if the past is infinite, time has no beginning and ergo, you contend that time couldn't possibly pass. This, if you really think about it, is just another way of expressing the idea that the past is finite. — TheMadFool
In other words, there has to be a beginning for time = the past is finite. Simply put, a petitio principii - you can't claim the past is finite because the past is finite. — TheMadFool
As for the passage of time, we're here, in the now, right? Considering the past is infinite (see proof above) and we're here, in the now, time has passed. — TheMadFool
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