I have no theory on offer, but I have never assumed that time was anything much more than a human construct to help us make sense of and order our version of 'reality'. Notions of cause and eternity similarly are ideas we use to explain things and to some extent map onto terrestrial events as we view them.

,

I voted no, I'm suspicious of this line:

Therefore, since the moment is both a beginning and an end, there must always be time on both sides of it.

The interval of real numbers (1,2) has 'no number on the right', as it does not contain its least upper bound ( 2 ), you'd need to look 'outside of it' (in the real numbers themselves) to get that. So in that interval you get a length (moment = length of time?) with no first largest time point within it... The only way to give that interval a maximum is to bring the real numbers themselves (an underlying continuum) into the picture. In effect, this conjures the eternity of time 'the moment' is embedded in into the moment, without showing that such an operation is valid.

To me it looks like three different duration concepts being conflated with each other - bounded intervals, intervals which don't contain their end, and the underlying set that end exists in.

I doubt these concepts are as Aristotle intended them to be interpreted, though. Maybe his argument is valid when understood closer to his own terms.

@Kuro,

To be completely honest, I am not sure if I agree or disagree. By "time never beginning", I am interpreting him to be positing an actual infinite, which, in that case, I would disagree. However, if he is stating that time is potentially infinite, as in change (and subsequently causality) is potentially infinite, then I agree. I haven't read up enough of on Aristotle, I do admit. Maybe you know which he is referring to? Likewise, I interpret "eternal" as "unchanging with respect to any notion of time/change", which is also (I would say) subjected to my same dilemma as previously depicted (potentially eternal or actually eternal?).

Obviously, time had a beginning. If not, the universe would be in the chaotic, fleeting state of chaos, accelerating away towards infinity. The universe would be a dull place where nothing happened. This is a consequence of thermodynamics and initial conditions. Time could have evolved in the other direction, but then it would have an end at t=0.

The beginning of unidirectional time is easily set in motion by the virtuality going forward and backward in time. From this central virtuality, matter and time can be created over and over again. So time has infinite beginnings. After present time ends at infinity, a new time starts. Aristotle was right about one thing though. His eternal circular motion resembles the fluctuating time constituted by the virtuality at the source.

So if the universe changes from "no-time" to "time", that in of itself is a temporal process, making it necessary that "no-time" is actually time. So time never begins. — Kuro

This bothers me. Time count begins when something changes. A void with no space-time has no time. Time starts at the mark of a change. "Universe and no-time" don't go together.

Time never Begins!

Yep. Why? Refer to Zeno's paradox(es): Achilles, forget about catching up with the tortoise, couldn't even start (running [clock])! Time (is an illusion)? :chin:

I voted no, I'm suspicious of this line:

Therefore, since the moment is both a beginning and an end, there must always be time on both sides of it. — fdrake

I agree with this. I also challenge the claim that motion defines time. It does not. Motion makes time measurable, but it does not define it. Time exists outside of motion.

What Aristotle proved is not that time exists forever, but that motion has existed forever. He fails to see the power and the finding of his own proof.

Aristotle's argument is incoherent as it consists of attributing temporal-predicates ("before", "after", "beginning", "becoming" ...) to "time" itself which begs the question insofar as temporal-predicates presuppose "time".

Further, how can there be any 'before' and 'after' without the existence of time? Or how can there be any time without the existence of motion? If, then, time is the number of motion or itself a kind of motion, it follows that, if there is always time, motion must also be eterna

This argument fails if time is assume to go forward only. If it goes up and down, as before the unidirectional inflation, spawning the real from the virtual, time can have a beginning. As it must have a beginning. If this weren't the case, we would observe chaos only.

I agree with this. I also challenge the claim that motion defines time. It does not. Motion makes time measurable, but it does not define it. Time exists outside of motion. — god must be atheist

Time can't exist without space. Your conception of time makes you think it can go one direction only. But it can go up and down. It can oscillate. In fact, the vacuum is oscillating in time.

I voted no as time may not be linear.
Can you perceive of a lifeform who experiences existence, not as a continuum?
A lifeform which 'hops' (@EugeneW) between the linear existence of other lifeforms such as us.
It moves between linear consciousnesses, not at will but based on the laws of physics of its own multidimensional space/multidimensional time. It learns from each encounter with linear time corporeal lifeform like us and it also experiences 'periods of continuum' within its own spatial dimensions, where it can interact with its own kind and experience and build within its own world, before it 'phase shifts' again.
Did I just create this lifeform in a mimicry of the god posit by thinking about its existence or am I just thinking like an arrogant theist?

Obviously, time had a beginning. If not, the universe would be in the chaotic, fleeting state of chaos, accelerating away towards infinity. — EugeneW

What if there is more to the universe than there appears to be? What if there is more than one universe?

Time can't exist without space. — EugeneW

Time cannot exist without change.

This argument fails if time is assume to go forward only. If it goes up and down, as before the unidirectional inflation, spawning the real from the virtual, time can have a beginning. As it must have a beginning. If this weren't the case, we would observe chaos only. — EugeneW

In other words things change relative to each other. The relationship between one change and another is time.

Time cannot exist without change — Harry Hindu

But only in space they can change.

In other words things change relative to each other. The relationship between one change and another is time. — Harry Hindu

In other words, things can oscillate in time, like virtual particles in the vacuum, or have a timelike direction, like virtual particles turned real.

Do you think Aristotle's argument is sound or valid? Why or why not? — Kuro

You can tell this is a good topic by all the thoughtful answers you got. Not a smarty pants in the bunch. I like quoted text a lot. Is it convincing? Yes, actually it is. Does it convince me? Well.... I'm with @Bob Ross "To be completely honest, I am not sure if I agree or disagree." So, I agree that I can't decide if I agree or not.

I have never assumed that time was anything much more than a human construct to help us make sense of and order our version of 'reality'. Notions of cause and eternity similarly are ideas we use to explain things and to some extent map onto terrestrial events as we view them. — Tom Storm

I agree with this, but I also find the argument convincing. Does that mean that I've violated the Law of Noncontradiction? So..what are you going to do about it?

The interval of real numbers (1,2) has 'no number on the right', as it does not contain its least upper bound ( 2 ), you'd need to look 'outside of it' (in the real numbers themselves) to get that. — fdrake

Aristotle says that time must be eternal, not that sequences of numbers must be. Numbers are ideas. while time is real. Except that it isn't. See above.

Time count begins when something changes. A void with no space-time has no time. Time starts at the mark of a change. "Universe and no-time" don't go together. — L'éléphant

Agree.

I also challenge the claim that motion defines time. It does not. Motion makes time measurable, but it does not define it. Time exists outside of motion. — god must be atheist

Disagree, although I might say "change" instead of "motion."

Time cannot exist without change. — Harry Hindu

In other words things change relative to each other. The relationship between one change and another is time. — Harry Hindu

Agree.

This is fun.

I think what Aristotle is doing is similar to what Kant does with the antinomies. He is not arguing to a conclusion that will resolve the issue one way or another. He is, rather, laying out arguments that point to the limits of reason. The arguments lead to aporia.

But he is well aware of the danger of leaving such questions open. Others will rush in to proclaim the "truth".

As Al-Farabi notes:

Whoever inquires into Aristotle’s sciences, peruses his books, and takes pains with them will not miss the many modes of concealment, blinding and complicating in his approach, despite his apparent intention to explain and clarify.

(Harmonization) Quoted in David Bolotin's "Approach to Aristotle’s Physics".

Do you think Aristotle's argument is sound or valid? — Kuro

The phrase "Aristotle's argument is correct" is incorrect.

A sound argument has a different meaning to a valid argument.

There should be four questions within the poll:
Aristotle's argument is sound
Aristotle's argument is not sound
Aristotle's argument is valid
Aristotle's argument is not valid

Aristotle's argument is valid but not sound.

His premise is false - "Now since time cannot exist and is unthinkable apart from the moment, and the moment a kind of middle-point, uniting as it does in itself both a beginning and an end, a beginning of future time and an end of past time"

His reasoning is correct

His conclusion is false - "it follows that there must always be time"

There is a problem with Aristotle's premise

We can only experience the moment we are in. We cannot experience at this moment either the moment before this moment or the moment after this moment. Therefore, we can never directly experience either the past or the future.

Therefore, as we can never directly experience either the past or the future, we can never have first hand knowledge of the meaning of the terms time, past, present, eternal, creation or motion.

Therefore, Aristotle's conclusion that time and motion are eternal can only ever be an interesting hypothesis.

Do you think Aristotle's argument is sound or valid? Why or why not? — Kuro

I think it's valid with the premise that time accords with the way we usually imagine it.

But there are other ways to imagine it and maybe some ways we haven't considered yet (as a species). So the conclusion may be wrong.

I choose the wrong option. Aristotle is correct. Time needs a first kick to take off in one direction. His eternal rotational motion comes in a modern package. The eternal rotational motion of virtual particles in the vacuum. These particles were the only available ones before the universe took of in a blaze of inflation. The particles fluctuated (rotated) in time on the singularìty. When the circumstances, determined by a preceding temporally unidirectional universe, were right, the starting sign said all systems to go. To take off in one direction. So the fluctuating time of the virtual became the unidirectional of the reals. Note that time, cause, and effect, could have gone in the opposite direction as well. Which means, a universe collapsing from infinity towards the singularity, disappearing in it, and setting a new universe in motion at infinity. But the gods were lazy and liked forward, normally causative motion. They throw a ball after thinking about it.

I got almost the same as RussellA

time cannot exist and is unthinkable apart from the moment, and the moment a kind of middle-point, uniting as it does in itself both a beginning and an end

The first claim is:

1. For any point in time t, there exists a time t1 such that t1 is before t and there exists a time t2 such that t2 is after t.

....it follows that there must always be time: for the extremity of the last period of time that we take must be found in some moment, since time contains no point of contact for us except the moment. Therefore, since the moment is both a beginning and an end, there must always be time on both sides of it.

The second claim is:

2. If time began, then 1. is false.

Why should we accept 1? If 1 is true it follows that time did not have a beginning. Conversely, if time did have a beginning, then 1 is false. But since the question at issue is whether time did have a beginning, then the argument begs the question.

There is also the problem 180 pointed out. We can talk about processes having a beginning and an end in time. But it's doubtful whether it is coherent to talk about time itself having or not having a beginning or end in time.

However, Aristotle was not liable to make simple mistakes in reasoning. His writings are condensed, sometimes almost lecture notes. There may be more to this. For example:

3. If 1 is false, then we cannot think or speak coherently about time. ("unthinkable")

4. We are now communicating with each other coherently about time.

So 1 is necessarily true.

The necessity in question is that our idea of time falls apart if we try to think of a time before which there was no time. Aristotle may be closer to 180's objection than it seems.

Time exists outside of motion — god must be atheist

How can the clock tick without motion?

Let me point out first that the arguments of 180booze should not be taken to seriously. — EugeneW

Let it be that time is constituted by collective motions of particles. Let is also be that time can be understood in terms of before-and-after processes but that time itself is not one of those processes. And let it be that time is an affect of motion - that motion is what makes time what we understand it to be. It seems to me that EugeneW, 180 Proof and Aristotle are not so far apart after all.

We can't blame him though. — EugeneW

True enough. You can't patronise a person for being alcoholically incompetent and at the same time hold them responsible for their actions. But that's another thread.

Let it be that time is constituted by collective motions of particles. Let is also be that time can be understood in terms of before-and-after processes but that time itself is not one of those processes. And let it be that time is an affect of motion - that motion is what makes time what we understand it to be. It seems to me that EugeneW, 180 Proof and Aristotle are not so far apart after all — Cuthbert

I think thermodynamic time Is constituted the irreversible processes. You can quantify these processes by putting a clock besides them. A clock is an ideal process though. Only in our minds a truly periodic motion (with constant period time) exists. And of this clock, say a pendulum, you can't say it goes forwards or backwards in time. That's exactly the case with virtual particles. They fluctuate in time. When the circumstances are right, this fluctuation is turned into unidirectional real-particle time. Everywhere in empty space, virtual particles fluctuate in time. Before inflation, virtual particles were the only players around. So all what was present was a kind of virtual real ideal clock, without yet processes to measure time of. The events of a faraway universe accelerating towards infinity were the trigger of thermodynamic time. Not sure what 180 says about this. @180 Proof, what's your idea?

The presupposition underlying much of this argument is the same one underlying Rasmussen's paradox. An early formulation of this presupposition is found in Parmenides claim:

To think and to be is the same.

It is the height of human hubris and folly to think that what is, was, and will be are limited by what we can think or comprehend or can give an account of.

But it's doubtful whether it is coherent to talk about time itself having or not having a beginning or end in time. — Cuthbert

Thermodynamic time has a beginning by necessity. Forward time is determined by collective particle motions evolving towards higher entropy. If time had no beginning it logically follows that the current state of the universe was one of chaos simple and pure. That, we observe not, fellophilo's.

So, time had a beginning. But how can it begin without a kick? The modern-day physical ideas offer a solution. Before thermodynamic arrow of time shot, the bow was tense. The arrow consisted of virtual particles, a much debated idea in modern physics, actually close to Aristotle's idea of eternal circular motion. All basic virtual particles oscillate in time. Or better, they constitute
oscillating time. Real particles in motion interact by means of these eternal omnipresent virtual particles, and these constitute the time we're used to.

:up:

:eyes:

'Time' is a metric of asymmetric change (i.e. physical transformations) ... — 180 Proof

No asymmetric changes, no clocks. :point:

'Time' is a metric of asymmetric change (i.e. physical transformations) ... — 180 Proof

I hate to say it, let alone admit it... but this is a very... eeeh... a very... go... eeeh, damn... go... go... go..., excuse the stutter, booze. I sing it: this is a very gooood idea! Realistic even.

No asymmetric changes, no measurable time. — 180 Proof

No asymmetric changes, no measurable time. — 180 Proof

:down: ,eeeehh... :point: ,eeeeh :up:

You got a point! I merely add that the pre-big-bang-inflation symmetric time was not measurable indeed because it actually was a clock.

It is the height of human hubris and folly to think that what is, was, and will be are limited by what we can think or comprehend or can give an account of. — Fooloso4

To think what was, is, and will be is limited is a conjecture which can be experimentally verified. All current evidence points at an unlimited succession of time intervals [0,inf.). Every ending of an interval kicks the virtual, omnipresent, eternally fluctuating basis into reality, thereby creating a new [0,inf.) interval of time. In the by now famous words of @butimfeeling2022: "over and over again".