Regarding the infinite past, I heard a good riddle: if a clock has existed forever, what time would it show this moment?

This is a good one.

It would need to show some time, undoubtedly. But how do we know how it was set, if it was never set? Remember, it had no beginning, no manufacturing date. It has existed for ever. It shows some time, as it is a regular clock. What is the time it shows?

Yeeee-haaaw! — god must be atheist

Yes, ostensibly a clock that has always been ticking cannot exist. How about the infinite number of red books and infinite number of black books, that when added together total the same amount of books as just the red books. And the planets orbiting the sun at different speeds, but making the same amount of orbits, even if you suddenly sped the faster one up further.

The answer to my poll question is not as obvious as some people think it is?

Create means "bring something into existence". This cannot be done for something that has always existed. — Down The Rabbit Hole

Why not? — Raymond

Having always existed means it didn't start to exist.

Talk of totals assumes finitude - to say the planets total the same number of orbits you need finite numbers to compare; instead it seems right to say that one planet has always done more orbits than the other; it’s only if they were finite that at any point they could have done the same number.

Dear rabbit, I have personally written a blog or two and collected and published data on the topic (non-being) of nothing. You may also find L.M. Krauss "A Universe from Nothing" an intriguing read.

I have not learned much from reading three pages of comments on here. I will tell you my vote is that time is perpetual and infinite in both directions.

Our newest Telescope, Webb's, will reveal more about the nature of time and the beginning of our universe (cosmology). . — Josh Alfred

The trouble is, we don't have any experience with "nothing" in the literal sense. What evidence have we got to say things don't just pop into existence out of nothing?

The title of the book should be "A Universe from Quantum Fields". I think he said in interviews that "A Universe from Nothing" was a sales trick.

But still... The eternal can be created from outside of spacetime.

Talk of totals assumes finitude - to say the planets total the same number of orbits you need finite numbers to compare; instead it seems right to say that one planet has always done more orbits than the other; it’s only if they were finite that at any point they could have done the same number. — AJJ

For punch I added "even if you suddenly sped the faster planet up further". It is absurd that both planets would have done the same amount of orbits?

Speed one up all you like. I’m saying talk of them doing the same number of orbits assumes finitude - if they’ve been going forever there is no total number of orbits to compare. The most you could say is that, given any stretch of time within that infinity, one planet has invariably done more orbits than the other.

Speed one up all you like. I’m saying talk of them doing the same number of orbits assumes finitude - if they’ve been going forever there is no total number of orbits to compare. The most you could say is that, given any stretch of time within that infinity, one planet has invariably done more orbits that the other. — AJJ

I understand what you are saying; a total number of orbits and infinite orbits are incompatible. It still seems absurd that any extra orbits we suddenly add to one planet over the other actually adds nothing.

I’m not sure I’d call it absurd, because what you’re identifying again is simply that there isn’t a total to be added to, which given an infinite past is necessarily so. We can still say that one planet does so many orbits per year and the other does this many; in this light the lack of a grand total for each seems something to be accepted as necessary and unimportant.

I'm not sure where your preoccupation with number of periods of planets? If you increase the number of the revolutions of one planet in particular, what's the problem?

I’m not sure I’d call it absurd, because what you’re identifying again is simply that there isn’t a total to be added to, which given an infinite past is necessarily so. We can still say that one planet does so many orbits per year and the other does this many; in this light the lack of a grand total for each seems something to be accepted as necessary and unimportant. — AJJ

Okay, so you're saying Al-Ghazali's orbiting planets are unintuitive but not logically impossible?

Sorry to move the goalposts, but what if instead of the orbiting planets it's an infinitely ticking clock. What time would it show?

Sorry to move the goalposts, but what if instead of the orbiting planets it's an infinitely ticking clock — Down The Rabbit Hole

Ah! It's here that you make a wrong assumption. There is no clock tic-tac-ing eternally. Only an infinite sequence of clocks taking of from perfect clock states. The universe is eternal but there is an infinite succession of beginnings in time. An infinite eternal universe isn't a physical possibility. If there were no point zero in time life could not develop. It would be a time and spaceless universe devoid of matter. I.e. a nothing.
The steady state universe enjoyed some popularity but was not tenable.

Earlier in the thread I gave this response to the clock example:

It’s necessarily impossible to say what time it would show, precisely because it’s an infinite clock. If you saw it and it read 12 o’clock then the explanation for that would be that it said 11 o’clock an hour ago and 10 o’clock the hour before that, and there would be nothing more to it. — AJJ

It strikes me that in neither case (the planets and the clock) is there a logical problem. It’s just that there are things missing or that you can’t do given the nature of infinity.

It strikes me that in neither case (the planets and the clock) is there a logical problem. It’s just that there are things missing or that you can’t do given the nature of infinity. — AJJ

The thing missing is an initial state. Time needs an initial state and is irreversible because any state cannot serve as a begin state for the reversed process. There are two types of time. Coordinate, clock time, an imaginary for i entropic time, and the real (reversible) clock time, in which entropic time is still absent, the pre-inflationary state of our 3D universe on the 4D substrate space.

Having always existed means it didn't start to exist. — Down The Rabbit Hole

But still... The eternal can be created from outside of spacetime. — Raymond

I didn't say always in time. If it was created, it began to exist.

I'm not sure where your preoccupation with number of periods of planets? If you increase the number of the revolutions of one planet in particular, what's the problem? — Raymond

I'm not obsessed with orbiting planets y'know :lol: It's Al-Ghazali's example, that I've brought up a couple of times in these 5 pages and responded to criticisms of. It's unintuitive (at the least) that despite speeding the orbits of one planet over the other, it never actually orbits more. Although as @AJJ has said it's not clear that it's impossible.

Ah! It's here that you make a wrong assumption. There is no clock tic-tac-ing eternally. Only an infinite sequence of clocks taking of from perfect clock states. The universe is eternal but there is an infinite succession of beginnings in time. An infinite eternal universe isn't a physical possibility. If there were no point zero in time life could not develop. It would be a time and spaceless universe devoid of matter. I.e. a nothing.
The steady state universe enjoyed some popularity but was not tenable. — Raymond

The ticking of a clock is an example to test an infinite chain of events (in this case the infinite ticks). Each of the "infinite succession of beginnings in time" you refer to is like the tick of a clock.

The ticking of a clock is an example to test an infinite chain of events (in this case the infinite ticks). Each of the "infinite succession of beginnings in time" you refer to is like the tick of a clock. — Down The Rabbit Hole

I don't refer to each tick as beginning of a new chain. I refer to beginnings in time for each new big bang. Suppose a big bang starts of like a 3D closed spatial structure on an infinite 4D substrate. When the two 3D structures have accelerated away towards the infinities on the 4D structures, conditions are set at the origin on the 4D substrate for two mirrored 3D universes to break free from the real, reversible perfect clock state. This state is a Planck sized 3D volume going back and forth , hence the perfect clock state. Then again, entropic time starts, not from t is zero but from the the slightly bigger Planck time (about 10exp-43 seconds). Again, two universes (matter/antimatter) are existent. The matter in these 3D pair can accelerate away again on the 4D substrate space (dark energy!). And again conditions are set at the origin of the 4D mouth to "shout" two new universes into existence. And again (entropic) time starts at about t=0 (slightly more actually, but precisely enough not to cause trouble).

Although this infinite series of bangs runs into the paradoxes, it might be the most plausible option. Sir Roger Penrose seems to think so. — Down The Rabbit Hole

Aristotle started the trend by pointing out that the world cannot possibly have been created out of nothing, and hence must be eternal. Since then many philosophers and scientists have thought the same. The opposite idea of a begining to the universe has more often been sported by religious institutions. When Georges Lemaître started to speak of a cosmic egg in the 20's, some chalked it up to his catholicism.

Aristotle started the trend by pointing out that the world cannot possibly have been created out of nothing — Olivier5

It's like the concept of charge nowadays. Charge is the cause of motion and it can be pure consciousness, or an fundamental form of it. His notion of the eternal circular motion is the predecessor of the modern concept of the ideal clock, which was the actually the pre-inflationary state of the universe. Add his pre quantum physics... Artistotle, my man!

That's also extremely dishonest to use the quote function to attribute to someone something they never said- reported, btw — Seppo

You are right, I apologize.

It’s necessarily impossible to say what time it would show, precisely because it’s an infinite clock. If you saw it and it read 12 o’clock then the explanation for that would be that it said 11 o’clock an hour ago and 10 o’clock the hour before that, and there would be nothing more to it. — AJJ

How about an infinity ticking stopwatch? Any number it shows would contradict its infinite ticks?

You’re right, but does the contradiction make impossible an infinite past or just an infinite stopwatch? I’d say the latter, since a stopwatch doesn’t run in cycles so its count necessarily has a beginning.

I’d say the latter, since a stopwatch doesn’t run in cycles so its count necessarily has a beginning. — AJJ

Actually, a stopwatch is the ultimate example of a cyclic process.

Is it? They don’t go in circles like a clock does; they keep ascending from 0 and left alone they never go back to the beginning.

That's true. But so does the clock. Every tick it goes a step further. The hand return to the beginning, but that's a matter of convenience. Beneath both ticks there hides a periodic process. Which is equivalent to a circular motion. These, by the way, are never truly periodic. Even the atomic clock is not perfect. The time that can't be eternal is entropic time. This time needs a beginning.

Artistotle, my man! — Raymond

Odd that he's mentioned only now, for a discussion that he started.

Yes indeed! I think even Einstein, Galileo(i?), Newton, Hamilton, Lagrange, Hawking, or you and me (to name a few in arbitrary order), owe him (or not, depending on your POV). His thoughts about time, primal movers, eternal circular motion, can compete easily with contemporary notions of space and time. Okay, he didn't use math that much, if at all. I think though that math covers up understanding of the true nature of time (and space).

Aristotle, Aristotle
Left without you
Would be lurking the bottle
Could no more make do

Would be rigid-stuck
In Einstein's arse
On his objective clock
That bugger parse

Aristotle Aristotle
You embottle
modern rebottle
Full throttle

Aristo my man
Far you are in space and time
Still I know I can
Not go on without you

You’re right, but does the contradiction make impossible an infinite past or just an infinite stopwatch? I’d say the latter, since a stopwatch doesn’t run in cycles so its count necessarily has a beginning. — AJJ

I don't know if you've read the book, but this was the response I gave when asked about Oppy's Philosophical Perspectives on Infinity:

"A lot of the classical actual infinity thought experiments he has answers for, but for those he doesn't he asserts that just because certain actual infinity thought experiments are impossible, it doesn't mean actual infinities are impossible. He points out that even finite scenarios can be impossible".

I think you are right that although the conclusions are counter-intuitive, they are not necessarily impossible.

Something from literally nothing is counter-intuitive. Necessarily Impossible?

I haven’t read that book, but my thinking is influenced by the kinds of things I’ve heard him say in the discussions I’ve listened to, which fit with what you’ve described in your quoted response there.

And it’s actually from what Oppy has to say about chance that I don’t think something from nothing is necessarily impossible. He calls chance a brute contingency: A and B are possibilities, A happens instead of B and there’s no explanation why (because if there was it wouldn’t be a chance occurrence). So it strikes me that if chance is real then it’s an example of something coming from nothing, and it’s happening all the time.

I think its harder to think of something coming from nothing than a infinite past because time could be a big circle. at least I can visualize It.

Yes, ostensibly a clock that has always been ticking cannot exist. — Down The Rabbit Hole

I don't get it. Why can't it exist? What is it in its supposed eternal ticking that makes it impossible to exist?