Infinite Past

[Speakpigeon]

Do you think that the idea that the past might be infinite is a logical contradiction because by definition the past ends with the present moment?
EB

 

[Random Person]

Do you think that the idea that the past might be infinite is a logical contradiction because by definition the past ends with the present moment?
EB

No. The argument is that the "present" moment would never arrive because an infinite number of moments would have to occur prior to this one.

 

[Kharakov]

There are an infinite number of moments between now and 1 second ago, assuming a non-granular time. There might be a finite number of well defined thoughts and forms between now and 1 second ago, but AFASIAIOK, spacetime is smooth, not granular, which means it can be divided into any number of pieces we desire.

 

[untermensche]

There are an infinite number of moments between now and 1 second ago, assuming a non-granular time. There might be a finite number of well defined thoughts and forms between now and 1 second ago, but AFASIAIOK, spacetime is smooth, not granular, which means it can be divided into any number of pieces we desire.

If there are an infinite number of moments between now and 1 second then we will never get there.

For time to advance it must be discreet, quantized.

 

[PyramidHead]

No matter which way you look at it, the issue ends in an absurdity. If the past is infinite, then it seems hard to fathom how it would have ever become the present. Yet, if the past is bounded, we have to claim there was a first event, itself uncaused, that set everything in motion.

Both objections can be mitigated somewhat by treating time as a dimension just like any of the spatial dimensions. The universe would thus be a large object with x, y, and z dimensions that we can visualize roughly as a 3-D structure, but also with a t dimension representing time. At every point on the t axis (which we are unable to visualize) is a slice of the 3-D universe at a particular moment. One of those slices corresponds to what we call the present while the others correspond to either the past or the future. But those labels are a consequence of our subjective perception of the flow of time; in reality, all points on the t axis are equally prominent. Just as there is no center of the universe in spatial terms, there is no privileged coordinate in temporal terms.

Having reduced time to a dimension like length or width, the question of an infinite past becomes no different than the question of infinite space. If someone suggested the universe was infinitely wide, we wouldn't say "that's impossible, because then someone would have to traverse an infinite distance to get here." This is because we do not experience space as constantly advancing as we experience time. So, I think an infinite past is not refuted by the objection that an infinite number of moments would have needed to happen before now, as if now would somehow "never arrive" in that case. But if time is just another dimension, there is no privileged "now" that all past events are striving towards--it's just points on a number line.

This doesn't even get into the possibility of time curving back on itself, as has been suggested for space in a number of different manifolds. So, I think the issue is simply not something we can solve by logic alone, since the universe at its extremes may be illogical.

 

[Kharakov]

There are not an infinite amount of finite length segments in a line segment. There are an infinite amount of points on a line segment.

Since the present is a point rather than a segment, there are an infinite amount of previously present points in the past between now and 1 second ago.

 

[untermensche]

There are not an infinite amount of finite length segments in a line segment. There are an infinite amount of points on a line segment.

Since the present is a point rather than a segment, there are an infinite amount of previously present points in the past between now and 1 second ago.

A point is not real.

Spacetime is.

 

[untermensche]

Do you think that the idea that the past might be infinite is a logical contradiction because by definition the past ends with the present moment?
EB

No. The argument is that the "present" moment would never arrive because an infinite number of moments would have to occur prior to this one.

That's exactly the argument.

Not too hard to understand.

If one had to take infinite steps before one arrived one would never arrive.

 

[PyramidHead]

Who or what is the "one" that would have to take an infinite number of steps, if we're talking about time?

 

[untermensche]

Who or what is the "one" that would have to take an infinite number of steps, if we're talking about time?

An infinite number of discreet moments is equivalent to an infinite number of steps.

It is an analogy.

But something many people can clearly understand.

 

[beero1000]

The passage of time is measured between moments and every moment in time is a finite amount of time from right now. It still does not follow from that that the past is bounded.

Saying 'an infinite amount of time must have passed before now' implicitly tries to measure time 'from the beginning', presupposing the conclusion.

 

[untermensche]

The passage of time is measured between moments and every moment in time is a finite amount of time from right now. It still does not follow from that that the past is bounded.

Saying 'an infinite amount of time must have passed before now' implicitly tries to measure time 'from the beginning', presupposing the conclusion.

No measurement involved.

If we stop time at some moment, infinite time in the past would mean that infinite moments have already passed.

Infinite moments is moments without end.

They cannot already have passed.

 

[PyramidHead]

Who or what is the "one" that would have to take an infinite number of steps, if we're talking about time?

An infinite number of discreet moments is equivalent to an infinite number of steps.

It is an analogy.

But something many people can clearly understand.

There are two situations we're talking about here. The first is just Zeno's paradox. Between now and 1 second from now, you could theoretically subdivide time indefinitely so there are an infinite number of theoretical subdivisions. So, since you would never finish taking an infinite number of steps, you'd never get to 1 second from now. That's bullshit though, because it took at least 2 seconds to read this paragraph and here we are.

But the other situation, the topic of this thread, is different. It isn't asking if there's an infinite number of points between A and B, it's asking if there is an A at all (A being the beginning of time). If there is no A, then it doesn't make sense to say "someone would have to cross an infinite number of steps between A and B".

Think of an infinitely tall building. You couldn't say it's impossible because someone would need to descend an infinite number of floors to get from the top to the bottom, because there is no top. By definition, any floor of an infinitely tall building is a finite number of floors from the bottom. In the same way, any point in an infinite past is a finite number of seconds from now.

So, nobody would have to traverse an infinite number of steps to get to now after all. If you disagree, then you should be able to identify the point in the past that is an infinite number of seconds away from the present. But there isn't one, because all points in the past are a finite number of seconds from now.

- - - Updated - - -

The passage of time is measured between moments and every moment in time is a finite amount of time from right now. It still does not follow from that that the past is bounded.

Saying 'an infinite amount of time must have passed before now' implicitly tries to measure time 'from the beginning', presupposing the conclusion.

No measurement involved.

If we stop time at some moment, infinite time in the past would mean that infinite moments have already passed.

Infinite moments is moments without end.

They cannot already have passed.

It's no different from height. An infinitely tall building doesn't imply that someone needs to descend all the way to the ground floor from a floor infinitely high. If the past goes on infinitely, we're just at the base of the building looking up.

 

[untermensche]

We don't live in Zeno's paradox. We can move because space is not infinite. It is discreet.

Time passes because it is discreet, quantized, not infinite.

And talking about imaginary points that can have no dimension is talk for introductory calculus, not talk for a discussion about reality.

Thinking Spacetime, one does not exist without the other, is quantized is certainly in keeping with current understandings where other phenomena are seen to be quantized.

 

[untermensche]

Think of an infinitely tall building. You couldn't say it's impossible because someone would need to descend an infinite number of floors to get from the top to the bottom, because there is no top. By definition, any floor of an infinitely tall building is a finite number of floors from the bottom. In the same way, any point in an infinite past is a finite number of seconds from now.

This is not an issue of climbing or descending a few steps in an imaginary building. It is a claim that one has already climbed all the steps.

If we stop time at a moment there could not have been infinite moments before it.

Infinite moments are also imaginary but they are moments without end.

Moments without end could not have passed prior to some moment.

 

[Phil Scott]

There are not an infinite amount of finite length segments in a line segment. There are an infinite amount of points on a line segment.

To clarify: there are not an infinite amount of line segments of the same length in a line segment. It's pretty trivial to prove that if the line segments have different length, there can be infinitely many of them, though this may seem counterintuitive on first glance.

 

[PyramidHead]

Think of an infinitely tall building. You couldn't say it's impossible because someone would need to descend an infinite number of floors to get from the top to the bottom, because there is no top. By definition, any floor of an infinitely tall building is a finite number of floors from the bottom. In the same way, any point in an infinite past is a finite number of seconds from now.

This is not an issue of climbing or descending a few steps in an imaginary building. It is a claim that one has already climbed all the steps.

Right, climbed down them all to get to the bottom, where we are standing right now. Is an infinitely tall building impossible for that reason?

If we stop time at a moment there could not have been infinite moments before it.

Infinite moments are also imaginary but they are moments without end.

Moments without end could not have passed prior to some moment.

Why not? What would things look like if an infinite number of moments had passed before the present? Would we still be in the past? If you can't even conceive of the empirical consequences of your statement, does that tell you anything?

 

[untermensche]

This is not an issue of climbing or descending a few steps in an imaginary building. It is a claim that one has already climbed all the steps.

Right, climbed down them all to get to the bottom, where we are standing right now. Is an infinitely tall building impossible for that reason?

You can't claim you climbed ALL the stairs unless you start from the bottom and climb ALL of them.

Since there is no top you obviously can't start there.

What would things look like if an infinite number of moments had passed before the present?

Infinite moments are moments without end.

Something without end cannot have already passed.

 

[PyramidHead]

Right, climbed down them all to get to the bottom, where we are standing right now. Is an infinitely tall building impossible for that reason?

You can't claim you climbed ALL the stairs unless you start from the bottom and climb ALL of them.

Since there is no top you obviously can't start there.

In the analogy, the bottom is the present. The infinite height of the building is the infinite past. Think about what you just said and how it proved my point.

What would things look like if an infinite number of moments had passed before the present?

Infinite moments are moments without end.

Something without end cannot have already passed.

Passed since when?

 

[untermensche]

In the analogy, the bottom is the present. The infinite height of the building is the infinite past. Think about what you just said and how it proved my point.

Then the analogy does not fit the case.

The claim is that at any given moment infinite moments have already occurred. Infinite time has already passed.

It would be equivalent to somebody claiming that before a given moment ALL the infinite stairs have already been climbed.

Something without end cannot have already passed.

Passed since when?

It's a contradiction. A thing that passes without end (infinite time) cannot have already passed.