Physical implications of Kalām argument

[Dorfl]

This thread more or less instantly got derailed into a discussion of the Kalām cosmological argument. The argument—as I understand it—goes basically:

1. No infinite set can exist in the physical world.

2. Therefore, the universe cannot have existed forever.

3. Therefore, the universe must have begun at some point.

4. (A bunch of additional steps to show why this implies the existence of the arguers favourite creator god. Not very relevant to the science subforum.)

Whether the argument is sound or not is already being discussed in the other thread. What I wonder about is the physical implications that the premise #1 would have, if it were true. For example, it seems to imply that the universe is finite in both space and time—requiring a big crunch—and that space and time are both quantized.

Are there any other implications that #1 would have, and are they correct, as far as we know?

 

[Mashuna]

This thread more or less instantly got derailed into a discussion of the Kalām cosmological argument. The argument—as I understand it—goes basically:

1. No infinite set can exist in the physical world.

2. Therefore, the universe cannot have existed forever.

3. Therefore, the universe must have begun at some point.

4. (A bunch of additional steps to show why this implies the existence of the arguers favourite creator god. Not very relevant to the science subforum.)

Whether the argument is sound or not is already being discussed in the other thread. What I wonder about is the physical implications that the premise #1 would have, if it were true. For example, it seems to imply that the universe is finite in both space and time—requiring a big crunch—and that space and time are both quantized.

Are there any other implications that #1 would have, and are they correct, as far as we know?

Could you elaborate on why the universe being finite in space and time would require a big crunch?

 

[Dorfl]

Could you elaborate on why the universe being finite in space and time would require a big crunch?

At least, the universe would need to end somehow. Not necessarily through a Big Crunch, I admit, but time would need to be bounded in some way.

 

[Mashuna]

At least, the universe would need to end somehow. Not necessarily through a Big Crunch, I admit, but time would need to be bounded in some way.

As long as it's bound at the start (by the Big Bang), I don't understand why you'd need to have a defined end point. It's not like you can get to infinity by counting.

 

[Dorfl]

As long as it's bound at the start (by the Big Bang), I don't understand why you'd need to have a defined end point. It's not like you can get to infinity by counting.

I might be wrong, but it seems to me that even if I will obviously never reach t=∞, spacetime would still contain an infinite number of events, which would contradict #1.

 

[Mashuna]

I might be wrong, but it seems to me that even if I will obviously never reach t=∞, spacetime would still contain an infinite number of events, which would contradict #1.

I'm not sure either. I'm off to start counting events - I'll let you know how I get on.

<sets off to start his supertasks>

 

[Guybrush Threepwood]

I might be wrong, but it seems to me that even if I will obviously never reach t=∞, spacetime would still contain an infinite number of events, which would contradict #1.

I would have thought not, since at any point t=reallyreallyreallybig, you just wait for 1s and click your fingers, that's another event, so at t=reallyreallyreallybig there hadn't been an infinite number of events.

 

[Dorfl]

I'm not sure either. I'm off to start counting events - I'll let you know how I get on.

<sets off to start his supertasks>

Ask Chuck Norris to do it instead.

 

[Dorfl]

I would have thought not, since at any point t=reallyreallyreallybig, you just wait for 1s and click your fingers, that's another event, so at t=reallyreallyreallybig there hadn't been an infinite number of events.

Well, yes. But in any infinite countable set, any particular member is member #(A finite number). That doesn't mean the set is not infinite.

Note however that I have not formally studied set theory yet, so I may be talking out of my donkey.

 

[Mashuna]

Ask Chuck Norris to do it instead.

I only got as far as three hundred and forty six, then I got into trouble for doing my supertasks before I'd finished my normal tasks.

I reckon I was almost half-way through, so I estimate that there are no more than a thousand events in all of spacetime.





I've always been good at estimating.

 

[Dancing David]

At least, the universe would need to end somehow. Not necessarily through a Big Crunch, I admit, but time would need to be bounded in some way.

I don't know. The universe is not required to meet our expectations and thought constructs.

 

[Dancing David]

I would have thought not, since at any point t=reallyreallyreallybig, you just wait for 1s and click your fingers, that's another event, so at t=reallyreallyreallybig there hadn't been an infinite number of events.

Well in discussions of the Big Bang, the people who understand it talk about infinitity being spread in the 'smaller space' of the early universe. My eyes glaze over, but it would appear that the universe could be infinite.

 

[drkitten]

Whether the argument is sound or not is already being discussed in the other thread. What I wonder about is the physical implications that the premise #1 would have, if it were true. For example, it seems to imply that the universe is finite in both space and time—requiring a big crunch—and that space and time are both quantized.

Are there any other implications that #1 would have, and are they correct, as far as we know?

Well, as far as I know, #1 is a load of horse-pucky from beginning to end.

But in particular, I want to know what he thinks it means for a "set" to "exist in the physical universe." A set is an abstract concept, and we can easily have sets of other abstract concepts such as numbers. If he's suggesting that, for example, the set of all prime numbers isn't exist,.... well, put down that crack pipe, back away slowly, and no one gets hurt.

Having said this, there are a lot of apparently physical things that are also abstract. "The set of all places a penguin could be," for example.

So, no. I don't see #1 as demanding finiteness in either time or space. Our measuring system is not a part of the physical universe any more than our counting system is.

 

[ddt]

Well, as far as I know, #1 is a load of horse-pucky from beginning to end.

But in particular, I want to know what he thinks it means for a "set" to "exist in the physical universe." A set is an abstract concept, and we can easily have sets of other abstract concepts such as numbers. If he's suggesting that, for example, the set of all prime numbers isn't exist,.... well, put down that crack pipe, back away slowly, and no one gets hurt.

Having said this, there are a lot of apparently physical things that are also abstract. "The set of all places a penguin could be," for example.

Someone called?

So then, following your argument, there's a potentially infinite amount of places a penguin can be. But can there be actually an infinite amount of penguins? That is what the discussion of an "actual infinite" amounts to, as far as I understand.

So, no. I don't see #1 as demanding finiteness in either time or space. Our measuring system is not a part of the physical universe any more than our counting system is.

The wiki page on the Kalam cosmological argument mentions also that the following premise is needed:

A beginningless series of events is an actual infinite.

And from that, at least, I infer that time then should be quantized. The series of events:

the earth moves at t = 1 + 1/n​

is an actually infinite series which is beginningless.

 

[blutoski]

It seems like circular reasoning. Premise #1 is a claim, rather than a fact.

ie: "I don't believe the universe is infinite, because I don't believe real things can be infinite."

It's internally consistent, but it's not based on any externally verifiable facts. It's just the same claim reworded twice.

 

[drkitten]

So then, following your argument, there's a potentially infinite amount of places a penguin can be. But can there be actually an infinite amount of penguins? That is what the discussion of an "actual infinite" amounts to, as far as I understand.

Exactly. We might be able to agree that in principle there could only be a finite number of physical penguins, but an infinite number of potential or imaginary penguins, because our imagination is not physical.

The wiki page on the Kalam cosmological argument mentions also that the following premise is needed:

And from that, at least, I infer that time then should be quantized. The series of events:

the earth moves at t = 1 + 1/n​

is an actually infinite series which is beginningless.

That's just Zeno's paradox, and any of the standard resolutions apply.

 

[Dorfl]

I don't know. The universe is not required to meet our expectations and thought constructs.

Definitely not. My point is that #1 requires time to be bounded, implying an end to time. Not that anything #1 requires is actually the case.

 

[Dorfl]

It seems like circular reasoning. Premise #1 is a claim, rather than a fact.

ie: "I don't believe the universe is infinite, because I don't believe real things can be infinite."

It's internally consistent, but it's not based on any externally verifiable facts. It's just the same claim reworded twice.

Last I checked, this thread was at 18 pages and still discussing whether #1 is well-founded or not. What I was curious about is just the physical implications it would have, if it were true.

 

[Yoink]

Wow. If that Wikipedia page on the Kalam cosmological argument represents the argument accurately it's so trivial as not to be worthy of serious discussion.

Essentially it amounts to "it makes my brain hurt to think about infinitude, therefore the universe must have a beginning and I'm going to call that God." Like every other philosophical "proof" of God, an averagely intelligent eight year old could demonstrate its shortcomings.

Philosophical arguments for the existence of God prove only one thing: the horrible effect religious belief has on people's ability to reason. Otherwise intelligent, even brilliant, people will suddenly become obstinately fixated on the most puerile and pathetic arguments simply because they support their religious prejudices. Sad.

 

[Dorfl]

I only got as far as three hundred and forty six, then I got into trouble for doing my supertasks before I'd finished my normal tasks.

I reckon I was almost half-way through, so I estimate that there are no more than a thousand events in all of spacetime.

I've always been good at estimating.

I was going to build a robot to count the first hundred events, after itself building another robot which could count the next hundred twice as fast, after building a robot in half the time that counted four times as fast...

But I'll accept your estimate. It sounds reasonable.