Max Tegmark's infinite universes

[Eos of the Eons]

You built the computer outta stardust on some distant planet? Go back.

 

[athon]

We could also be a butterfly's dream. Lots of things can be speculated. Determining which ideas should we spend time considering seriously and which we put aside for daydreams and fiction is why we have science.

Athon

 

[Norm Breyfogle]

noncontradictory?

And, again, I'm being entirely serious here. Anything you can describe in noncontradictory fashion exists somewhere in Tegmark's multiverse.

- drkitten

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How can you say that a Count Chocula universe is describable without contradiction? If there were no humans or tastebuds to taste it, in what consistent sense could it be said that it was Count Chocula at all? This kind of reasoning flaw permeates many such straw man arguments against the concept of an infinite multiverse.

The strongest argument for a multiverse of which I'm aware is based upon the extreme unlikelihood of our present universe among all the others which might exist, combined with quantum indeterminacy and the meaning of the quantum wave function collapse. As an earlier poster indicated, Occam's razor could be construed to suggest a multiverse as the "simplest" answer to many such questions.

 

[PogoPedant]

You know, there's a perfectly cromulent thread you already started on this topic.

The answer was "no" in that thread.

It's still "no" in this thread. I'm sure it will be "no" in the next thread you start, until you get sanctioned for spamming.

... and then it'll be "yes"?

 

[sol invictus]

How can you say that a Count Chocula universe is describable without contradiction? If there were no humans or tastebuds to taste it, in what consistent sense could it be said that it was Count Chocula at all?

By its chemical composition? I don't get your point.

This kind of reasoning flaw permeates many such straw man arguments against the concept of an infinite multiverse.

What flaw?

The strongest argument for a multiverse of which I'm aware is based upon the extreme unlikelihood of our present universe among all the others which might exist

If our part of the universe, given everything we know about it (including the fact of our own existence) were extremely unlikely and atypical in some multiverse model, that would rule out that model, not support it. That's how science works.

 

[Dave Rogers]

May I have written this same e-mail a trillion years ago????????????

No, that was me. Rule 4 violation reported. I should think Tegmark's multiple universes have some fascinating applications to intellectual property law.

Dave

 

[Molinaro]

So Tegmark's theory that whatever is possible must happen is therefore mathematically invalid. If you want to back off on that slightly and claim that whatever is possible may happen, you're on much sounder ground. But, of course, that statement is a truism -- it's essentially a restatement of the definition of the word "possible."

It seems to me that you are reading his theory differently than I see. You seem to be arguing based on an insistance on the existance of the infinitely many possible arrangements of the consituents of a given universe, rather than the existance of an infinite number of possible universes.

By possible universe I mean a region governed by a fixed set of mathematical relationships defining what we would call the laws of physics in that universe.

His theory seems to be talking about different sets of laws governing the constituents of a given universe. It says nothing about what arrangements of those constituents which must be present. The laws of physics in our universe don't preclude a planet made of marble rye. We could in fact build one over a very long period time if we chose to do it. However that it's possible is not the same as saying it must be.

 

[drkitten]

His theory seems to be talking about different sets of laws governing the constituents of a given universe. It says nothing about what arrangements of those constituents which must be present. The laws of physics in our universe don't preclude a planet made of marble rye. We could in fact build one over a very long period time if we chose to do it. However that it's possible is not the same as saying it must be.

Er, no. From his own page: (emphasis mine).

Level I: A generic prediction of inflation is an infinite ergodic universe, which contains Hubble volumes realizing all initial conditions - including an identical copy of you about 10^{10^29} meters away.

He's very much talking about the arrangements of the constitutents within the different Hubble volumes.

The real problem with his theory, as I pointed out, is the assumption of ergodivity. None of the well-regarded theories of the ultimate fate of the universe suggest that it is ergodic. From Wikipedia, "The ultimate fate of an open universe is either universal heat death, the "Big Freeze", or the "Big Rip," where the acceleration caused by dark energy eventually becomes so strong that it completely overwhelms the effects of the gravitational, electromagnetic and weak binding forces. [...] The ultimate fate of the universe is the same as an open universe."

 

[sol invictus]

The real problem with his theory, as I pointed out, is the assumption of ergodivity. None of the well-regarded theories of the ultimate fate of the universe suggest that it is ergodic.

That's not correct, but it's also irrelevant. Tegmark isn't using semi-infinite time to make his argument, he's using infinite space (although in fact the distinction is far less clear than you might think; what really matters is that there is an infinity in some direction).

So the question is whether the conditions for the universe at fixed time are "ergodic", meaning simply whether they range over all the possibilities he has in mind. As I said, in an infinite universe that underwent inflation it's very difficult to see how they could fail to.

From Wikipedia, "The ultimate fate of an open universe is either universal heat death, the "Big Freeze", or the "Big Rip," where the acceleration caused by dark energy eventually becomes so strong that it completely overwhelms the effects of the gravitational, electromagnetic and weak binding forces. [...] The ultimate fate of the universe is the same as an open universe."

That's flat-out wrong. Open universe can crunch, as can flat universes. Dark energy does not necessarily lead to any of the above (it can simply lead to an eternally inflating spacetime, or a quintessant one). But these are all red herrings, because none of those possibilities affect Tegmark's argument if the universe is spatially infinite.

 

[Norm Breyfogle]

Originally Posted by Norm Breyfogle View Post
How can you say that a Count Chocula universe is describable without contradiction? If there were no humans or tastebuds to taste it, in what consistent sense could it be said that it was Count Chocula at all?

- Norm Breyfogle

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By its chemical composition? I don't get your point.

- sol invictus

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My point is that a Count Chocula universe wouldn't have any humans in it to perceive any such Count Chocula chemicals. In other words, the only universes describable in a non-contradictory faction must have humans in it in order to be able to describe such universes at all. So, the Count Chocula universe can't exist.

 

[sol invictus]

My point is that a Count Chocula universe wouldn't have any humans in it to perceive any such Count Chocula chemicals.

It might or it might not. So what?

In other words, the only universes describable in a non-contradictory faction must have humans in it in order to be able to describe such universes at all.

What? Why? Who cares if there's anywhere nearby to describe it? And remember, we're not really talking about other universes, we're talking about one universe with different regions.

Not that it matters, since your argument makes no sense either way.

So, the Count Chocula universe can't exist.

Perhaps, but not by that "argument".

 

[plumjam]

I can see nothing contradictory in the existence of a Count Chocula. The fact that both vampires and chocolate are destroyed by direct exposure to daylight means chocolate is quite a suitable medium for vampiric forms; indeed almost poetically apt.
This only adds weight to the hypothesis, and is something I will be emailing Tegmark about forthwith.

 

[Norm Breyfogle]

sol invictus

I assumed the Count Chocula universe had no humans in it. But then, I can't see how a universe consisting only of Count Chocula AND humans could exist without contradiction, either. Would the humans breathe Count Chocula? Would they be COMPOSED OF Count Chocula? Then they wouldn't be human, would they? We are the result of the initial conditions of the Big Bang. A Count Chocula universe would clearly have developed from a radically different set of initial conditions, and humans wouldn't be in such a universe.

Be that as it may, my point is that merely describing a universe in a manner that one THINKS OR FEELS is non-contradictory doesn't guarantee that one's description is ACTUALLY non-contradictory or that one's description is exhaustive or accurate wrt the alternate universe in question. But the deepest contradiction of all in reference to such universes like the Count Chocula one is existential and philosophical: if a universe existed in which there was ONLY Count Chocula, would anyone know it? No, because by definition no one could perceive it in any way, even in principle, and so it would be meaningless to say it existed at all. Therefore, the actually existent non-contradictory universes must be ones much like ours in which humans exist.

If a tree falls in a forest and there's no one to witness it ... isn't it contradictory to claim that the tree fell at all? Without any proof at all?

The strength of multiple universe theories lie in their explanatory power wrt quantum paradoxes, but their weakness lies in the inevitable solipsism involved in attempting to conceive or perceive those other universe's existential realities. After all, we can only perceive that which we can perceive, and we can only conceive of that which we can conceive.

 

[sol invictus]

I assumed the Count Chocula universe had no humans in it. But then, I can't see how a universe consisting only of Count Chocula AND humans could exist without contradiction, either. Would the humans breathe Count Chocula?

You seem to be confused about the meaning of the term "contradiction". Your poor humans might die rather quickly under those circumstances, but there is no contradiction in them being there, just a massive and incredibly unlikely coincidence.

We are the result of the initial conditions of the Big Bang. A Count Chocula universe would clearly have developed from a radically different set of initial conditions, and humans wouldn't be in such a universe.

Wrong, according to Tegmark and according to a relatively straightforward application of physical reasoning and the standard concordance cosmological model (not that that proves it's correct). See my posts in this thread.

Be that as it may, my point is that merely describing a universe in a manner that one THINKS OR FEELS is non-contradictory doesn't guarantee that one's description is ACTUALLY non-contradictory or that one's description is exhaustive or accurate wrt the alternate universe in question.

Nor does feeling it is contradictory mean it actually is. To show it's contradictory you'll have to show it violates some principle of logic or some law of physics.

But the deepest contradiction of all in reference to such universes like the Count Chocula one is existential and philosophical: if a universe existed in which there was ONLY Count Chocula, would anyone know it?

Again:

1) We're not talking about separate universe. We're talking about different regions within one universe.

2) What difference does it make to the existence and reality of something if no one knows it? Answer: none.

No, because by definition no one could perceive it in any way, even in principle, and so it would be meaningless to say it existed at all. Therefore, the actually existent non-contradictory universes must be ones much like ours in which humans exist.

That doesn't follow either logically or according to the laws of physics. It's an unsupported assertion.

If a tree falls in a forest and there's no one to witness it ... isn't it contradictory to claim that the tree fell at all? Without any proof at all?

No, of course it isn't contradictory! Where are you getting this nonsense?

 

[Norm Breyfogle]

sol,

Please forgive my formatting; I don't know how to do the block quoting on this forum.

Originally Posted by Norm Breyfogle View Post
I assumed the Count Chocula universe had no humans in it. But then, I can't see how a universe consisting only of Count Chocula AND humans could exist without contradiction, either. Would the humans breathe Count Chocula?

You seem to be confused about the meaning of the term "contradiction". Your poor humans might die rather quickly under those circumstances, but there is no contradiction in them being there, just a massive and incredibly unlikely coincidence.

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Please indicate how a universe of Count Chocula could evolve humans within it. If anything is impossible due to both physical law and logic, something like that is so.

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Quote:
We are the result of the initial conditions of the Big Bang. A Count Chocula universe would clearly have developed from a radically different set of initial conditions, and humans wouldn't be in such a universe.

Wrong, according to Tegmark and according to a relatively straightforward application of physical reasoning and the standard concordance cosmological model (not that that proves it's correct). See my posts in this thread.

----------------

You're actually arguing for the physical and logical possibility of a Count Chocula universe which somehow has developed humans within it?

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Quote:
Be that as it may, my point is that merely describing a universe in a manner that one THINKS OR FEELS is non-contradictory doesn't guarantee that one's description is ACTUALLY non-contradictory or that one's description is exhaustive or accurate wrt the alternate universe in question.

Nor does feeling it is contradictory mean it actually is. To show it's contradictory you'll have to show it violates some principle of logic or some law of physics.

--------------------

Again, if anything is impossible due to inherent physical and logical contradictions, a Count Chocula universe must be extremely high up on a list of such items. If you can't see that contradictions are inherent to such a universe, then anything is indeed possible, and Tegmark is right! Is this what you're arguing?

---------------------

Quote:
But the deepest contradiction of all in reference to such universes like the Count Chocula one is existential and philosophical: if a universe existed in which there was ONLY Count Chocula, would anyone know it?

Again:

1) We're not talking about separate universe. We're talking about different regions within one universe.

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Universe; mulitiverse: semantics.

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2) What difference does it make to the existence and reality of something if no one knows it? Answer: none.

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Really? So you've solved the oldest problem in all of philosophy (the inevitable solipsism of consciousness)? Can you walk on water, too? Raise the dead?

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Quote:
No, because by definition no one could perceive it in any way, even in principle, and so it would be meaningless to say it existed at all. Therefore, the actually existent non-contradictory universes must be ones much like ours in which humans exist.

That doesn't follow either logically or according to the laws of physics. It's an unsupported assertion.

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Claiming (as, in essence, you've done, whether consciously or unconsciously) that one knows the ultimate relationship between consciousness and objective reality is an unsupported assertion.

-----------------

Quote:
If a tree falls in a forest and there's no one to witness it ... isn't it contradictory to claim that the tree fell at all? Without any proof at all?

No, of course it isn't contradictory! Where are you getting this nonsense?

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I'm "getting it" from the long history of philosophy and logic. Where are you getting the nonsense that you can logically or physically separate your consciousness from the objects of your consciousness?

 

[drkitten]

I'm "getting it" from the long history of philosophy and logic.

The only problem is that the long history of philosophy and logic inevitably rejects the solipsism of "if a tree falls in the forest when there's no one around, did it really fall?" in favor of philosophical realism.

And Max Tegmark's theories, in particular, assume philosophical realism. The multiverses exist and have properties regardless of whether or not there is an observer. From a physicist's perspective, of course, this makes sense, because physicists believe themselves capable of inferring properties of unobserved events by looking at observed secondary properties. We don't need to see the tree falling because we observe a decayed log lying there.

If your only response to Tegmark's theory is to postulate a theory that denies realism, then Tegmark is still wrong, because your counter-theory is philosophically incompatible with his.

Where are you getting the nonsense that you can logically or physically separate your consciousness from the objects of your consciousness?

From the 99.9999% of philosophers who accept realism.

 

[Norm Breyfogle]

"If your only response to Tegmark's theory is to postulate a theory that denies realism, then Tegmark is still wrong, because your counter-theory is philosophically incompatible with his."

- drkitten

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I haven't proposed a counter-theory. I'm merely pointing out certain questions re the issues in the OT.

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Quote:
Where are you getting the nonsense that you can logically or physically separate your consciousness from the objects of your consciousness?

- Norm Breyfogle

From the 99.9999% of philosophers who accept realism.

- drkitten

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A big majority of people in the ancient world believed in geocentrism.

Look, nothing I've said is mean to deny scientific realism. I'm merely pointing out that scientific realism can't deal effectively with the concepts of multiple universes because such concepts are so very far from being falsifiable at present and probably will remain so for a long time to come.

 

[drkitten]

I haven't proposed a counter-theory. I'm merely pointing out certain questions re the issues in the OT.

Yes, you have. You've proposed a rather silly counter-theory suggesting that a universe can't exist without humans in it to observe. You justify this by recourse to a non-mainstream philosophical position that is explicitly rejected by the vast majority of practicing philosphers as well as by all practicing physicists....

... and you wonder why the practicing physicists don't take your gaudy nonsense seriously?

Look, nothing I've said is mean to deny scientific realism.

Good. Then stop doing it.

I'm merely pointing out that scientific realism can't deal effectively with the concepts of multiple universes because such concepts are so very far from being falsifiable at present

Good. Then by your own admission, your entire set of objections to the Count Chocula Universe are scientifically invalid and philosophically inappropriate. More bluntly, they're irrelevant and in this context nonsensical.

Which is why they've (correctly) been dismissed as nonsense.

If you want to produce a scientific argument against Tegmark's theories, do not do so from a position that categorically rejects all of the scientific process.

 

[Norm Breyfogle]

drkitten

A universe that we can't EVEN IN PRINCIPLE conceive or perceive without contradiction is arguably nonexistent. This is philosophically legitimate, doesn't contradict scientific realism, and I was examining this point (which was in actuality raised by YOU in your "noncontradictory" comment) because it's relevant to the OT.

The rest of your response to me is inappropriately hostile and not worth my response.

 

[Roboramma]

A universe that we can't EVEN IN PRINCIPLE conceive or perceive without contradiction is arguably nonexistent.

Where do you get that idea? And in what way is a Count Chocula universe impossible to conceive in principle?
I can conceive it right now.