Sean Carroll: Does the Universe Need God? [link]

post by Dreaded_Anomaly · 2011-03-23T19:31:17.926Z · LW · GW · Legacy · 22 comments

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22 comments

Does the Universe Need God? (essay by Sean Carroll)

In this essay, Sean Carroll:

See also his blog entry for more discussion of the essay.

Edit: added the bullet point about "meta-explanatory accounts."

22 comments

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comment by JGWeissman · 2011-03-23T22:15:11.088Z · LW(p) · GW(p)

*Discusses "meta-explanatory accounts":

Carroll argues that scientists are not obligated to provide a satisfying answer to "Why does something exist instead of nothing?", and shows some ways , but he does not disolve the question. The question, and related questions, remain interesting, and the answers if we can find it may still be useful.

Replies from: prase, Dreaded_Anomaly
comment by prase · 2011-03-24T08:32:46.531Z · LW(p) · GW(p)

To me this particular question was always absolutely uninteresting. What precisely dou you find interesting here?

If dissolving means explaining why some people find the question intriguing then there may be multiple dissolutions, each valid for some subset of people. E.g.

  • Belief that the broader its scope, the more important the question is. Questions about everything are broadest, thus most important and worth answering.
  • Instrumental value of this question (and particular answers to it) for justification of various arbitrary philosophies and religions.
  • Belief that any grammatically correct question has a sensible answer, perhaps a unique one. (Failing to recognise the limits of language.)
  • Belief that any fact should have a cause in some sense. (Failing to recognise the limits of intuitions.)
comment by Dreaded_Anomaly · 2011-03-23T22:44:51.995Z · LW(p) · GW(p)

No, he makes a stronger claim than that.

States of affairs only require an explanation if we have some contrary expectation, some reason to be surprised that they hold.
...
There is no reason, within anything we currently understand about the ultimate structure of reality, to think of the existence and persistence and regularity of the universe as things that require external explanation.

Replies from: JGWeissman, FAWS
comment by JGWeissman · 2011-03-23T23:03:55.388Z · LW(p) · GW(p)

No, he makes a stronger claim than that.

States of affairs only require an explanation if we have some contrary expectation, some reason to be surprised that they hold.

That claim is just an unsupported assertion.

Also, I take issue with the concept of a state of affairs requiring an explanation. Certainly this requirement is not a property of the state of affairs, it is rather a property of a mind that is considering the state of affairs. But what does it mean even then? That a mind with this requirement refuses to beleive the state of affairs without the explanation? That a mind that does believe the state affairs but lacks an explanination will compulsively search for an explanation? Well, fine, you can reject requiring an explanation under that sort of definition, and still be interested in an explanation.

Replies from: Dreaded_Anomaly
comment by Dreaded_Anomaly · 2011-03-23T23:20:23.935Z · LW(p) · GW(p)

We have no prior reason to expect that "nothing" would be a viable alternative to "something." Trying to explain "why existence" is pointless; existence is, inherently. Explaining how existence works is the useful and meaningful goal.

Replies from: lessdazed, David_Allen, samiam
comment by lessdazed · 2011-04-02T20:51:19.825Z · LW(p) · GW(p)

Are you saying something like the following?

There must be some true descriptions of a reality, i.e. actualized rules or meta-rules or meta-...rules, because just as "there are no applicable rules" is a meta-rule, "there are no rules or meta-rules or meta-meta-rules or meta-...rules" would be a meta-(meta-[meta-{meta-...}])rule.

So by counterfactually assuming no low-level rules while being indifferent to the number of (meta-[meta-{meta-...}])rules, we arrived at an infinity of (meta-[meta-{meta-...}])rules, one per level of meta after the lowest/first level: "There are no actualized rules, there is only one meta-rule, there is only one meta-meta-rule...there is only one (meta-[meta-{meta-...}])rule".

If there were any other lowest/first level rule, it would be possible to make a different meta-rule describing the lower rule and thereby form the base of what could only be a different infinite meta-tower than that described above as the result of not having low-level rules. In any case, that would be at least one base-level rule.

Therefore, the question "Why are there some true actualized (meta-[meta-{meta-...}])rules?" is ill-formed because it logically could not be otherwise.

Finally, if the question "why is there X rather than not X?" is ill-formed because the counterfactual of assuming (not X) led to a contradiction, then not (not X) i.e. X. So: not "why is it the case that there are at least some (meta-[meta-{meta-...}])rules rather than none?", rather, "there are at least some (meta-[meta-{meta-...}])rules."

Replies from: Dreaded_Anomaly
comment by Dreaded_Anomaly · 2011-04-02T21:00:15.805Z · LW(p) · GW(p)

Yes, that is what I'm saying. "Nothing" means no space, no time, no energy, no particles, no fields, no interactions... not even any "meta-rules," as you put it. Existence is fundamentally the context of everything, regardless of at how many levels we can describe it, or how many forms the rules could or do take. When we discuss phenomena within the context, it can make sense to say "why is there X rather than not X (or Y, or Z...)", but it doesn't make sense to discuss the context itself in that way.

Replies from: lessdazed
comment by lessdazed · 2011-04-02T23:49:54.307Z · LW(p) · GW(p)

it doesn't make sense to discuss the context itself in that way.

As I think of it, it does make sense to talk about the wider context of the rules, which are the meta-rules, but it does not make sense to demand a context that cannot itself be described within a wider context.

(If a (meta-[meta-{meta-...}])ruleset had a horizontal slice of the meta-tower identical to the other immediately higher and lower slices, then it would provide its own context. Somehow the rules and meta-rules would have to be identical, but it would still have a context, it just wouldn't be a different context. I'm not sure this is possible, but that "possible" world isn't ours anyway. If it were, the rules would be the meta-rules too, and we wouldn't have to look deeper.

I strongly doubt the tower can repeat, e.g. with rules identical to meta-meta-rules, unless they are also equal to the meta-rules and every other level.

The "tower" with rules on the bottom, meta-rules above that, etc. is either repeating or non-repeating, but I don't see how it could have a limited number of floors.)

Regardless, if the rules/first floor is empty (i.e. there are no rules by which anything exists) then the meta-rules/second floor has an occupant (i.e. "there are no rules by which anything exists") so the meta-tower isn't empty.

comment by David_Allen · 2011-03-24T17:25:27.074Z · LW(p) · GW(p)

We have no prior reason to expect that "nothing" would be a viable alternative to "something."

I absolutely agree with this. To establish that "non-existence" is exclusively opposed to "existence" requires a careful analysis of the nature of existence.

Can anybody point to work along these lines? I am actively researching the topic.

Trying to explain "why existence" is pointless; existence is, inherently.

I'm not sure how you mean this. By "why existence", do you mean something like the "purpose of existence"?

Explaining how existence works is the useful and meaningful goal.

I agree. I think that this topic ties directly to epistemology; explaining the nature of existence will help to explain the nature of knowledge.

Replies from: Dreaded_Anomaly
comment by Dreaded_Anomaly · 2011-03-24T23:07:46.036Z · LW(p) · GW(p)

I'm not sure how you mean this. By "why existence", do you mean something like the "purpose of existence"?

I mean in the sense "why does existence exist?". It's really an inappropriate question, despite our ability to phrase it in what seems like a grammatically/linguistically correct way.

Replies from: David_Allen
comment by David_Allen · 2011-03-25T01:48:48.615Z · LW(p) · GW(p)

I mean in the sense "why does existence exist?".

Then I agree that this question is probably poorly formed. Certainly it isn't obvious to me that it is a meaningful or useful question.

I'm not sure why we have been down-voted for these comments. I suspect that it is because questioning existence in this way appears to challenge the "objective existence" aspects of scientific realism. (Down-voters please comment if I'm wrong.)

Replies from: Dreaded_Anomaly
comment by Dreaded_Anomaly · 2011-03-25T01:53:56.652Z · LW(p) · GW(p)

I'm not sure why we have been down-voted for these comments. I suspect that it is because questioning existence in this way appears to challenge the "objective existence" aspects of scientific realism. (Down-voters please comment if I'm wrong.)

I have had a fair amount of downvoting on this topic, with very little explanation. It's somewhat frustrating.

Replies from: David_Allen
comment by David_Allen · 2011-03-25T02:18:59.212Z · LW(p) · GW(p)

Same here.

comment by samiam · 2011-04-04T03:44:04.426Z · LW(p) · GW(p)

sigh this is an unfortunate reply

First, the point made about no time existing prior to the Big Bang applies just as readily to the Standard Model as it does to Hawking's newer model (which fudges math to create imaginary time and a "no boundary" version of the beginning). This new version accomplished nothing (no pun intended), because under any model it is nonsense to ask "What existed before time?" (because "before" is a temporal term, obviously). However, the question of WHY is there a universe at all? (i.e. what is the REASON?) is a perfectly fair question that should not be avoided (and is not temporally-based).

You said, "We have no prior reason to expect that 'nothing' would be a viable alternative to 'something.'" Of course we do! Our experience ONE-HUNDRED PERCENT of the time contradicts this statement.

You said, "Trying to explain 'why existence' is pointless; existence is, inherently." You're committing the taxicab fallacy. You can't just dismiss the causal principle at the point you're "ready to get out." If anything in your daily life happened out of the ordinary (like your car changed colors or someone threw a rock through your window), you would look for a sufficient REASON (because there IS one).

Finally, you said, "Explaining how existence works is the useful and meaningful goal." Um, this is useful and meaningful (I agree), but we are only able to accomplish this using a little thing called the "Law of Causality." So you're willing to use the causal principle for EVERYTHING all the way back to the beginning, but then you choose to stick your head in the sand?

Once again...unfortunate.

Replies from: Dreaded_Anomaly
comment by Dreaded_Anomaly · 2011-04-04T04:42:23.391Z · LW(p) · GW(p)

Did you actually read the essay?

In Aristotle's Metaphysics, he suggested the need for an "unmoved mover" to explain the motion of ordinary objects. That makes sense in the context of Aristotle's physics, which was fundamentally teleological: objects tended toward their natural place, which is where they wanted to stay. How, then, to account for all the motion we find everywhere around us? But subsequent developments in physics – conservation of momentum, Newton's laws of motion – changed the context in which such a question might be asked. Now we know that objects that are moving freely continue to move along a uniform trajectory, without anything moving them. Why? Because that's what objects do. It's often convenient, in the context of everyday life, for us to refer to this or that event as having some particular cause. But this is just shorthand for what's really going on, namely: things are obeying the laws of physics.

Likewise for the universe. There is no reason, within anything we currently understand about the ultimate structure of reality, to think of the existence and persistence and regularity of the universe as things that require external explanation. Indeed, for most scientists, adding on another layer of metaphysical structure in order to purportedly explain these nomological facts is an unnecessary complication.

However fundamental you think the "causal principle" may be, modern physics is not done that way.

You're making statements about events or phenomena that happen within the universe, and then taking a gigantic, unfounded leap to apply the same principles to the universe itself. How could we possibly have a prior reason to expect the absence of all existence? Not the existence of some specific thing, but existence, in the broadest sense.

comment by FAWS · 2011-03-23T23:38:58.207Z · LW(p) · GW(p)

States of affairs only require an explanation if we have some contrary expectation, some reason to be surprised that they hold.

That's certainly a requirement for that state of affairs being evidence for anything, but it's not so clear for requiring an explanation, mostly because there seems to be no rigorous sense of what "requiring an explanation" means in the first place.

Replies from: komponisto
comment by komponisto · 2011-03-24T21:00:38.502Z · LW(p) · GW(p)

there seems to be no rigorous sense of what "requiring an explanation" means in the first place.

"Requiring an explanation" means "low probability". An "explanation" is a datum such that conditioning on it makes the probability high.

You can think of probability as an "inverse surprise score" that you try to keep as high as possible. (And of course, there's no cheating.)

Replies from: wnoise, FAWS
comment by wnoise · 2011-03-24T22:44:56.346Z · LW(p) · GW(p)

negative surprise log score?

comment by FAWS · 2011-03-24T21:33:36.419Z · LW(p) · GW(p)

So "requiring an explanation" means "strong evidence the hypothesis space has not yet been searched for"? That seems plausible. Is this your on the spot suggestion or has it been discussed before?

comment by Will_Newsome · 2011-03-24T03:31:41.735Z · LW(p) · GW(p)

On cosmology, I found Theory of Nothing quite interesting even if a whole bunch of it has been rightfully replaced by SL5 decision theory / cosmology concepts. It basically summarizes the kind of cosmology that was going on on the Everything mailing list before it got quiet. It's probably the best place to go if you don't have the luxury of hanging out with certain people in the Visiting Fellows program at SIAI for a year. The idea that an infinite ensemble, like the Library of Babel, has no information content (as seen from the 'outside), dissolved a few confusions for me (though of course many are left) and gave me something of a momentary experience of sunyata. I don't contemplate that thought much anymore for fear that I will 'use up' the novelty of sunyata.

comment by Nisan · 2011-04-04T12:15:56.459Z · LW(p) · GW(p)

Tsk-tsk. He rejects the hypothesis of a single universe because he fails to consider the anthropic principle.

comment by Saladin · 2012-02-07T19:27:50.001Z · LW(p) · GW(p)

As hard as I try I cannot fathom the: "If it's untestable, anything is possible - if anything is possible, nothing is possible - nothing is the simplest and therefore best explanation" argument.

Everything requires a reason (the Existence of a reason or cause - if its comprehensible and testable is a separate question) The fundamental question always go back to "why and how Existence at all". Of course we cannot make direct measurements regarding the origin of Existence - but we can certanly base our hypothesis and theories on our acumulated knowledge and daily, testable physics. The corect logic would therefore be to extend all the known and proven constants into the unknown (through symetries, conservation of energy, ..) - not to allow there every single possibility, specially illogical ones,. Or to put it simply: Only when You eliminate the logical, can You turn to the illogical.

Nothing conclusive from our past and currenty physical knowledge proves, that Creatio Ex Nihilo is an actual phenomenon or even that it is physically/logically possible. Most importantly - there is not one single complete idea (that I know of) that explains the mechanism, of how absolute Nothingness (Non-Existence) can spring forth anything else but further "Non-Existence". I don't need to stress out that there is even less talk about why this Non-Existence would produce or could even allow for just one single universe. If anything - if Non-Existence could produce our universe it could (and must of have) produced many - if not all physicaly/logical universes - if not even more, illogical ones. Seems to me, that if You want to talk about true Creatio ex hinilo - You must support the notion of a max. large multiverse: An Ultimate Ensemble (which is the totally opposite view most people wan't to prefer Creatio Ex Nihilo for - Occam can be tricky sometimes).

Sure, there are theories that promote the idea of the Big Bang "from nothing", but there is always "something", that causes the Big Bang and that "something" never gets explained, which only pushes the question to the origin of "that" cause. And it usually hangs as being a sort of First Cause, a "Something" in existence, which is by far a better option than Creatio Ex Nihilio. You can include causality, entropy and similar notions to any kind of "Something" - but never to Nihilo.

True Non-Existence, event though a concept we never experience in reality, is a beautifull thing, because it has only one, clear and strict meaning. Total absence of anything and all (spacetime included). If its not that - it's "something". Of course, if it''s not Creatio Ex Nihilo, then we have to assume a past eternity of some kind (be it Primus Movens or a cyclic/paralel model). Sure - past eternity brings out problems - but not as many as a single or multiple Creatio Ex Nihilo. But Past eternity is based on factual knowledge and observation - its an extension of what we know into the unknown, rather making up new types of logics and physics.

the best way I found is to use modal logic for such issues: Everything can (quite easily and reasonable) be put into 2 categories: Actually possible and potentially possible. Actually possible are known and proven possibilities (assuming hard determinism doesn't hold, but thats a separate question), I could go left or right - a car could pass my house or it could not, etc. Potentially possible are possibilities, that "might be possible". It might be possible to go faster than light, to alter all the physical constants we know, etc. But it's not proven to be possible (and of course, the possibility never happened that we know of).

We can quite easily and rationaly posit, that there are no physical proofs and explanations for Creatio Ex Nihilo while it the same time we know that conservation of energy, causality, etc.... are proven and real constants (and that in some physical models we can show how the Past Eternal models are consistent, logical and give observable predictions).

Creatio ex Nihilo with its non-existing logic and missing proof is surely a "possibily possible" scenario, while Past Eternity is (if combined with specific physical models) an "actually possible" scenario. The first one is clearly less possible and less logical and we must conclude, that the second model is more probable.

And I come back again: Why go against Occam and favor Creatio Ex Nihilo, when we have simpler and logical alternatives? It baffles me. I can only attribute that to personal biases and/or extremley narrowminded "horse blinders" approach, that simply cannot give a complete and objective picture. Yes - accepting Past eternity means opening a Pandoras box worth of possibilities - but keeping Your eyes shut is not good, objective science.

As long as we have logical options (however complex) they will always be more probable then illogical ones. Occam favours "real" options above "potential" options.

Does the Universe need a God? Maybe not - but God definetly needs a universe and a past eternal one guarantees Gods existence if God is "actually possible" (Posthuman- or otherwise).