Wednesday, April 21, 2010

Causality and the Big Bang

Since Big Bang cosmology is the claim that matter, energy, space, and time all sprang into existence, it strikes many people as similar to the theistic doctrine of creation ex nihilo (and by "similar" I mean "identical"). So some philosophers and some cosmologists have tried to find ways of avoiding the theistic implications.

One of the most common is to claim that causality is a physical phenomenon; it describes what takes place within the universe. You can't apply it to the beginning of the physical universe. The idea here is that causality is a posteriori like the laws of physics or chemistry, not a priori like the laws of logic. As such, it only describes the conditions inside the universe and can't be applied to the beginning of the universe itself. This is the tack taken by some illustrious philosophers, such as Adolf Grünbaum and Quentin Smith

It's certainly true that causality is not a priori in the same way the laws of logic are. We simply can't imagine the law of non-contradiction failing to hold, but we can imagine causality failing to hold -- that is, we can imagine (form a mental picture of) something popping into existence without a cause. But it's incorrect to say that we discover causality the same way we discover the laws of physics, i.e. through observation. Causality is derived from our basic intuition that something does not come from nothing (ex nihilo nihil fit: out of nothing, nothing comes). To limit this intuition to physical processes would be a case of special pleading; there's no reason why it wouldn't apply to the beginning of the universe. Causality is not a physical principle, it's a metaphysical principle.

Perhaps one could suggest that once we have the principle of causality via intuition, we can then establish it via observation and continue to believe it based on the latter. But it's not clear to me how causality could be falsified, or what would count as observation of causality not holding. At best you could say that you didn't observe a cause of an effect, but everyone would infer that the effect does in fact have a cause and we just didn't observe it. It's not like you could set up a scientific experiment to observe the absence of causality, since if the conditions you set up are sufficient to bring about the effect, then obviously the former caused the latter. As such, I think William Lane Craig's argument that causality has never been falsified is an empty claim. There are plenty of times where we observe an effect without a cause, but no amount of such experiences will ever convince a sane person that the effects didn't have a cause, merely that the causes weren't observed.

Or, perhaps one could simply deny the intuition. There are problems with this though: for one thing, science presupposes causality. If causality goes out the window, science goes with it. This is not only absurd and unacceptable, it's a conclusion I doubt nontheists would be willing to accept, since they (mistakenly) think science is on their side. For another thing, while causality is not a priori in the same way that the laws of logic are, it is still a precondition of thought. If causality did not hold, then there would not be an appropriate connection between our beliefs and their objects, such that we could never know if any of them are true. So it's not merely scientific knowledge that would be endangered; if we deny causality, then the possibility of any knowledge becomes impossible. So it's not like this intuition is just some random assertion.

But doesn't quantum physics posit virtual particles coming into existence without causes? This is a misunderstanding. As Craig writes,

... virtual particles do not literally come into existence spontaneously out of nothing. Rather the energy locked up in a vacuum fluctuates spontaneously in such a way as to convert into evanescent particles that return almost immediately to the vacuum. ... The microstructure of the quantum vacuum is a sea of continually forming and dissolving particles which borrow energy from the vacuum for their brief existence. A quantum vacuum is thus far from nothing, and vacuum fluctuations do not constitute an exception to the principle that whatever begins to exist has a cause.

Another suggestion might be that Hume denied causality. But ignoring the fact that Hume was not inerrant, this is another misunderstanding. Hume argued that just because we've observed a particular cause producing a particular effect in the past, we cannot know that the cause will produce the same effect. In other words, he argued that we can't infer an effect from a cause. Those who deny causality applies to the creation of the universe are claiming that we can't infer a cause from an effect -- that just because we observe that an effect has taken place, we can't claim that it was caused. This is radically different from what Hume was claiming, and Hume explicitly repudiates such an idea as absurd.

A final claim might be to suggest that applying causality to the Big Bang is just as problematic for the traditional theistic doctrine of creation. The doctrine, after all, is called creation ex nihilo (out of nothing) and the intuition is that ex nihilo nihil fit (out of nothing, nothing comes). But again, this is a misunderstanding. Creation ex nihilo is the claim that the universe didn't have a material cause -- that it wasn't constructed out of some pre-existent "stuff". This is certainly a radical claim and we should recognize it as such. But it doesn't deny that the universe has an efficient cause -- some entity or agent that brings about the effect -- since the claim is that God is the efficient cause of the universe. Those who deny that causality would apply to the beginning of the universe, however, are claiming that the universe had neither a material cause nor an efficient cause. So I simply put it to you, which of these two explanations is more plausible: that the universe's beginning has an efficient cause but no material cause, or that it has neither?

Now it's all well and good to say that applying causality to the beginning of the universe creates some philosophical issues, but the alternative is that it just popped into existence without any cause whatsoever. That people who portray themselves as skeptics would be willing to accept this shows that their skepticism is absurdly selective. If this is the the only way to avoid believing in God then there's just no contest.

(cross-posted at Agent Intellect)


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12 comments:

desiderius said...

"Since Big Bang cosmology is the claim that matter, energy, space, and time all sprang into existence, it strikes many people as similar to the theistic doctrine of creation ex nihilo (and by "similar" I mean "identical")."

That shouldn't be all that surprising since the one who is responsible for the Big Bag Theory just happens to be Fr. Georges Lemaître, a Roman Catholic priest.

Matko said...

the Big Bag Theory

Well, I must say that certain analogies can be made between the universe and a bag.

TheOFloinn said...

Yes, but Fr. Lemaître specifically told the Pope, after the latter's too enthusiastic embrace of the theory, that the beginning of the space-time continuum should not be confused with creation.

http://www.youtube.com/watch?v=DS9fnee942E

Grad Student said...

An important point you've neglected to mention is that physical theory breaks down when the universe was younger than 10^-43 seconds, the so called Planck era, in the same way that physical theory breaks down at the singularity in a black hole. Thus, while scientists often say things like "time and space were created at the moment of the big bang," they're simply being lazy. In reality, all we can say is that the universe was hot and dense about 14 Gyr ago.

Thus, to posit that the big bang somehow resembles creation ex nihilio is to ignore the fact that the big bang theory, which is just a combination all the branchs of physics (thermodynamics, gravity, particle physics, etc.) simply fails earlier than 10^-43 s. Clearly what went on before 10^-43 s is a HUGE gap for cosmologists to fill, and if you're right about God and creation ex nihilo then cosmologists are tilting at windmills. As one of those "skeptics" you refer to, I prefer to withhold judgement on what exactly occurred so early in the universe.

Matt said...

A skeptic does not have to assert that the universe popped up out of nothing. All he has to do is say there are other explanations that are as good or better than Creation; therefore ending the argument at "God made it" is premature. Many atheists may agree with you that Creation is a better explanation than the universe just popped into existence but still hold that God didn't create the universe.

One competing idea I can think of (from reading A Brief History of Time, I'm no scientist so I could have misunderstood the argument or something new may have come along) is that understanding imaginary time allows us to see the universe as a single contained entity that has no beginning because imaginary time is unaffected by the singularity which would have started the big bang.

TheOFloinn said...

"it's a mystery [physical theory breaks down]"
"...imaginary time..."

Well, as long as it's not something weird and non-empirical.

Folks are still confusing "creation" with the beginning of space-time a long time ago. As Aquinas pointed out, an eternal universe would still be created. That is, "creation" is a metaphysical conclusion, not a physical hypothesis. It is not in competition with other physical theories (or even other made-up entities) as an explanation =how= a physical process operates.

Matt said...

Doesn't the option given to atheists in the blog entry "just popped into existence" imply beginning of space time? I don't see why, given the possibility of an endless universe (endless like a sphere, not endless as in time), an atheist cannot fall back on the uncaused argument.

I find "God caused it" to be more satisfying than an uncaused universe (afterall, from this we get purpose, morality, complete explanation of the origins of Christianity, promise of absolute truth and the ability to comprehend it) but it seems skeptics have better counter-arguments than this post implies.

TheOFloinn said...

No, because when they say they can imagine something poofing into existence from nothing, they usually imagine something like an empty table on which an apple suddenly appears, or a dark room in which something appears. But there is in those cases not nothing. There is a table, or a room.

Einstein taught us that "empty space" does not exist unless matter exists. (Time and space alike are consequences of the existence of matter.) Thus, any such act of imagination which begins with empty space is not beginning with nothing.

Besides, if we really did see an apple appear on a table top, our reaction would be not "WoW! Creation ex nihilo! Thanx God!" But rather, "Gee, I wonder where that came from?"

Lastly, though it shouldn't need saying, an act of imagination is not the same as an act of existence.

Matthew said...

One competing idea I can think of (from reading A Brief History of Time, I'm no scientist so I could have misunderstood the argument or something new may have come along) is that understanding imaginary time allows us to see the universe as a single contained entity that has no beginning because imaginary time is unaffected by the singularity which would have started the big bang.

We could also believe in spaghetti-time, a mathematical model too complex to comprehend because the equations that describe it are not like regular equations - they are literally like spaghetti.
Wow, that sounds like a really good argument. I mean, I have no clue what I just said, I am not physicist mind you, but it sounds like it appeals to the reasonable skeptic.

But if it doesn't, read Craig's "Hawking on God and Creation"

James Chastek said...

A few quibbles:

1.) You say we can imagine something popping into being with no cause. So assume something just pops into existence with no cause. Now imagine it popping into existence with a cause. What's the difference? The imagination conveys exactly the same data in either case: something is not there, then it is. Isn't it better to say that causality as such is not given to the imagination? This seems to be at the heart of Hume's critique. Aristotle and St. Thomas certainly would have agreed that causality (like substance and other such concepts) is not given to sensation, except per accidens. To see cause, substance, existence, act, power, person, meaning, etc. some act of the intellect must work within sense.

2.) The question you really need to ask is "what is caused"? Right now, you see that an effect is of a cause, but it seems the notion of an effect is taken as irreducibly primitive. I think it would be better to see "the caused" as ontologically composite, and to see ontological simplicity as primitive. Doing this, however, will limit to some extent the use you can make of physical theory.

3.) In physics, "cause" has to be verifiable in a metrical way, or at least linked to something that is, and as one commenter has pointed out, there are some rather immense metrical problems in speaking about the beginning of the universe in a physical sense.

James Chastek said...

Another notion more primitive than cause is "being before" or "being prior". A cause is a certain way of being before another. It's fruitful to compare this to the other ways of being "before", like in time and in position. A thing can come before in causality in spite of coming after in time; it can also be simultaneous; and a cause can sometimes have no position, etc.

Causes are not prior in time, but they are in existence (this forces us into some inquiry of existence). And this too is a hint about the sorts of things that need causes.

Ilíon said...

"As such, I think William Lane Craig's argument that causality has never been falsified is an empty claim. There are plenty of times where we observe an effect without a cause, but no amount of such experiences will ever convince a sane person that the effects didn't have a cause, merely that the causes weren't observed."

The second sentence contradicts the first.