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 Quodlibeta)

7 comments:

Nick said...

Another option is Kant's, and it is undeniably elegant. The confusion regarding the beginning of the universe arises when empirical reasoning tries to stretch beyond its boundaries. The paradox of an uncaused "first cause" arises only because we are trying to apply characteristics of our experience (namely, time, things occurring in succession) to things-in-themselves.

For Kant, the problem is not one to be solved, but one which indicates the limits of our powers of reasoning. Finite, limited creatures cannot understand the infinite and unconditioned.

Matko said...

You don't have to deny the law of causation, but you can argue that there are some conditions that must be fulfilled if A wants to cause B. Hume mentioned spatial contiguity and temporal succession. There are counterarguments to the first one (a horn alarms workers that the lunch break is over), but any causation we have ever observed happened in time. The problems I see is with nontemporal causation. How can A cause B if there is no time and space?

Timothy Mills said...

Can you point me to a source which claims "that matter, energy, space, and time all sprang into existence" in the Big Bang?

I've heard it suggested (not asserted, just speculated) that time and space came into existence then. But ... well, for what it's worth, here's the Wikipedia description of the state of things before the bang:

"Extrapolation of the expansion of the Universe backwards in time using general relativity yields an infinite density and temperature at a finite time in the past."

Which seems to imply a belief that matter and energy existed at the earliest point at which the author speculates about.

I don't find any suggestion of a belief that there was a "nihilo" state out of which everything sprang.

I agree with you that those who make positive claims about what preceded the Planck epoch (as the first moments of the Big Bang are called) are setting aside skepticism, and are vulnerable to the objections you raise. However, I don't think that Big Bang cosmology as a scientific theory suffers from the same problems.

Matko said...

Nick said:

Another option is Kant's, and it is undeniably elegant. The confusion regarding the beginning of the universe arises when empirical reasoning tries to stretch beyond its boundaries. The paradox of an uncaused "first cause" arises only because we are trying to apply characteristics of our experience (namely, time, things occurring in succession) to things-in-themselves.

For Kant, the problem is not one to be solved, but one which indicates the limits of our powers of reasoning. Finite, limited creatures cannot understand the infinite and unconditioned.


If you're alluding to Kant's antithesis of his first antinomy, Craig dealt with it when he formulated the Kalām cosmological argument in the late seventies.

Jim S. said...

Nick: About the same time you wrote your comment, I was reading the first chapter of Plantinga's Warranted Christian Belief which goes into some detail about Kant and his claim that we apply our categories beyond their scope in such things. I agree with you that Kant's option is elegant, but don't think it holds water.

Matko: per your first comment, I would say that the fact that we've only experienced causality in time is just as easily explained by the fact that we are temporal beings. This would also explain why we find the idea of nontemporal (or atemporal) causality unusual, although not incoherent. Temporality is an accidental aspect of causality in our experience, not an essential aspect of it.

Tim: I think the original essay was "The Singularities of Gravitational Collapse and Cosmology" published around 1970 by Stephen Hawking and Roger Penrose. Einstein's general relativity equations dictated that all the matter and energy in the universe are expanding outward from a singularity (a point of zero volume); Hawking and Penrose extended general relativity to include the dimensions of space and time. The space-time theory of general relativity has developed its own literature. As far as I know, it's universally accepted by physicists, astronomers, and cosmologists.

Timothy Mills said...

Hmm... I remain skeptical, but have no good basis for dissent, so I will concede the point for now.

However, I have another objection. (I know, you were hoping I'd say that, weren't you?)

You say that "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." I disagree.

The Wikipedia article on special pleading suggests that "In philosophy, it is assumed that wherever a distinction is claimed, a relevant basis for the distinction should exist and be substantiated. Special pleading is a subversion of this assumption." Let me argue for a relevant basis for this distinction.

Our intuitions about causality are derived exclusively from spatio-temporal events. There is no obvious reason why these intuitions should extend to non-spatio-temporal phenomena, such as the border between nihilo and the Big Bang.

Consider also that, through most of human history, the intuition that objects in motion tend to come to rest was quite justified. It works anywhere on Earth that people happen to be. But it fails when you reach the effectively frictionless environment beyond our atmosphere.

History is littered with the broken shells of egocentric intuitions, shattered by contact with the new and alien. So until you can demonstrate to me that this causality intuition should apply beyond the spatio-temporal realm in which it has been exclusively formed and trained, I will reserve judgement.

Timothy Mills said...

Looking back on my tendency to polarize against your position, Jim, I think it is worth mentioning that I find first-cause arguments to be one of the two most plausible lines of arguments in support of the possible existence of a supernatural creator being. Slightly ahead of them in my mind are fine-tuning arguments.

Together, they give me pause. They do not persuade me, and they certainly do not point to a personal being of the sort that most religions posit, but they do encourage me to avoid outright rejection of the god-hypothesis as untenable.

I remain an atheist, as I still lack positive god-belief, but I am an agnostic atheist.