Thursday, July 10, 2008

The Ambiguous Faith of Paul Davies

I'm a bit late to the party in replying to this guest editorial for the New York Times by physicist and science writer Paul Davies (November 2007). Davies is a writer whose books I've always enjoyed, so this muddled attempt at philosophy of science came as a bit of a surprise. Davies' piece, Taking Science on Faith, uses the term "faith" in a completely ambiguous fashion in order to equate the underlying assumption that scientists have in an orderly universe with the faith that religious people have in the existence of a god. Here are a few paragraphs (you should read the whole thing however) which outline the ambiguity in Davies' use of the word "faith". I've linked terms that require some background knowledge:
The problem with this neat separation into “non-overlapping magisteria,” as Stephen Jay Gould described science and religion, is that science has its own faith-based belief system. All science proceeds on the assumption that nature is ordered in a rational and intelligible way.

When I was a student, the laws of physics were regarded as completely off limits... The laws were treated as “given” — imprinted on the universe like a maker’s mark at the moment of cosmic birth — and fixed forevermore. Therefore, to be a scientist, you had to have faith that the universe is governed by dependable, immutable, absolute, universal, mathematical laws of an unspecified origin...

The multiverse theory is increasingly popular, but it doesn’t so much explain the laws of physics as dodge the whole issue. There has to be a physical mechanism to make all those universes and bestow bylaws on them. This process will require its own laws, or meta-laws. Where do they come from? The problem has simply been shifted up a level from the laws of the universe to the meta-laws of the multiverse.

Clearly, then, both religion and science are founded on faith — namely, on belief in the existence of something outside the universe, like an unexplained God or an unexplained set of physical laws, maybe even a huge ensemble of unseen universes, too. For that reason, both monotheistic religion and orthodox science fail to provide a complete account of physical existence.

...the laws should have an explanation from within the universe and not involve appealing to an external agency. The specifics of that explanation are a matter for future research. But until science comes up with a testable theory of the laws of the universe, its claim to be free of faith is manifestly bogus.

I agree with Davies that the laws of the universe (be it our one universe or the fact that our universe is merely one of the universes in a multiverse) need to be explained from within, without invoking an outside agent (god or otherwise). However, his use of the word "faith" is an example of Ambiguity. I would argue that using the word "faith" in a scientific context is inappropriate. However, even if we do say scientists have faith in the intelligibility of the universe and faith that the universe is governed by laws of physics, this is not the same faith as used in a religious context. The wikipedia entry on faith certainly makes this clear (and who doesn't have faith in the legitimacy in citing wikipedia!). I'd say the simplest, most common usage of faith is something along the lines of this:
Belief that does not rest on logical proof or material evidence.
The encapsulates religious faith (this is not to say religious faith is irrational) but is clearly not "scientific faith". Scientific faith (again, I emphasise this is not a term I think ought to be applied, but I'm granting Davies this in order to point out the ambiguity) is based on testable evidence, logical deduction, induction, and an underlying and often unstated premise of Occam's razor. I am now going to plagiarise bits and pieces from an article I wrote, originally published in Philosophy Now.

We can't logically prove our faith in the laws of physics. However, we can justify it rationally. And this ratiocination ends up doing away with the faith argument as a basis of scientific belief. It's not necessary to have faith that gravity acts the same elsewhere in the universe as it does here. The solution lies in the difference between logical and rational. Although we cannot establish the logical truth of this claim, it is possible to establish a rational explanation for why we can assume it. ("Assume" is actually the correct term for science, rather than "faith". Scientists justifiably, as I'll now show, take particular assumptions for granted.)

A clear distinction needs to be made between what is meant by logical and rational. These two words are often used in the same context, but there is a subtle yet extremely important difference. Logical reasoning, in its strictest sense, is valid because of the tautological nature of a statement. If you are introduced to a bachelor, it follows that he is an unmarried man. This is a logical deduction from the premise. Whereas someone suggesting that red is not a colour, is logically false, because by definition red is a colour. A rational explanation is to justify a position by a reasoned and plausible argument. It does not have to contain a logical truth; it just has to be a reasoned statement that is not logically false.

The philosopher Daniel Dennett suggested one way of looking at the likelihood of something occurring, or just existing, is by classifying it into a grade of possibility. First is logical possibility, which as before is simply that of a statement not being contradictory to itself. It is logically possible for me to breathe water. Then comes physical possibility. While it is logically possible for me to breathe water, it is not physically possible for me to do this (and live). Following this line of reasoning, let's look at statements about the nature of our universe that Davies says scientists have faith in:
1. It is logically possible that we exist in a universe of a uniform nature, in terms of it having universal laws that explain it.
2. It is also physically possible that we exist in a universe of a uniform nature, in terms of it having universal laws that explain it.
What type of physical phenomena and experiences would we expect to see and have if these were more than mere possibilities, but actual truths? Well for one, if we actually manage to stumble across a universal law through theoretical work and/or experimentation, we would also be able to see the workings of this law wherever we look in the universe. Guess what? This is what happens!

Of course, we could imagine a great many different states the universe might exist in, which for the moment, are consistent with this evidence. One example: it appears that gravity (say) operates the same everywhere in the universe, but this is actually an illusion due to the different behaviour of electromagnetic radiation in other parts of the universe.

There could be even more possibilities than this, and they all could explain the observations equally. However, one explanation requires the least steps. The one that assumes the laws of the universe are ubiquitous.

A universe that can be explained in terms of universal laws is the least complex state of affairs we can envision. Any other explanation for our universe cannot be anything but more complicated. If half of the universe can be explained by one set of laws, and the other half explained by another set of different laws; then it is a more complex universe than one governed by a single set of laws. Thus if we accept Occam's razor, we can dismiss any unnecessarily complex explanation for the workings of the universe (until such time we have positive evidence in its favour), simply because it is unnecessarily complicated.

This is not a logical argument (as it was previously defined) as we have to accept Occam's razor a priori; but it is a rational one. We can see that the premise of a universe with universal laws is the simplest explanation for the phenomena we experience in our observable region of space. At this stage we have no rational reason to favour any other premise over this one. But we do have a rational reason to give it favour. The acceptance of Occam's razor allows the rational belief of a uniform universe governed by universal laws. There is no "faith" required here.

I'll re-cite Davies' last paragraph to make a final point:

...the laws should have an explanation from within the universe and not involve appealing to an external agency. The specifics of that explanation are a matter for future research. But until science comes up with a testable theory of the laws of the universe, its claim to be free of faith is manifestly bogus.

Davies mistakes the fact that we don't yet have a testable theory for the "ultimate" laws of the universe for faith there are ultimate laws. This is a "bogus" point. We don't need faith to claim there are ultimate laws to the universe when we have no evidence to the contrary (i.e., no good reason to not believe it) and when we have evidence consistent with this claim (evidence to believe it). And, as Davies does say, we're working on it...