Friday, June 18, 2010

What we know and what we don't know about "laws of nature"

Sean Carroll, a physics professor and blogger who hangs intellectually with Jerry Coyne and P. Z. Myers, is calling it quits over at his blog, and he writes one last post, which is apparently meant to summarize what his blog has been about. It exemplifies many of the things that are wrong with the modern scientistic mindset.

One of the characteristics of this mindset is the belief that certain things are known which are really not known. These are the "well, of course everyone knows" things that we are all just supposed to assume, like good little secularists.

Here is Carroll explaining one of the things that, of course, everyone knows:
Over the last four hundred or so years, human beings have achieved something truly amazing: we understand the basic rules governing the operation of the world around us. Everything we see in our everyday lives is simply a combination of three particles — protons, neutrons, and electrons — interacting through three forces — gravity, electromagnetism, and the strong nuclear force. That is it; there are no other forms of matter needed to describe what we see, and no other forces that affect how they interact in any noticeable way. And we know what those interactions are, and how they work. Of course there are plenty of things we don’t know — there are additional elementary particles, dark matter and dark energy, mysteries of quantum gravity, and so on. But none of those is relevant to our everyday lives (unless you happen to be a professional physicist). As far as our immediate world is concerned, we know what the rules are. A staggeringly impressive accomplishment, that somehow remains uncommunicated to the overwhelming majority of educated human beings.
Carroll thinks he knows "what the rules are." And by "rules," we assume (given what he says later in the post) he is referring to what are popularly known as the "Laws of Nature." But there is a serious question whether he actually does. In fact, it's a live question whether anyone does.

Carroll seems to be confusing the idea of knowing that something is with the idea of knowing what something is. It would indeed be a staggeringly impressive accomplishment if he did know what they were, but, in fact, he doesn't. He can show us the effects of these Laws of Nature, but he cannot tell us what they are. Are they prescriptive entities of some kind that issue commands? If so, then what exactly is the ontological status of these "laws"? And how is his view effectively different from a belief in some kind of god?

Or are they simply a collection of descriptive observations of the past behavior of certain things under certain circumstances. If so, then can anything worthy of the name "law" really be said to exist at all? And what logical force can they possibly exercise (as David Hume pointed out) for predicting the future?

People like Carroll want to be able to rid themselves of any metaphysical baggage, but as soon as they try to explain their own position, they are faced with either engaging in metaphysics or repudiating the rational foundations of their own position.

3 comments:

KyCobb said...

Martin,

"Or are they simply a collection of descriptive observations of the past behavior of certain things under certain circumstances. If so, then can anything worthy of the name "law" really be said to exist at all? And what logical force can they possibly exercise (as David Hume pointed out) for predicting the future?"

The behavior has been the same throughout the observable universe for nearly 14 billion years. However science doesn't claim to possess absolute truth, and its ok if scientists don't know absolutely everything yet-that gives them something to study in the future. Scientists make predictions based on the regularities they observe, and as we learn more, theories are modified and new theories developed to more accurately model the universe. Should the three forces suddenly change, we won't have to worry about our inability to use them to make predictions, because we'll all be dead.

Martin Cothran said...

KyCobb,

I would love to hear how you know what has gone on in the observable universe (is that distinct from the unobservable universe?) for 14 billion years, not that that has the least bearing on the point of this post, which is that no one knows the nature of the Laws of Nature.

If you know what they are, I would love to hear that too. That would have something to do with the post.

KyCobb said...

Martin,

"I would love to hear how you know what has gone on in the observable universe (is that distinct from the unobservable universe?) for 14 billion years"

I would think its kind of obvious from the fact that the observable universe is observable. Because light has a speed limit, it takes time for it to reach the earth from where it originated. We don't see the stars and galaxies as they are now, but as they were when the light was emitted-in the case of the most distant objects we can see, billions of years ago. Thus scientists are able to observe that matter then was behaving the same way as matter does now.*

This is a stunning accomplishment, and I don't see the implication you see that Sean Carroll was implying anything more than that.

*Some parts of the universe may be so far away that its light cannot reach us, and in its earliest stages there was no light, so we cannot observe those portions of the universe.