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Tuesday, September 2, 2008

Causes, Explanations, and Goals

In a reply to my post, Irrationality and Religious Belief, a friend of mine asked the following question:

What's the difference between asking, "Why are the laws of chemistry as they are, such that atoms react to form molecules, and so forth" and, "Why are the laws of physics and everything in the Universe the way that they are? Why does matter behave as it does? Is there an ordered end or 'goal' toward which it, and ultimately the universe, is progressing?"

There are four distinct questions there, and I want to explain how I think they are unique.

First, consider how many different ways we can answer "why" questions. Aristotle famously identified four ways. First, the material cause, which tells us the materials which comprise a phenomenon. Second, the formal cause, which tells us the organizational principles which define a phenomenon. Third, the efficient cause, which tells us the entities which are historically responsible for a phenomenon's occurence. Fourth, the final cause, which tells us the purpose or goal which a phenomenon is intended to produce.

We could discuss whether or how we might improve upon Aristotle's distinctions here, but I don't think that will make a difference to what I'm about to say. I will only point out that we often don't distinguish between the first and second causes, because form and matter are often indistinguishable.

Consider the question, "why are there 24 hours in a day?"

We might answer by saying that 24 hours is approximately the time it takes for the earth to rotate around its axis as it revolves around its light source, the sun. This tells us the material causes (the earth and sun) and the formal cause (the earth's revolution and rotation). We can answer the question in more depth, looking for the efficient cause, by talking about why it is that the earth's rotation has a 24-hour period. Or, if we have reason to believe that the period of the earth's rotation was intentional, we could ask about its final cause, asking, for example, why did God create the earth so that we experience 24-hour days?

We have no reason to look for a final cause of the earth's rotation, of course. There is no evidence that the earth was created by a conscious being. So we consider a complete answer one that identifies the material, formal and efficient causes.

Now let's turn to the questions which began this post.

The first question is, "why are the laws of chemistry as they are?"

In terms of material causes, we can say that the laws of chemistry are the way they are because atoms are composed of subatomic particles which have their own regularities. We can thus explain chemistry in terms of physics. This tells us the material and formal causes. We can also look for an efficient cause by exploring the history of the universe and determining what specific factors, if any, contributed to the laws of chemistry. Since there is no evidence for any final cause, there is no reason to look for one.

The second question is, "Why are the laws of physics and everything in the Universe the way that they are?"

Scientists don't have a definite answer for this question, so far as I know. However, the question can be approached scientifically. It is possibile that some laws of nature are unchanging, and are the way they are because of some unchanging property of the universe itself. In that case, there is no efficient cause at work here. We can only study the material and formal properties in which nature's laws are manifest.

However, cosmologists have considered how changes in the universe could affect the universe's constants, like the speed of light, which we were all taught was always the same. It is quite possible that, as the universe evolves, its constants change. The speed of light might have been faster when the universe was a lot hotter. The laws of nature might not be fixed. Thus, efficient causes for the laws of nature may be scientifically identified one day.

Again, without evidence for a final cause, there is no reason to look for one.

There are also some laws which apply to any possible world in which certain conditions are met. When the universe meets those conditions, the law is inevitable. Darwin's theory of Natural Selection is one such law. The law of supply and demand could be considered another. We can analyze such laws in terms of their material, formal, and efficient causes.

The next question: "Why does matter behave as it does?"

This question can be answered by referring to the answers to the previous two questions.

Finally: "Is there an ordered end or 'goal' toward which it, and ultimately the universe, is progressing?"

This question contains two separate questions. The first, is there some final state towards which the universe is progressing? The second, is there some goal of the universe?

Scientists have theorized about possible "final states" of the universe, based on the facts that the universe is expanding and that entropy increases over time in any closed system. If the universe continues to expand without contracting, they say, there will be a "heat death," which is equivalent to maximum entropy. If the universe contracts, however, then there could be some kind of expansion/contraction cycle, which may never have a final state. These questions are all of the material/formal/efficient cause variety. They don't indicate any final cause.

As for there being a goal of the universe, however, this implies a final cause. It implies that the universe has some purpose, and that it is or was intended to achieve something in particular.

Final causes make sense when we are talking about beings who behave intentionally. The universe does not appear to behave intentionally. We have no reason to think that there is any intention behind, for example, galaxies, earthquakes, and the formation of planets. So we have no basis for talking about these phenomena in terms of final causes.

Of course, one might say, "ah, but there is no reason why we cannot talk about such things in terms of final causes!"

In general, that is true. If you want to talk about earthquakes as being the product of some conscious being, you can. I think it is irrational to put too much stock in the idea, but it is not inconceivable that such events could be caused by conscious beings. (In fact, one day we may very well have enough control over the planet to produce controlled earthquakes ourselves. Why we would want to is another question entirely.)

But when we talk about a cause of the universe as a whole, it no longer makes sense to talk about a final cause. The reason is that "the universe" is defined as everything. If the universe is intended to be for something, then whatever intended it (the conscious intender) would have to be a part of the universe itself. (That is, unless you want to limit the notion of "the universe" to refer to something less than everything; in which case, you'd have to explain how we can distinguish between the universe and whatever else is out there you would like to discuss, and why you only consider the former "the universe.")

Is it possible that some conscious being in the universe has organized the entire universe towards a particular end?

Perhaps we may one day learn to control the universe so completely that we can control its progress. We cannot conceive of how this could happen, but we cannot say it is impossible. So, it is at least not inconceivable. But there is no evidence that it has happened, or even that it could happen.

Again, this is not to say that the universe could have been created with a particular goal in mind. That, though supposed by many, would be impossible.