Friday, May 28, 2010

TGD: Chapter Three - Degree and Design

Last week I said I would talk about the rest of Aquinas' proofs and the ontological argument for God's existence. Unfortunately, I seem to have bit off more than I can chew. I've managed to cover Aquinas' last two proofs but the post is already getting long. I will have to write about the ontological argument next week. I'm sorry for the delay.

Last week I had just finished discussing the first three of Aquinas' proofs for God's existence. Today I'm going to pick up right where we left off.

Aquinas' fourth proof is the argument from degree. This argument states that things vary in how perfect or how good they are. He argues that there must be a being which is the most good, which is the source of all things good and of all that exists. This being we call God.

This is Dawkins' reply to the argument from degree: "You might as well say, people vary in smelliness but we can make the comparison only by reference to a perfect maximum of conceivable smelliness. Therefore, there must be a pre-eminently peerless stinker, and we call him God."

Not only is Dawkins' reply funny, but it gets at the main problem with the argument from degree. Aquinas makes the assumption that existence is a form of perfection. From this he is able to conclude that the source of all that exists is the source of all things good and perfect. This is the same sort of dodgy logic that the ontological argument relies upon.

So I don't think the argument from degree works as a proof of God's existence. However, I think it raises some impportant questions. How did humans first learn to be good? What is the ultimate source of moral goodness? These are questions that need to be addressed.

At last we come to Aquinas' fifth proof. This is the teleological argument, or the argument from design. Before I write about what Dawkins has to say, I want to describe the argument and give some background.

In this argument Aquinas argues that inanimate objects act according to a purpose, because they always behave according to the same pattern. He argues that this did not come about by chance. He argues that there must be an intelligence behind the universe that guides inanimate objects to behave in predictable patterns.

Aquinas' argument relies upon the idea, common in his time, that objects behave according to a purpose. These days we don't think of objects as having a purpose. It may seem silly to say that objects have a purpose but does it make any more sense to say that inanimate objects behave according to natural laws? Doesn't the existence of natural laws imply the existence of a supernatural lawgiver?

Still, so long as those natural laws seem arbitrary most people are willing to accept that they exist. If we argue that God exists because some arbitrary set of natural laws exist that's just a rehash of the cosmological argument, which I talked about last week. However, if the natural laws seem contrived; if the natural laws appear to have been carefully set with a particular purpose in mind; then that would be evidence for an intelligence guiding the universe.

This is the summary Dawkins' gives of the argument from design: "Things in the world, especially living things, look as though they have been designed. Nothing that we know looks designed unless it is designed. Therefore there must have been a designer, and we call him God." Dawkins points out that the theory of evolution blows this argument out of the water completely.

Of course, Dawkins' version of the argument is very different from Aquinas' original argument. I would accuse Dawkins of deliberately constructing a straw man, but I know exactly where he got this version of the argument. This form comes from creationists who stubbornly refuse to accept the theory of evolution. Dawkins has spent much of his career debating against creationism.

On the (relatively) small scale, evolutionary theory works as an explanation for the complex, seemingly designed, nature of life. But on the cosmic scale evolution doesn't solve the problem of design, it just moves it. In order for evolution to work, the laws of the universe have to be just right. The cosmological constant has to allow for the slow, steady expansion of the universe, in order to allow stars to form and generate the elements required for life. Similarly, if the force of gravity were stronger or weaker then it becomes impossible for life-sustaining stars to exist, making it impossible for life as we know it to exist.

So we see that the laws which govern our universe were not chosen arbitrarily. Instead it seems that they were finely tuned to allow life to form. This gives us reason to believe that there is an intelligence guiding the universe. This argument doesn't prove the existence of any specific deity but it demolishes the claim that God doesn't exist.

Next week: Saint Anselm makes his appearance.


  1. Jimmy wrote: "So we see that the laws which govern our universe were not chosen arbitrarily. Instead it seems that they were finely tuned to allow life to form."

    This is only true given our current understanding of physics. The presence of fiddle factors, like the relative strength of gravity to electro-magnetism is a defect in the theory. Some physicists try to explain it using a teleological argument (or multiple universes, which amounts to the same thing in my view), but most physicists are not happy with this state of affairs.

    So suppose in the future there is a unified theory that explains the some of these fiddle factors. Would that weaken the argument for the existence of God?

  2. I don't think it would. At least, not by very much. Let's suppose there was a theory where the cosmological constant, the ratio between gravity and electromagnetism, and all the other fundamental constants are dependent on one another. So now you've got it down to one fundamental constant which determines all the other constants. You can still ask, why does this constant have the value it does, and not some other value?

    More than that, we could ask, why do the physical laws work the way they do? So long as we are admit the possibility that the universe could have been different from the one we live in, the argument works. Degenerate universes, ones that don't allow conscious life to evolve, will always be simpler and therefore more likely than universes that support conscious life.