Thomas Aquinas's fifth “proof” of the existence of God (see Chapter 8) has been received as his most thoughtful. But in recent times his design argument has drawn renewed attention. Richard Dawkins addressed this and other arguments in his book The God Delusion.

Thomas Aquinas's design argument — also called his teleological argument — says that things in the world, especially living things, appear as if they have been designed. Therefore, Aquinas concluded, there must have been a designer, which you give the name of God. In Aquinas's earthy analogy, the universe and the things in it moving toward a goal are like an arrow moving toward its goal — the target. This is but one of the arguments that Dawkins goes after.

Dawkins's Treatment of Thomas Aquinas's Five “Proofs”

Without hesitating, Richard Dawkins claims that the five “proofs” asserted by Thomas Aquinas in the thirteenth century don't prove a thing. In fact, Dawkins attacks Aquinas's first three arguments — the Unmoved Mover, the Uncaused Cause, and the Cosmological Argument — in one fell swoop.

Aquinas's first argument, the Unmoved Mover, says that nothing moves without a prime mover. In Aquinas's mind, however, this leads to a chain of motions going back in time indefinitely and the only escape from the regress is God. In similar fashion the Uncaused Cause argument says that nothing is caused by itself. Since every effect has a prior cause, this chain of causes will also go on indefinitely, unless God is invoked as the first cause. Finally, his third argument — the Cosmological Argument — states that there must have been a time when no physical things existed. But it is apparent just by looking around that physical things exist now. Therefore, a nonphysical entity must have brought them into existence and this can be called God.

Dawkins's rebuttal of the argument says that each makes use of a regress and then brings God into the picture in order to terminate the regress. This move assumes without proof that God himself is immune to the regress. All of this is arbitrary, according to Dawkins.

Aquinas's fourth argument is an argument from gradation or degree. You notice in the world degrees of goodness or perfection, but these degrees can only be judged by comparison with a maximum. Since human beings can be good or bad or a mixture of both, the maximum of goodness does not reside with them. So the need for a maximum brings God into the picture, since he sets the standard for perfection. The problem with this argument is that just positing a maximum of goodness doesn't bring existence to that maximum.

In discussing Aquinas's fifth argument, the design argument, Richard Dawkins recounts how Charles Darwin was very impressed with the argument when he first encountered it as a young man in William Paley's Natural Theology. But in the years to come Darwin would pick apart the argument. Since Darwin, people no longer say that all things that look designed are designed. For evolution by natural selection produces design, from the simplest to the most complex and elegant organisms. In fact, Dawkins says, even tiny insects have nervous systems that work as if they were goal-directed systems.