The Design Argument

There are several different versions of the design (or teleological) argument, one of which is found in Aquinas's "Five Ways". But the best-known version is the one popularized by William Paley in the early 19th century. The argument goes like this:

Suppose you found yourself on a deserted island and came across a watch lying in the sand. Even though the island is deserted, you would automatically conclude that the watch could not have been the result of natural forces. It seems obvious that something as intricate as a watch, with its many different parts purposely working together, simply could not come to be without someone planning and manufacturing it. If there is a watch, then there must have been a watchmaker.

But now consider something like the human brain. It is far more complex than a watch, and its parts also work together to achieve a specific end. If we are unwilling to accept the idea of a watch coming into existence without a watchmaker, why should we not say the same thing of the human brain? Or, for that matter, of any organ or organism? Paley concludes that we have a very good reason to believe that some intelligent being created us.

The argument from design was far more convincing before Darwin. Evolution by natural selection offers a different, and much better supported, explanation for the existence of complexity in nature.

But it is not only because we have an alternative explanation that the design argument should be abandoned. The argument itself has many other difficulties, many of which were pointed out by the David Hume (1711-1776) long before Darwin.

The design argument is an argument by analogy, and the stronger the analogy, the stronger the argument. Now consider its conclusion — namely, that there is one perfect, supreme being. Is this the most reasonable conclusion to draw based on the analogy that the argument makes? Hume claimed that it is not. There isn't merely one watchmaker; there are many, and furthermore they are finite and imperfect. Thus, by analogy, a more reasonable conclusion to draw from the argument is that there are many finite, imperfect gods. Any proponent of the argument who is a monotheist rather than a polytheist therefore has some explaining to do.

An even stronger objection to the argument is this: if the existence of complex entities in this world must be explained by appealing to the existence of an intelligent designer, then the existence of such an intelligent designer, it seems, must in turn be explained by appealing to the existence of another intelligent designer, and so on ad infinitum. In other words, God requires an explanation as well, so postulating the existence of a creator God to explain our world is merely taking things one step back. The design argument therefore fails.