One of the most popular, and apparently powerful, arguments for God's existence is the argument commonly referred to as "the argument by design." Believers often point to the wonders of nature, compare them to the lesser mechanical wonders of human design, and conclude that this is evidence that the universe was created by a much more powerful Designer, that is, God.
This argument may seem persuasive, but it suffers from a number of serious flaws.
The most famous version of the argument by design is no doubt the "watchmaker analogy" published by William Paley in Natural Theology (1802). Paley first argues:
"In crossing a heath, suppose I pitched my foot against a stone, and were asked how the stone came to be there; I might possibly answer, that, for anything I knew to the contrary, it had lain there forever: nor would it perhaps be very easy to show the absurdity of this answer. But suppose I had found a watch upon the ground, and it should be inquired how the watch happened to be in that place; I should hardly think of the answer I had before given, that for anything I knew, the watch might have always been there."
Paley concludes:
"Every indication of contrivance, every manifestation of design, which existed in the watch, exists in the works of nature; with the difference, on the side of nature, of being greater or more, and that in a degree which exceeds all computation."
In this form, the argument more has the form of an analogy than a real argument, which gives it great power especially to a lay audience. However, both the analogy and the underlying argument suffers from a number of serious flaws.
Paley's analogy draws a distinction between natural objects and objects that are the products of human designers. The whole argument goes that if you should find a watch on a beach, lying in between the sand, stones, grass and waves, you would immediately recognize that it stood out from its surroundings, and that it was different. So, you would conclude it was an artifact.
The problem is that Paley suddenly turns around and says that everything in nature bears evidence of a designer! The analogy is thus self-contradictory even on the most basic level. In the analogy, the differences between the natural objects and the human artifact is what makes an observer conclude that the latter is designed. How come, then, can anyone conclude that the stones, grass and indeed the whole universe is created by a Designer, too?
Why will a human being, upon seeing a watch, conclude it is an artifact?
First, it is its simplicity, especially the simplicity in form, that makes it stand out from nature. It is not, as theists confusingly seem to think, that the watch is "complex." Compared to any living thing on that beach, it is quite simple. Human artifacts (the only artifacts we know) are not characterized by complexity, but simplicity. We use simple geometrical forms -- circles, arcs, lines -- when we create our designs, and these forms are rare in nature. In fact, sometimes we may err and conclude a natural form is artificial because it is simple and, for example, rectangular.
Second, we recognize certain patterns in designed artifacts. While I think a cave dweller would recognize the watch as a probable artifact, I think it's safe to say that we would recognize it as a certain artifact because we have seen such things before. We also know a watch when we see one, and we know from experience that these carries the name of their manufacturer, and we see no reason to doubt that. This is part of the cultural knowledge we have about what kind of products humans create. We have no comparable cultural knowledge, at least none based on actual observation and evidence, that there are any gods who create universes.
Even when put into a better form than this watchmaker analogy does the argument "by design" contain a number of serious problems:
First, theists apply the argument from design selectively. Assuming that the complexity of the universe shows it has to be design, they say that this proves the existence of an even more complex entity: God. Now, if the universe has to be created because it is complex, an even more complex deity will have to be the product of an even more powerful meta-god. Theists don't like this train of thought, and produce some ad hoc arguments with little merit.
Second, as we have remarked above with the typical "watchmaker" analogy, the argument depends on a dichotomy between artifacts and natural objects. In its original form, theists say that someone walking on a beach and find a watch, will recognize it as an artifact. But, pray tell, how can the person distinguish between artifacts and natural objects? Well, the person obviously recognizes a watch as something he already knows is an artifact, and also the simplicity of form (circular, straight lines, etc). On the other hand the person recognizes stones, grass and leaves as natural objects. Ok so far. But then theists turn around and say that these natural objects are actually designed as well! Actually, theists say, there are no natural objects, only artifacts created by some designer. Thus, the whole watchmaker argument is self-defeating.
Thirdly, and typically, arguments "by design" totally ignores the whole apparatus of explanation that modern science has provided. The theory of evolution by natural selection provides a powerful explanation of the complexities in life. While some theists reject it, it is simply not honest to pretend it does not exist, as the argument does.
Known natural processes, sometimes amazingly simple, can create objects of high complexity. Snow flakes is one example.
