How to Argue: The Watchmaker

Hello again, it's time to argue.

This week's How to Argue entry is going to tackle the classic Watchmaker analogy, first posited by William Paley in 1802:


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. (...) There must have existed, at some time, and at some place or other, an artificer or artificers, who formed [the watch] for the purpose which we find it actually to answer; who comprehended its construction, and designed its use. (...) 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.

– William Paley, Natural Theology


As is the norm (because I said so), I will begin with the lesson, and then work through the argument.

Any argument by analogy must compare concepts that are intrinsically the same across the domain of comparison.

You've probably heard the expression, "That's like comparing apples to oranges." This is a common way of saying that a comparison is invalid because the items in question are so dissimilar. Likewise, an analogy fails if you're trying to draw a parallel between concepts where similarity isn't present.

So on to the watchmaker! Essentially what William Paley (and Teleologists since Aristotle) is saying is that complexity requires a creative force (in opposition to decay), that all complex objects require a more complex creator, and thus some being greater than the universe must naturally exist.

There are a couple of issues with this argument, and I could spend a great deal of time outlining them. There is the problem of assumptions that we discussed last time (Why assume complexity to be the result of external influence, rather than an implicit force? They're equally likely.) There's the issue of causation: all creative acts imply intent. If we are ascribing the human concept of creation to the physical world, must we not also ascribe intent? If so, why is there no clear intent to the universe as we see it? (This will be an upcoming topic).

The larger issue at hand here is that what Paley presents is actually a false analogy. He fails to distinguish between natural and artificial complexity, and then equates them. Because the analogy is then completely flawed, the conclusion that he reaches is invalid.

It takes a little understanding of chaos theory, but it is perfectly reasonable to expect random systems to exhibit complex behaviors. An excellent and very simple example is the phenomenon of ice circles. Ice circles are exactly what they sound like: perfectly circular discs of ice that form in flowing water in cold conditions. A circular formation of ice is unusual, as ice has a naturally hexagonal form (which is another example of natural complexity, but is a little more difficult to demonstrate). In addition, flowing water is one of the most chaotic systems that we can observe. There aren't even supercomputers powerful enough to model the interactions.

Yet complex formations like ice circles occur constantly in the natural world. The rings of Saturn, for example, or the great red spot of Jupiter, can be easily explained despite the fact that they are massively complex (and just plain massive!) systems. Likewise, the rock that Paley struck his foot against can be seen as the natural rise of a complex object from a chaotic system. A few million years of geology, vulcanism, sediment, and tectonics are all that are required.

But Paley's saying more than that, isn't he? Though he doesn't outright extend his argument to include life, it is clearly implied. The most visible aspects of the natural world are living things. Life is very, very complex, and obviously not the result of a single process. Here again we're switching domains without switching terminology. We went from artificial complexity (the watch, made by man), to natural complexity (the stone, the result of a chaotic system), to a complex system.

While there are chaotic aspects of the biosphere, it can not be considered a chaotic system because it includes a feedback mechanism, namely reproduction. Due to this, a higher order of complex expression is expected. This is not a post on the evolutionary process, though. For further reading, see Richard Dawkins' excellent The Blind Watchmaker, which tackles exactly this issue in some depth. I just wanted to point out that once the argument changes to include life, the analogy is now so incorrect as to be laughable.

All that is needed to dispel the Watchmaker argument is the destruction of a single false analogy. This is a pervasive kind of argument, though, and one that you should keep an eye out for, and one that you should try not to repeat. Keep your apples with your apples and your oranges alone.

Be Well,
Chris.