The Argument from Design

The Gist

The Official Argument

As I described in class, I think it's best to view the Design Argument as, officially, an "inference to the best explanation". It relies on a general principle that is is reasonable to believe the best explanation of a range of observations (premise 1, below). I reconstructed the "official argument" as follows: As we saw with the Ontological and Cosmological arguments, the Argument from Design, even if successful, would only be a first step in showing that God exists. That is, if the Design Argument is successful it only establishes the existence of designer of the universe. More argument (a second step) would be needed to show that this designer has any of the characteristics we might want to ascribe to "God". (And as we will see below, we might question the prospects for this second step.)

The Watch Analogy

As it stands the official argument may be less than convincing. What kinds of examples of "complex harmony" does the argument have in mind? And why should we think that the best explanation of these examples is that the universe had a designer?

To motivate the Design Argument, proponents usually discuss an analogous argument involving the discovery of a watch in a forest. (In the article we read for class, Paley, in giving his own version of the argument from design, spends the bulk of his discussion on the watch case.) The point of this analogy is to help motivate the claim that the best explanation of something's "complex harmony" is that the thing had a designer.

The set-up is as follows: Let's say you were walking through the woods and you came across a watch sitting on a stump. Upon inspection of the watch, you would find that it exhibits a great deal of "complex harmony". Not only would you find that it is a complex bit of machinery, you would see that the gears seem to be working together. The complexity seems to be serving some function.

Paley claims that the reasonable thing to infer is that the watch had a designer. I construed his point as an argument by analogy to support premise 3 of the Official Design Argument:

Assessing the Official Argument

Let's turn now to the assessment of the Argument from Design. To begin, let's focus our attention on the "official argument". (We'll puzzle over the watch analogy below.)

Remember our discussion of arguments. If you'll recall, there are two ways of objecting to an argument. You can either question the truth of one or more of the premises (questioning the "soundness" of the argument) or you can attack the reasoning (questioning the "validity" of the argument).
The reasoning in the official argument is valid. If those premises are true, then the conclusion must also be true. But are those premises true? Let's look at each one in turn:

Premise 1. Premise 1 is a statement of the "principle to the best explanation". As I mentioned in class, there are some reasons for questioning this premise. However, for our purposes, I think we should just give this one to the proponent of the Argument from Design. The principle does have a good deal of plausibility. And as we will see, there are plenty of other possible objections to the Design Argument.

Premise 2. Premise 2 states that we observe "complex harmony" in the universe. In class, I briefly discussed a few possible examples of "complex harmony" that a proponent of the Design Argument might point to:

Premise 3. Premise 3 is the crucial (and most questionable) premise of the argument. This premise states that the "complex harmony" that we find in the universe is best explained by the presence of a designer. But we might question whether God’s existence provides the best explanation of what we observe in the universe.

First, we might raise some general worries about this claim. More precisely, we might question whether it really supports the explanation that the theist wants to give, namely that the universe has a single and presently existing designer.

Second, as a more substantial objection, we could question the claim that God’s existence provides the best explanation of what we observe in the universe on a case-by-case basis. That is:

Depending on what examples of “complex harmony” we look at, we might very well come up with rival explanations.
(As an example I discussed in class, Darwin's theory of natural selection provides a quite elegant explanation of the "complex harmony" we find among various species. The point is that Darwin's theory provides a rival, and perhaps superior, explanation than the claim that the universe had a designer. As Davies puts it in our book, "We may take [the living organisms we know about] to manifest design. But what accounts for the appearance of design is the disappearance of the unfit. There are no hostile witnesses to testify against design. They have all been killed off." p. 249)

Questioning the Analogy

The Official Design Argument is often strengthened by appealing to the watch analogy. But, as I described in class, there are a couple of ways we might question any instance of analogical reasoning.

One way to question the reasoning is to question the analogy itself. That is, we might question whether the case of the universe is really that similar to the case of the watch. Notice, there are several disanalogies between the two cases. In class, I focused on two disanalogies:

The preceding two points both show ways in which the two cases (the universe case and the watch case) are dissimilar. But remember, to block an argument by analogy it isn't enough to simply point out some differences, you need to show that these differences are relevant to the conclusion drawn in each case.

Paley, in defending the Design Argument, attempts to deal with each of the disanalogies described above. He does so by modifying the original watch case in a way that gets rid of the differences. (We might puzzle over whether his response is ultimately successful. One worry I raised in class is that Paley's continued modifications may leave it questionable whether the watch really serves as an "uncontroversial case".)

The Prospects for "Step 2"

But even if the above objections can be dealt with, there's a serious worry about whether the Design Argument can really get the theist what she wants. Remember, the Argument from Design is only the first step in showing that God exists. That is, if the Design Argument is successful it only establishes the existence of designer of the universe. More argument (a second step) would be needed to show that this designer has any of the characteristics we might want to ascribe to "God". And we might question the prospects for this second step.

As a preliminary point, notice that most theists want to say that there is one single God, and that he presently exists. But how could either of these claims be established on the basis of a Design Argument. To make use of the watch analogy, most watches are designed and manufactured, not by a single person, but by a team of people. And of course, I have no way of knowing whether the designer of the watch is still alive.

Problem of Evil

A more serious worry is (one version of) what's known as the "Problem of Evil".