Since Charles over at LGF was kind enough to link to my blog in this article, and identified me as an “anti-intelligent design” blogger, I figured it would be best to write something about the issue (other than commending Charles for his similar stance, as I did below). Since I discuss this issue in my Introduction to Philosophy class, I fortunately have some comments readily at hand…
While the intelligent design movement that concerns Charles focuses on the theory of evolution, arguments from (apparent) design to the conclusion that God exists date back at least to Aquinas, and the earliest ones had little (if anything) to do with biological evolution per se. Aquinas, for instance, argued from an Aristotelian conception of all things natural having a purpose. His argument, very roughly, went like this:
1) Natural things (even inanimate objects) nearly always act regularly, in such a way as to produce the best results.
2) So, natural things act purposefully, to achieve some goal.
3) If something acts purposefully, it either has a mind, or is designed by something that does.
4) Natural things (such as inanimate objects) do not have minds.
Conclusion: So such natural things must be designed by something that does have a mind (God)
The problem with this argument is that (2) doesn’t follow from (1), and there is no independent reason to think it’s true – at least short of accepting a Darwinian notion of “purpose” (biological function, where ‘function’ is defined in part by procreative usefulness), which would in any case apply only to biological organisms, rather than to all natural things.
A more recent argument for intelligent design of the universe which is not limited to the purported design of living creatures has to do with the extremely narrow range of physical constants that allow our sort of life to exist:
1) Life would never have evolved if certain physical constants had been slightly different.
2) There are only three possible explanations of the observed values of those constants: physical laws, sheer luck, or intelligent design.
3) Known physical laws do not explain the observed values.
4) Given all of the possibilities, it is highly unlikely that the observed values are the result of luck.
Conclusion: So the observed values are the result of intelligent design.
The problems with this argument are not as obvious as those with Aquinas’s, since this argument does not presuppose Aristotelian physics. However, there are several objections, one of which is, to my mind, fairly conclusive-
Objection to premise 2: this list might not be exhaustive; there might be more explanations (admittedly, this is not a particularly strong objection…). Objection to premise 3: maybe unknown physical laws can explain the observed values (this is a stronger objection, but still based on an assumption of ignorance). Objection to premise 4’s supporting the conclusion: even if the values are unlikely, this is no reason to believe in intelligent design. This is the strongest objection, but it calls for some explanation…
Suppose that, using a net, you catch 100 fish in a pond, all of which are larger than 6 inches. Does this data support the view that most fish in the pond are larger than 6 inches? Not if your net can’t catch smaller fish… This is known as a “selection effect”: limitations of a data collection process limits the reasonable conclusions that can be drawn from the data.
A similar limitation has to do with any single observation, in isolation from other observations. For instance, we observe life on Earth. Does this imply that life is probably found on Earth-like planets elsewhere in the universe? Well, not by itself. The problem is that our single datum entitles us to conclude neither that our situation is typical, nor that it is atypical. The point is that we may be be prejudiced by the fact that no matter how unlikely life on Earth-like planets might be, we happen to live on one that has life. Unlikely events do happen.
A similar sort of “observation selection effect” applies to the observed values of the physical constants, but here the problem is even more serious. For while we may someday have the data to be able to judge whether life on Earth is likely or unlikely (after we have observed a large number of such planets), there is only one universe to ever observe. So even if the values of the physical constants are highly unlikely, they give us no good reason to believe in intelligent design. After all, the constants having those values (or at least falling within a narrow range of values) are preconditions of there being any observations (by creatures like us) at all! We would have to observe them, whether they were likely or unlikely. Now, if they are likely (that is, if unknown physical laws make it the case that any physical universe must have similar values), this is obviously no reason to believe in intelligent design. But, less obviously, even if they are unlikely, this is also no reason to believe in intelligent design. Here’s a simple lottery analogy: it is always unlikely that the winner of a fair lottery is the winner. But this certainly doesn’t give us any reason to believe that an intelligent designer picked the winner.