Too many people take the so-called theory of intelligent design seriously, which is unfortunate since nobody who takes a scientific view of the world should, and everyone ought to take a scientific view of the world. As many have argued, ID theory is not, properly, a theistic explanatory model. However, I am not convinced that this is the case, and for two primary reasons. (Though, I find that insofar as ID theories are not theistic models, they actually suffer from more problems, so they really ought to welcome theistic interpretations. But this we may skip for now.) First, the correlation between theism and ID theory is too great for it to be an accident of honest inquiry. The overwhelming majority of ID theory proponents are theists, and theistic conceptions of god are, not surprisingly, suitable candidates for the intelligent designer. Second, the Discovery Institute, the main intellectual impetus behind ID theory in the English speaking world, published The Wedge, wherein they explicitly advocate for a theistic interpretation of ID theory. (FYI: One may read the document here: The Wedge.)
In any case, what is to follow is a rough and ready argument against theistic explanatory models.
An explanatory model must meet at least three conditions: (1) it ought to contain less information than the previous level of explanation; (2) it ought to facilitate more testable predictions than previous levels of explanation; and (3) it ought to contain enough information so as to permit the deduction of testable predictions.
E.g., the molecular theory of chemistry far surpasses earlier substance theories of matter in (1) – (3), and we can further reduce the former to the atomic theory of matter, which we can even further reduce to the Standard Model.
Theistic models, however, fail to be explanatory in this way because, insofar as they attempt to satisfy (2), they satisfy (3) in a manner which violates (1). To clarify, let us begin with an example.
Take the fine tuning argument (FTA) for the existence of god. Proponents of the FTA claim that the existence of a universe suitable for life is more likely than not given the existence of god. [Insert here all the prima facie appropriate and impressive numbers on this-and-that finely and seemingly improbably balanced physical constant.] That is to say, given god, one should expect that the universe one inhabits would exist, and, given not-god, one should not expect that the universe one inhabits would not exist. Our universe exists. Thus, god likely exists.
This argument is a bit too swift. Technically, nothing besides the existence of a supernatural agency follows from the existence of a supernatural agency. If we are to deduce the existence of the life permitting universe we inhabit from the existence of god, we must add at least one assumption: god desired and thus intended to bring about a life permitting universe. (We may find that we have to add the further supposition that god desired and thus intended to bring about intelligent beings (though, not necessarily homo sapiens), but for present purposes we need not consider this.] Otherwise the existence of a life permitting universe is no more evidence for a god than the existence of a life prohibiting universe, since, ceteris paribus, the existence of a life permitting universe would be a statistical accident; god created a random universe (through whatever process) and let matters unfold in appropriately deterministic ways. To be sure, god could have created an infinite amount of universes and the current one we find ourselves in would be just one of many, in which case we could not differentiate the theistic state of affairs from the multiverse, quantum loop theory of infinitely many universes, or any other non-theistic state of affairs.
Now, given the existence of god and the assumption that god intended to bring about a life permitting universe, we can very well deduce the current universe. Which is to say that a theistic model which incorporates the assumption of god’s intentions satisfies (2). However, the problem is that the assumption adds quite a lot of information to the theistic model; so much information, in fact, that (1) above is violated.
The assumption turns the theistic model into a psychology-based model. Now, the only psychologies with which we are familiar are very complex phenomena; perhaps the most complex phenomena know to modern science. Moreover, the only pyschologies with which we are familiar are those of material beings with material brains. We know what it is like for material beings to have psychologies: we can dissect, image, and otherwise interact with brains and identify brain structures which control emotions, intentional states, reason, etc. In short, we can identify the physical systems which give rise to human psychology.
We can also explain human psychology in terms of evolution and social factors. We can further explain human psychology in terms of physiology and brain chemistry. At each level- from the evolutionary and social to physiology and brain chemistry, right on down to the molecular theory of chemistry and atomic theory of matter and the Standard Model- we can reduce the amount of information, but retain enough information, while retaining the ability to make testable predictions. In short, we can satisfy (1) – (3).
However, with god, we cannot avail ourselves of any simpler physiological, biological, social, molecular, or atomic theory; there are no god brains; no god particles; no god societies (presumably there are none; the standard arguments for god all allow for many gods, though, and thus for a society); no general principles by which to explain god’s psychology. Insofar as one makes assumptions about god’s intentions, one complicates the explanatory model in such a way that it no longer remains explanatory. (Indeed, one cannot think of anything in more need of explanation than god.) The explanatory state of affairs would be thus: we have explained in a relatively economical way through our scientific theories the origin of our universe, but then fastly complicate our model by postulating the existence of a god and making necessary assumptions about its psychology.
Theists invariably attempt to obviate this problem by making recourse to divine simplicity, which amounts to little more than bare assertion in trying to simplify their model: “god is simple because, well, he just is, otherwise he would not be god!” But of course this is fraudulent and transparently so; anyone can claim simplicity without explaining the details.
To conclude, theistic models fail to explain anything since they fail, inevitably, to satisfy (1) – (3).