John Wilkins makes an argument that, predictably, I have to take issue with:
several things mitigate against theism from the scientific domain.
One is that if you have a purely physical explanation for an outcome X, then the explanatory role for god in producing X is no longer necessary. For example, we do not need to appeal to God’s actions to produce babies in explaining fetal development from a fertilized zygote. A purely physical account is all that we require. This is the Excluded God from the Gaps argument. Once a gap has been filled by knowledge, God is not needed.
I could point out that it’s unfair to identify theism with “The God in the Gaps”, as Wilkins is clearly doing, but refutations of the claim that the two are identical are easy to find, or even think up oneself (I’m pretty sure Wilkins himself knows a few) so I won’t dwell on the point. I’m more interested now in a tension in the argument simply as given. The initial consequence is quite true: “if there is a purely physical explanation of X, then one need not invoke God to explain X.” The truth of the consequence rests on the truth that to give a purely physical explanation/cause would not give a divine explanation/cause. But then why not simply say that these causes or explanations belong to different sciences of X? There is no problem with one thing giving rise to multiple sciences: if your X is a human being, it can give rise to human anatomy, anthropology, sociology, etc. Again, you can study this “X” that is a man as a physicist (study his mass, gravitational effects, etc) as a chemist (consider his elements) as a biologist (study his genes/ genome/ evolutionary story, etc.) as a theologian (consider his order to God) or in many other ways. The human mind isn’t the sort of thing that can exhaust any X with one and only one science, or any one set of causes.
Briefly, “science” means either
a.) the search for physical causes/ explanations of X, and/or the method appropriate to this.
b.) any rational, objective, systematic, and methodological exposition or analysis of a given X.
Wilkins’s argument shows that theism is excluded from science in the first sense, but not in the second. In other words, he shows that a method that seeks only physical causes seeks only physical causes.