Theism, Naturalism, and the (Mis)uses of Parsimony
Take a parsimony argument against theism to be an argument that naturalism is to be preferred over theism on account of its simpler ontology. Naturalism, so the argument goes, posits fewer entities to explain reality than theism, and this is supposed to be a point in favor of naturalism as the best explanation of reality.
Properly understood, parsimony arguments proceed from the principle that entities should not be ‘multiplied’ or ‘posited’ beyond necessity. This principle is to be understood in a qualitative sense, so that what must not be multiplied beyond necessity are kinds or categories of entities, rather than individual entities or entities within a genus. Dawkins’ ‘gambit’ is an example of a misuse of parsimony, since in presuming that any appeal to God would entail an explanans far more complex than is required by the explanandum, he is conceiving of God as one being among others, his causal activity being homogenous with, or belonging to the same genus as, the causal activity of physical substances. But whatever else the theist may mean by ‘God’, he surely has in mind some reality that stands over and above the created order, and not some reality that is on the same metaphysical and ontological par as the world.
Equally crucial to the parsimony principle is the qualification that types of entity must not be multiplied beyond necessity. This qualification points to a distinction between the number of entities posited by a theory, and whether such entities suffice to adequately account for the data in question. It is thus no good merely to point to the fact that theory B posits more entities than theory A; one must also take into account whether there is a genuine need for the positing.
Some naturalists seem to think that merely pointing to the alleged ‘economy’ of naturalism suffices to refute theism — as if one could begin with the world and simply take out God from one’s ontology. But this ignores the crucial question of whether the number of entities posited by theism are in fact needed to explain reality — presuming, again, that naturalism is the more parsimonious account. In other words, what if there are phenomena that cannot be accounted for by the purportedly simpler hypothesis of naturalism? After all, it is not merely the claim of the theist that theism adequately explains why there is something rather than nothing, but also why the world exhibits the features that it does. Why is there a world in which things undergo change of various kinds? Why is there a world of composite substances? Why is there a world in which there is an order of efficient causes? Why is the world marked by order and regularity? Why is there beauty, such that we may appreciate it? Why are there natural desires whose fulfillment cannot be met by any natural object? Why is there a world in which truth and universals exist? Why is there a world in which people undergo transcendent experiences? Why is there one world rather than a multiplicity of disjointed realities?
And so on. the natural theologian contends, as a matter of argument, that the constituents of our experience — and beyond — owe their causality and being to some reality outside the genus of non-divine causes, so that merely to appeal to the economy of naturalism as a free-standing argument would be to beg the question against theism. In the end, parsimony arguments against theism only manage to place the burden of proof at the foot of the theist, which is not altogether interesting.
