by Michael Lopresto
It's commonplace today to think that the argument for design, with the aim of rationally establishing the existence of God, was refuted by Darwin in 1859, with the publication of The Origin of Species. This view is not only held by evolutionary biologists such as Richard Dawkins, but also top-notch philosophers such, John Mackie and Elliot Sober (and to some extent Arif Ahmed). Against this commonplace, the philosophers Simon Blackburn and Graham Oppy object that on logical grounds, David Hume (1711 – 1776), the great philosopher of the Scottish Enlightenment, dealt the argument for design its fatal blow. This was done in Hume's magnificent and delightful Dialogues Concerning Natural Religion, published posthumously in 1779, but written over the middle years of the century.
So, what exactly is the argument for design? It's an argument intended to demonstrate the existence of God—and here we're concerned only with the Judeo-Christian-Islamic God who's defined as being omnipotent, omniscient and perfectly good—from the observation that there is apparent design in the world. The term “observation” is crucial here; the argument's not intended to proceed purely from the armchair like the ontological argument is, for instance, which seeks to deduce the existence of God from the mere concept GOD (the being which no greater can be conceived), and the ancillary premise that existence is a perfection. Indeed, the world could be any way at all—it could contain much more gratuitous evil, say, and the ontological argument wouldn't claim to be any less valid. This is because the ontological argument is purely a priori: it's an argument that proceeds independently of experience (observation) of the world.
The argument for design isn't like this. Rather, it's an a posteriori argument, deploying contingent truths about apparent design garnered from experience. Indeed, the argument can't even be deductively valid, as there is no valid inference from apparent design to intentional design. So the argument needs to be empirical in nature, namely, an inference to the best explanation (explanatory inference for short), which is an empirical inference par excellence (I think it's also probably the central inference of philosophy, but that's another story). So the argument for design, for the existence of God, is that the best explanation (philosophical premise) of apparent design (empirical premise) in nature is that nature was intentionally designed by God.
