Replicators and Vehicles

he theory o f natural selection provides a mechanistic, causal account of how living things came to look as if they had been designed for a purpose. So overwhelming is the appearance of purposeful design that, even in this Darwinian era when we know "better," we still find it difficult, indeed boringly pedantic, to refrain from teleological language when discussing adaptation. Birds' wings are obviously "for" flying, spider webs are for catching insects, chlorophyll molecules are for photosynthesis, DNA molecules are for... What are DNA molecules for? The question takes us aback. In my case it touches off an almost audible alarm siren in the mind. If we accept the view of life that I wish to espouse, it is the forbidden question. DNA is not "for" anything. If we wish to speak teleologically, all adaptations are for the preservation of DNA; DNA itself just is. Following Williams, I have advocated this view at length, and I do not want to repeat myself here. Instead I shall try to clear up an important misunderstanding of the view, a misunderstanding that has constituted an unnecessary barrier to its acceptance