The combination of direct selection, kin selection, and reciprocal altruism provides the sociobiologist with a battery of speculative possibilities that guarantees an explanation for every observation. The system is unbeatable because it is insulated from any possibility of being contradicted by fact. If one is allowed to invent genes with arbitrarily complicated effects on phenotype and then invent adaptive stories about the unrecoverable past of human history, all phenomena, real and imaginary, can be explained.
Lewontin, Rose & Kamin, Not in our Genes: Biology, Ideology, and Human Nature (NY: Pantheon, 1984), pp. 261-2.
What happens if we substitute 'average evolutionist' for 'sociobiologist'?
With thanks to Walter James ReMine's remarkable exposure of evolutionary theory's varied and contradictory expressions, The Biotic Message (St Paul, Minn.: St Paul Science, 1993).