http://www.aeonmagazine.com/world-views/does-life-have-a-purpose/

Does life have a purpose?

Nobody expects atoms and molecules to have purposes, so why do we still think of living things in this way?

by Michael Ruse

"So what of now? Today’s scientists are pretty certain that the problem of teleology at the individual organism level has been licked. Darwin really was right. Natural selection explains the design-like nature of organisms and their characteristics, without any need to talk about final causes. On the other hand, no natural selection lies behind mountains and rivers and whole planets. They are not design-like. That is why teleological talk is inappropriate, and why the Gaia hypothesis is so criticised. And overall that is why biology is just as good a science as physics and chemistry. It is dealing with different kinds of phenomena and so different kinds of explanation are appropriate. There was a Newton of the blade of grass and his name was Charles Darwin.

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But historical teleology — the question of whether evolution itself takes a direction, in particular a progressive one, is a trickier problem, and I cannot say that there is yet, nor the prospect of there ever being, a satisfactory answer. One popular way to explain the apparent progress in evolution is as a biological arms race (a metaphor coined by Julian Huxley, incidentally). Through natural selection, prey animals get faster and so in tandem do predators. Perhaps, as in military arms races, eventually electronics and computers get ever more important, and the winners are those who do best in this respect. The British evolutionary biologist Richard Dawkins has argued that humans have the biggest on-board computers and that is what we expect natural selection to produce. But it is not obvious that arms races would result in humans — those physically feeble and mentally able omnivorous primates. Nor that lines of prey and predator evolve in tandem more generally."