The theory is rooted in pure chance

The argument

Critics of evolutionary theory argue that, stripped of its technical vocabulary, the theory asks us to believe that blind chance built the living world. The raw material of evolution is random mutation — copying errors with no foresight, no direction and no goal. Natural selection can only choose among whatever variations chance happens to serve up. At its foundation, on this argument, the whole edifice therefore rests on accident: every eye, wing, enzyme and brain must trace back to an unplanned series of genetic typos that just happened to be useful. Proponents of this view contend that the numbers do not work. Functional proteins are precise sequences of hundreds of amino acids, and the overwhelming majority of possible sequences do nothing at all. The astronomer Fred Hoyle famously compared the chance assembly of a living cell to a tornado sweeping through a junkyard and assembling a Boeing 747. Intelligent design advocates such as the biochemist Michael Behe press the same intuition: that systems of many interdependent parts cannot plausibly be built by undirected increments, because the intermediate stages confer no advantage for selection to favour. Defenders of Darwin reply that selection is the opposite of chance, accumulating small advantages non-randomly. But critics answer that this only relocates the problem: selection cannot act until chance has already produced something functional, and the origin of the first self-replicating life remains, on any account, a matter of luck. A theory whose creative engine is randomness, they conclude, is not an explanation of life's order but a confession that none exists.

Premises

Counter-arguments

Biologists reply that the argument mischaracterises the theory. Mutation is random, but natural selection is the opposite of chance: it non-randomly preserves the variants that work and discards the rest, so cumulative selection can assemble complex structures over many generations that pure chance never could in one step. Hoyle's tornado-in-a-junkyard image and Behe's irreducible complexity have been widely rejected, because proposed 'irreducibly complex' systems have documented stepwise evolutionary pathways. The origin of the first self-replicating molecule (abiogenesis) is, moreover, a separate question from evolution by natural selection, so conceding uncertainty there does not touch the theory.

Rejecting the premises

[Rejecting P1] Selection acts non-randomly on random variation, so adaptations are not products of 'pure chance.' [Rejecting P3] Cumulative selection builds function incrementally, and the separate problem of life's origin does not show natural selection relies on luck.