richard_dawkins_-_the_god_delusion

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climb, but on the other side is a gentle slope to the summit. On the
summit sits a complex device such as an eye or a bacterial flagellar
motor. The absurd notion that such complexity could
spontaneously self-assemble is symbolized by leaping from the foot
of the cliff to the top in one bound. Evolution, by contrast, goes
around the back of the mountain and creeps up the gentle slope to
the summit: easy! The principle of climbing the gentle slope as
opposed to leaping up the precipice is so simple, one is tempted to
marvel that it took so long for a Darwin to arrive on the scene and
discover it. By the time he did, nearly three centuries had elapsed
since Newton's annus mirabilis, although his achievement seems,
on the face of it, harder than Darwin's.
Another favourite metaphor for extreme improbability is the
combination lock on a bank vault. Theoretically, a bank robber
could get lucky and hit upon the right combination of numbers by
chance. In practice, the bank's combination lock is designed with
enough improbability to make this tantamount to impossible -
almost as unlikely as Fred Hoyle's Boeing 747. But imagine a badly
designed combination lock that gave out little hints progressivelythe
equivalent of the 'getting warmer' of children playing Hunt the
Slipper. Suppose that when each one of the dials approaches its
correct setting, the vault door opens another chink, and a dribble
of money trickles out. The burglar would home in on the jackpot
in no time.
Creationists who attempt to deploy the argument from improbability
in their favour always assume that biological
adaptation is a question of the jackpot or nothing. Another name
for the 'jackpot or nothing' fallacy is 'irreducible complexity' (IC).
Either the eye sees or it doesn't. Either the wing flies or it doesn't.
There are assumed to be no useful intermediates. But this is simply
wrong. Such intermediates abound in practice - which is exactly
what we should expect in theory. The combination lock of life is a
'getting warmer, getting cooler, getting warmer' Hunt the Slipper
device. Real life seeks the gentle slopes at the back of Mount
Improbable, while creationists are blind to all but the daunting
precipice at the front.
Darwin devoted an entire chapter of the Origin of Species to
'Difficulties on the theory of descent with modification', and it is