But we all recognise the primary foible of frail humanity - our propensity for embracing hope and shunning logic, our tendency to believe what we desire rather than what we observe.

Surely the mitochondrion that first entered another cell was not thinking about the future benefits of cooperation and integration; it was merely trying to make its own living in a tough Darwinian world

The modern theory of evolution does not require gradual change. It in fact, the operation of Darwinian processes should yield exactly what we see in the fossil record. It is gradualism that we must reject, not Darwinism.

I love the wry motto of the Paleontological Society, meant both literally and figuratively, for hammers are the main tool of our trade: Frango ut patefaciam - I break in order to reveal.

Some beliefs may be subject to such instant, brutal and unambiguous rejection. For example: no left-coiling periwinkle has ever been found among millions of snails examined. If I happen to find one during my walk on Nobska beach tomorrow morning, a century of well nurtured negative evidence will collapse in an instant.

Theory and fact are equally strong and utterly interdependent; one has no meaning without the other. We need theory to organize and interpret facts, even to know what we can or might observe. And we need facts to validate theories and give them substance.

The origin of Homo sapiens, as a tiny twig on an improbable branch of a contingent limb on a fortunate tree, lies well below the boundary.