I once introduced a chapter on the so-called Cambrian Explosion with the words, “It is as though the fossils were planted there without any evolutionary history.” Once again this was a rhetorical overture, intended to whet the reader’s appetite for the explanation that was to follow. Sad hindsight tells me now how predictable it was that my remark would be gleefully quoted out of context. Creationists adore ‘gaps’ in the fossil record.
Many evolutionary transitions are elegantly documented by more or less continuous series of gradually changing intermediate fossils. Some are not, and these are the famous ‘gaps’. Michael Shermer has wittily pointed out that if a new fossil discovery neatly bisects a ‘gap’, the creationist will declare that there are now two gaps! But in any case, note yet again the unwarranted use of a default. If there are no fossils to document a postulated evolutionary transition, the default assumption is that there was no evolutionary transition: God must have intervened.
It is utterly illogical to demand complete documentation of every step of any narrative, whether in evolution or any other science. Only a tiny fraction of dead animals fossilize and we are lucky to have as many intermediate fossils as we have. We could easily have had no fossils at all, and the evidence for evolution from other sources, such as molecular genetics and geographical distribution, would still be overwhelmingly strong. On the other hand, evolution makes the strong prediction that if a single fossil turned up in the wrong geological stratum, the theory would be blown out of the water. When challenged by a zealous Popperian to say how evolution could ever be falsified, J B S Haldane famously growled: “Fossil rabbits in the Precambrian.” No such anachronistic fossils have ever been found, despite discredited creationist legends of human skulls in the Coal Measures and human footprints interspersed with those of dinosaurs.
The creationists’ fondness for ‘gaps’ in the fossil record is a metaphor for their love of gaps in knowledge generally. Gaps, by default, are filled by God. You don’t know how the nerve impulse works? Good! You don’t understand how memories are laid down in the brain? Excellent! Is photosynthesis a bafflingly complex process? Wonderful! Please don’t go to work on the problem, just give up, and appeal to God. Dear scientist, don’t work on your mysteries. Bring us your mysteries for we can use them. Don’t squander precious ignorance by researching it away. Ignorance is God’s gift to Kansas.