When Charles Darwin published On the Origin of Species in 1859, the Bishop of Worcester's wife was most distressed. 'Let us hope it is not true', she is said to have remarked. 'But if it is, let us pray that it does not become generally known!'
—R. D. Keynes
In the days before pocket calculators, few people who used the arithmetical procedure for extracting square roots could justify that procedure, though they got the right answers. But the procedure for extracting square roots does not affect the way in which we see ourselves and our place in the world; the theory of evolution by natural selection does. Yet, although Darwin's theory is believed by a substantial majority of educated people in the western world, it is doubtful whether more than a small fraction of those who do believe could, if asked, produce much evidence to justify their belief.That would not matter if the theory were not being continually questioned, or if it were less influential on our thinking. Indeed, Freud thought that the three most severe blows that scientific research had inflicted on 'man's craving for grandiosity' were those associated with the work of Copernicus (which displaced the earth from the centre of the universe), the work of Darwin (which displaced humans from the privileged position conferred by the first two chapters of Genesis), and his own work. Not many people now would agree with Freud's assumption of the third place in the trio, but there can be no doubt about the claims of Copernicus and Darwin. And though, unlike Copernicus's “De revolutionibus orbium coelestium”, Darwin's writings were never placed on the Index, and Darwin himself was to be buried in Westminster Abbey with a brace of dukes and an earl among his pall bearers, it is his work that necessitated the more profound readjustments of orthodox religious beliefs.
(From "An Anatomy of Thought: The Origin and Machinery of the Mind" by Ian Glynn)