In Mary Midgley's Evolution as a Religion (Methuen, 1985), which I'm currently rereading, she shows this clearly. Take this example, from pages 32-34.
It is a standard charge against religion that it panders to wish-fulfilment, consoling people for their present miseries by promising wonders in the future, thus dishonestly gaining support by dogmatic and unwarranted predictions. With this charge in mind, let us look at the concluding passage of an otherwise sober, serious and reputable book on the chemical origins of life on earth. The writer, a molecular biologist, having discussed evolution and described it, tendentiously but unemotionally, as a steady increase in intelligence, turns his attention to the future. Mankind, he says, is likely to throw up a new, distinct and more intelligent type, which will then become ‘reproductively isolated’. He then goes on (and I have not cheated by removing any words like ‘possibly’ or ‘perhaps’):Midgley was quoting from William Day, Genesis on Planet Earth: The Search for Life’s Beginning (East Lansing MI: House of Talos, 1979), pages 390-92. The name of the publisher made me wary, so I did some digging and found that Genesis on Planet Earth was reissued in a second edition in 1984 by Yale University Press. Day himself went on to publish some suspiciously New Age-sounding titles, as recently as 2000. Midgley says that the second edition didn't include the material she quoted above, but had a new chapter of "much vaguer but every bit as fervent, intense and evangelical [material], about the new levels to which mankind is just about to ascend" (63).He [man] will splinter into types of humans with differing mental faculties that will lead to diversification and separate species. From among these types, a new species, Omega man, will emerge either alone, in union with others, or with mechanical amplification to transcend to new dimensions of time and space beyond our comprehension – as much beyond our imagination as our world was to the emerging eukaryotes … If evolution is to proceed through the line of man to a next higher form, there must exist within man’s nature the making of Omega man. … Omega man’s comprehension and participation in the dimensions of the supernatural is what man yearns for himself, but cannot have. It is reasonable to assume that man’s intellect is not the ultimate, but merely represents a state intermediate between the primates and Omega man. What comprehension and powers over Nature Omega man will command can only be suggested by man’s image of the supernatural.Do any doubts arise? Just one. There may be a problem about timing. Major steps in evolution have been occurring at steadily decreasing intervals, and the next one may be due shortly. It must be the one the writer is waiting for. He adds: ‘On such a shortened curve, conceivably Omega man could succeed man in shorter than 10,000 years.’ Ordinary evolution, however, is too slow to allow of this startling development. So what is to be done? The reply comes briskly.
How then can Omega man arise in so short a time?
The answer is unavoidable.
Man will make him.
This is apparently a reference to genetic engineering, something specially important to those whose faith leans heavily on the dramatic idea of infallible, escalator-type evolution. They demand from that idea, not just an inspiring account of the past, but also hope for continued progress in the future. But the human race cannot be confidently expected to evolve further in a literal, biological sense. Human social arrangements, even in simple cultures, block normal natural selection. And the more elaborate they get, the more they do so. Nineteenth-century Social Darwinists attacked this problem with an axe, calling for deliberate eugenic selection and harsh commercial competition, so that the race could go back to being properly weeded and could continue to progress. As we now know, however, these schemes were not just odious but futile. The scale was wrong. Commercial competition has no tendency to affect reproduction. And as for ‘positive eugenics’, it is not possible to identify desirable genes nor to force people to breed for them. Even if it were, their spread would still be absurdly slow.
The natural conclusion is that such schemes must be dropped, that the human race must take itself as it is, with its well-known vast powers of cultural adaptation, and make the best of its existing capacities. But this thought is unbearable to those who faith in life is pinned to the steady, continuing, upward escalator of biological evolution. ‘If evolution is to proceed through the line of man to a next higher form’, as Day puts it, there simply has to be another way. That wish, rather than the amazingly thin argument he produces about recurrent evolutionary steps, is evidently the ground of his confidence.
I've noticed that a lot of people who vigorously support Darwin against Creation in the United States share this fantasy of evolution as an upward "escalator", to use Midgley's word. Despite the efforts of Steven Jay Gould, Carl Sagan, and others to explain to the educated public that Darwin's theory does not entail a linear progression from simple to complex, from lesser to greater intelligence, the fantasy is deeply rooted in many people's consciousness; it's a lot harder to dislodge, apparently, than belief in the creation myths of Genesis.