For evolution you need three basic things:
- Competition between different versions
- Selection based on a test of fitness.
And the 'winner' is the version which produces the most copies and eventually vanquishes the other version.
Of course, this is normally thought of in terms of genes and biology, but genes are not the only things which meet these three requirements. Another is scientific hypotheses.
Science can (should?) be seen as a body which consists of hypotheses which are either still in competition or, for all practical purposes have played out the competition and determined the winner. As the hypotheses compete and emerge as winners, they give rise to new hypotheses and so the whole body of science progresses and develops and tends toward a closer approximation to the truth.
I'll take a simple idea to illustrate this.
The competing hypotheses. There was once a time when most people in the West believed the earth was flat, despite the fact that Eratosthenes had shown it not to be in about 240 BCE. The two ideas - flat earth and spherical earth - both existed in the ideas pool. The flat earth idea predominated but never entirely exterminated the spherical earth idea. The flat earth idea had been useful to an extent but it meant that people were afraid of falling over the edge, so progress in exploration was limited. These were versions of the 'shape of earth' idea.
The test for fitness. Gradually, as more and more knowledge was accumulated more and more people came to hold to the spherical idea. Even Saint Augustine of Hippo (354-430 CE) seems to have accepted that the earth was spherical. He went so far as to argue that there could not be people living on the far side of earth because, since they must have been descended from Adam they would have had to build ocean-going ships to take them there.
He said, "It is too absurd to say, that some men might have taken ship and traversed the whole wide ocean, and crossed from this side of the world to the other, and that thus even the inhabitants of that distant region are descended from that one first man", but I won't dwell too long on Saint Augustine's inadvertent ridiculing of the idea that everyone is descended from the biblical Adam.
The point here is that in the competition for ideas, the spherical earth idea was winning because, with more information, more people became convinced it was the best explanation of the evidence. For a scientific hypothesis, this is the only real test for fitness.
So, by 1492 Christopher Columbus not only knew the earth was round but was prepared to prove that sailing West was the quickest way to China, thinking earth was much smaller than it turned out to be. In so doing he not only failed to reach China but thought he had missed and was in India; and so misnamed the aboriginal inhabitants of the Caribbean and the New World which he had accidentally discovered in the process.
Replication. That just about convinced all but a few remaining die-hards that earth is spherical, but a few lingered on until we were able, with science, to go out into space and look at earth from a distance and see that it is spherical. Now belief in a flat earth is more likely to be a symptom of delusion and insanity than of a rational thought process. The idea of a flat earth is now replicated in the minds of just about everyone who ever took a basic geography lesson or saw a photograph of earth from space. No one in their right minds would think of telling their children anything but that earth is spherical. (Actually an oblate spheroid, just to deter hair-splitters and creationists looking for something to distract attention with).
We now have what amounts to a scientific 'Law'. The Spherical Earth Theory is not seriously disputed by anyone with any knowledge of the facts. It is a comprehensive, falsifiable theory to explain the observed facts, supported by evidence, able to make and test predictions, and it has not been falsified.
So the body of science was changed by a Darwinian evolutionary process in which one idea won in a test for fitness and came to dominate the ideas pool to the almost total exclusion of its rival. The body of science has so progressed, making other hypotheses like plate tectonics, weather system generation and ocean currents possible.
Exactly the same principle can be applied to any scientific ideas and competing alternative hypotheses, whether it's about the best fuel for a rocket motor to get the the moon, the best rubber for a car tyre, the best Internet Transfer Protocol or the best explanation for the origin of living things.
Without this Darwinian evolutionary process, 'science' would be a primordial soup of conflicting and contradictory notions none of which could be said to be any better than the other, and there would be no basis for using new knowledge that competitive selection of ideas produces, to develop new hypotheses, and so no progress would be possible. Indeed, there would be no basis for even describing a 'body of science'. Science and scientists could not exist.
So, if you imagine you don't believe in evolution you have to explain why science knows more now that it did before; why it can give us modern technology like radios, television and telephones where previously it could not; why we have better medicine now than we used to have and why I can post this blog on the Internet for you to read on your computer or mobile when, just a few years ago, this would have been literally unthinkable.
Where did that idea come from?
It evolved by Darwinian evolution out of earlier, less complex and less well defined ideas built themselves on earlier hypotheses. The fossils of this evolutionary process can be found in old science books and journals, in museums of technology and maybe in the minds of old, retired scientists. Deformed and mutant forms of these ideas can frequently be found in the minds of creationists, priests and religious apologists and their followers.
If you dispute this, you have to explain why the process I outlined is not a Darwinian evolutionary process. Good luck with that.