Darwin’s theory of evolution by natural selection in particular is hopelessly metaphysical, according to the rules of etiquette laid down in the Logic of Scientific Inquiry and widely believed in by practicing scientists who bother to think about the problem.
The first rule for any scientific hypothesis ought to be that it is at least possible to conceive of an observation that would contradict the theory.
For what good is a theory that is guaranteed by its internal logical structure to agree with all conceivable observations, irrespective of the real structure of the world? If scientists are going to use logically unbeatable theories about the world, they might as well give up natural science and take up religion.
Yet is that not exactly the situation with regard to Darwinism? The theory of evolution by natural selection states that changes in the inherited characters of species occur, giving rise to differentiation in space and time, because different genetical types leave different numbers of offspring in different environments…
Such a theory can never be falsified, for it asserts that some environmental difference created the conditions for natural selection of a new character. It is existentially quantified so that the failure to find the environmental factor proves nothing, except that one has not looked hard enough.
Can one really imagine observations about nature that would disprove natural selection as a cause of the difference in bill size?
The theory of natural selection is then revealed as metaphysical rather than scientific.
Natural selection explains nothing because it explains everything.
“Testing the Theory of Natural Selection” Nature March 24, 1972 p.181
Richard Lewontin (b. 1929) PhD Zoology Alexander Agassiz Research Professor at Harvard University