Of the several independent assertions that constitute Darwin’s “theory of evolution” in On The Origin of Species, Darwin regarded the idea of natural selection as his most important and original. After all, it alone explained how naturalistic processes could lead to the remarkable adaptations of animals and plants heretofore seen as some of the strongest evidence for God. And although the idea of evolution itself had been broached by others before Darwin, including his own grandfather Erasmus, natural selection seemed to be sui generis.There are other claims to discover natural selection, notably Alfred North Wallace.
Well, not entirely. It was anticipated by several people, including the Scottish polymath James Hutton in 1794. But the most remarkable precursor to the idea of natural selection was published by Scottish horticulturalist and agriculturalist Patrick Matthew (1790-1874) as an appendix to his book On Naval Timber and Arboriculture (1831). Although the book was about how to build ships using wood, and what kind of wood to use, Matthew added a 28-page Appendix. In that Appendix were 29 sentences that laid out what he called “selection by the law of nature”, which bore a striking similarity to the idea made famous by Darwin 28 years later.
A new book says Darwin stole the idea from Matthew.
The obvious explanation is that natural selection is an obvious idea that independently occurred to a lot of people. Indeed, it is hard to imagine a theory of life on Earth without natural selection.
What Darwin did was to articulate natural selection as a unifying principle for his other theories. My guess is that Darwin independently had the idea of natural selection, but got from Wallace the idea of using it as a unifying principle.
It is not really a scientific hypothesis that can be proved or disproved:
Creationists have long argued that natural selection has no predictive value and thus is a mere tautology stating the obvious fact that organisms that 'survive' are thereby decreed to have been the 'fittest.'See also criticisms by Karl Popper and others.