Evolution Before Darwin
Charles Darwin was not the first thinker to suggest that living organisms evolved through time. The pre-Socratic philosopher Anaximander said as much 2,500 years ago, and the concept had become widely accepted by Darwin's own time. Nor did Darwin's originality lie with the idea that all animal life is related, or that parts of organisms or their behavior patterns are conductive to survival: by Darwin's time, such facts were constantly being appealed to by theologians as evidence for God's hand in nature. Darwin's theory of evolution triumphed because it proposed a physical mechanism to make evolution both intelligible and possible: the development of species by a process of random mutation and selective retention, known forever as natural selection.
-- Denis Dutton
from "The Art Instinct: Beauty, Pleasure, and Human Evolution"
Quoted on Sat Oct 29th, 2011