Ideas of common descent and transmutation of species have existed since ancient times. The Greek philosopher Anaximander believed that humans had evolved from aquatic ancestors. Empedocles, originator of the theory of the four classical elements, proposed that natural selection was responsible for current biological forms. Roman poet and philosopher Lucretius adapted this idea, proposing that life had been formed by the chance combination of elements, the extinction of “monstrous” forms due to natural selection.
In modern times, Erasmus Darwin’s poem The Temple of Nature (1803) traced the progression of life from microorganisms to civilized society. Erasmus Darwin’s theory was taught to his grandson at Edinburgh, alongside that of Jean-Baptiste Lamarck, whose suggestion that organisms pass on acquired characteristics to their offspring was popular throughout the 19th century.
It has been suggested that the pre-Socratics had observed fossils; Erasmus Darwin and Lamarck were both distinguished natural scientists. What distinguished Darwin’s theory from theirs (and from Wallace’s) however, was the weight of experimentation and observation which underpinned his ideas. He did not originate evolution theory, but he did transform it from hypothesis into scientific knowledge.