The most radical and imaginative manifestation of the evolutionary perspective is to be found in 'the survival of the fittest' theories outlined by Empedocles and Lucretius. The assorted limbs produced in 'Empedocles' first phase of generation came together, to produce monstrous creatures either with limb deformities, or of mixed species, or of mixed gender. Aristotle refers to these monsters in a section of the Physics where he is playing devil's advocate, and is putting forward a hypothetical argument for the non-teleological creation of bodily parts. In the modern theory of evolution, continuing change in the physical environment has created conditions favourable to biological transformation. Ancient zoogonies may contain very little notion of biological transformation. The belief that human beings were in the beginning very much like other animals does not in itself constitute an evolutionary perspective.