We encounter in Aristotle a statement of the main reason why the mechanistic interpretation of the world was unacceptable to him and to the majority of naturalists and philosophers of modern times. Causality or necessity, as he calls the principle upheld by Democritus, and chance alone cannot give a reasonable explanation of the harmony of the world, especially of the organic world, nor can they account for the undeniable finalism of living processes (Montalenti 1974: 7).