 In terms of Aristotle's theory of four causes, the word natural is applied both to the innate potential of matter cause and the forms which the matter tends to become naturally.According to Leo Strauss, the beginning of Western philosophy involved the "discovery or invention of nature" and the "pre-philosophical equivalent of nature" was supplied by "such notions as 'custom' or 'ways'".In ancient Greek philosophy on the other hand, Nature or natures are ways that are "really universal" "in all times and places".