ABSTRACT
During the past 2,300 years, systematics, the science of classification, evolved in Western culture through four stages. The first was the hierarchical system introduced by Aristotle. Although this first systematics of recorded history muddled the picture somewhat by strict formal criteria based on Platonic essentials, he did establish the concept of taxonomic hierarchy-in this case the eidos of a particular form, such as horse, dog, or lion, and the genos, a class of such forms that can be regarded as part of Earth’s natural order. Aristotle recognized some 520 animal species, mostly from Greece, that were consistent with his definition of eidos.
