id	author	title	date	pages	extension	mime	words	sentences	flesch	summary	cache	txt
en-wikipedia-org-9348		Category of being - Wikipedia			.html	text/html	4548	518	63	Secondly, following Porphyry's likening of the classificatory hierarchy to a tree, they concluded that the major classes could be subdivided to form subclasses, for example, Substance could be divided into Genus and Species, and Quality could be subdivided into Property and Accident, depending on whether the property was necessary or contingent.[3] An alternative line of development was taken by Plotinus in the second century who by a process of abstraction reduced Aristotle's list of ten categories to five: Substance, Relation, Quantity, Motion and Quality.[4] Plotinus further suggested that the latter three categories of his list, namely Quantity, Motion and Quality correspond to three different kinds of relation and that these three categories could therefore be subsumed under the category of Relation.[5] This was to lead to the supposition that there were only two categories at the top of the hierarchical tree, namely Substance and Relation, and if relations only exist in the mind as many supposed, to the two highest categories, Mind and Matter, reflected most clearly in the dualism of René Descartes.[6]	./cache/en-wikipedia-org-9348.html	./txt/en-wikipedia-org-9348.txt