the perceived world. In normal usage, including language learning, the categorial system is anchored in basic objects: chair, table, man, bird, cow. These are typically learned by prototypes, rather than definitions or necessary and sufficient conditions. This basis leads to fuzzy or overlapping border. Ordinary usage handles this by various hedges. (Lakoff, 1980). While standard objects anchor a categorial system, subordinate levels emphasize differentiation, a kitchen chair as opposed to a living room chair. Superordinate levels play a distinctive role in classifications of events. By 'event' we refer to activities that are routinely categorized as distinct units. Thus the students Rosch tested listed their normal daily activities through items such as: getting dressed (putting clothes on), having breakfast (eating food), traveling to the university (using a vehicle), and attending classes. Here, superordinate terms: 'clothes', 'food', 'vehicles', 'classes' supply the normal means of categorizing activities. Such higher order activities as the classification of objects in terms of distinctive properties presupposes the establishment of the categorial system.
When categorial systems become objects of study in their own right, then the emphasis changes from particular objects to the systematization. As Hacking (2001, Sect. 2) notes, 'category' is used in a broad sense by linguists and psychologists for any class with a common name, and in a stricter sense by philosophers concerned with ultimate classes. Aristotle initiated such a systematic study and the categorial system he developed played a formative role in the evolution of both physics and biology. His list of ten categories is presented in slightly different forms in his Categories 4(1b25-2a10) and in his Metaphysics 5(1017a7-1018a20). (See Hacking, 2001, sect. 3.3) Neither account presents any justification of these ten categories as basic. Aristotle's Categories is generally treated as the introductory part of his Organon, a somewhat fragmentary collection of lecture notes in which Aristotle treats the logic of terms prior to his more mature work on syllogisms, inference, and axiomatic systems. W. Mann (2000) has recently argued that the Categories should be interpreted as the discovery of things as things. I would modify this to the claim that in the Categories Aristotle discovered a way of making individual things subjects of science3. Before considering them we should avert to an important point Mann makes. Aristotle's Categories has not been interpreted as a breakthrough chiefly because the basic points made now seem obvious. Since the treatise offers virtually no supporting arguments, the impression is given that these points were obvious even in Aristotle's day. Its revolutionary nature appears only when the doctrine presented is situated in the problematic of the late Academy, where accounts of predication supplied the tool for criticizing the ontological primacy of forms and tackling the foremost problem of the day, making change intelligible.
The striking new claim is that among entities in general ( ), concrete individual things are the really real, the fundamental entities (). Though this term is generally translated 'substance', this translation effectively imposes Aristotle's later metaphysics, rather than the problematic term he shared with Plato. As suggested by Hacking, Aristotle's earlier use of this term will be translated 'what a thing is' or 'whatness'. The crucial citation is (Categories, 2b 5-6): “Thus everything except primary whatness is either predicated of primary whatness, or is present in them, and if these last did not exist it would be impossible for anything else to exist.”
3 I am also relying on Sellars' privately circulated monograph, "Aristotle's Metaphysics: An Interpretation", and, with considerable reservations, on Anscombe (1961), chap. 1