What was Aristotle's reasoning behind choosing the types of categories(substance, quantity, etc.)? They seem reasonable, however was the decision based on prior teachings from Plato? The grammatical structure of Greek?
▻ THE CATEGORIES - A MIXED AND ARBITRARY LIST ?
The late Oxford philosopher, HA Prichard, referred to Aristotle's categories as 'an unrelated chaos in which it is impossible to acquiesce'. The categories and their apparent lack of an organisational principle also irked Bertrand Russell. The list of categories looks and might actually be unrefined and arbitrary. We can add that, except at 'Topics', I.9,103b22, Aristotle does not repeat the full list, nor does he make significant use of it elsewhere. But nor does he reject or revise it.
▻ PHILOSOPHICAL BACKGROUND TO THE CATEGORIES
Some background-setting is needed; and I'll try to do this briefly.
In Aristotle's view reality is ultimately made up of individual things, individual physical entities, defined by their form. Each basic individual is an essence or substance (ousia)*. There are indefinitely many substances. But a substance cannot exist without properties or from a different angle things that are saying or predicabke if it.
If I am a substance, I cannot exist without properties : I must be tall or short, bulky or slim, I must be somewhere and be there at a time, I must be older than X and younger than Y. As Aristotle summarises in 'Metaphysics', XIV.2.1089 b23, I must have states (pathe) and relations to other things (ta pros ti). This is the key to the categories.
▻ THE CATEGORIES
The theory of categories is an attempt to list all the possible kinds of properties a substance can have. He lists ten, probably familiar but I'll repeat them just in case : substance (ousia), quantity (poson), quality (poion), relation (pros ti), where (pou), when (pote), position (keisthei), possession (echein), action (poiein), and undergoing or being acted on (paschein). Examples : substance (a human being), quantity (three miles), quality (blue), relation (half), place (Times Square), time (today), position (standing), possession (having an aptitude, knack, habit...), action (eating), being acted on (being fed).
Aristotle takes these to be the mega-classes, if the phrase can be allowed, the highest or most general classes (genera) to which properties - all properties - belong and to which predicables pertain.
▻ PHILOSOPHY AND LANGUAGE
There is nothing on the surface wrong with what Aristotle is trying to do here. The problem is that the list appears to, and probably does, lack an organising principle. Why these ten categories and not five or fifteen ?
It is almost certain that grammatical considerations, features of language, played a major part in Aristotle's enumeration of categories. The German scholar, Friedrich Trendelenburg (1802-72), took the view that four of the categories (substance, quantity, quality, relation) derived from names and adjectives; another four (position, possession, action and being acted on) from verbs; and time and place from adverbs. (Friedrich Trendelenburg, Geschichte der Kategorienlehre, in Historische Beitrage zur Philosophie, v. I (Leipzig: Bethge, 1846. The 'a' in 'Beitrage' needs an umlaut which I can't type here.) In short, Aristotle appears to have worked inductively from these grammatical groups - names, adjectives, verbs and adverbs - to produce his kategoria or categories.
J. Owens, 'Aristotle on Categories', The Review of Metaphysics, Vol. 14, No. 1 (Sep., 1960), pp. 73-90.
A. C. Lloyd, 'Aristotle's Categories Today', The Philosophical Quarterly (1950-), Vol. 16, No. 64, History of Philosophy Number (Jul., 1966), pp. 258-267.
- In 'Categories' ch. 5 Aristotle draws a distinction between primary substance, an individual physical entity, and secondary substance. A secondary substance might be a species or genus. For instance, a human being such as Socrates would be a primary substance; humankind, the class of humans, would be a secondary substance.
I'm not sure if it is right to put the categories somewhere in a discrete cubby, as though Aristotle's thought were not whole. Some say that is justified by the fact that Aristotle's writings are received in a disconnected and scattered fashion and can not be considered as a "system".
Aristotle studied all the thinkers who came before him in the Greek world. And considered Plato as a "epigone" of all of them, and one must think as a kind of great synthesizer.
His chief influence was, however, common opinion, which he though a very reliable measure. But he went beyond this in a peculiar manner, unlike those who tried to ascend from ordinary opinion through diological discussion (e.g., Socrates), he attempted to do so by vision, the eyes of the soul, which he distinguished from observation of Nature. Later, nearer to our own time, a sort of so-called phenomenology was read back into Aristotle, or was it already there?
Predication in Aristotle simply means "I say something about something", so one must not think so-called grammar, as it were, played any great role. He looked at words, such as "phusis", nature, and asked, what is the essential meaning of this word, the most important meaning. He tried to locate place things, through definition, in the world, in such a way as to know the world order, how they stood in the cosmos. For instance by understanding the genus of man as animal, and within the animal, the particular difference or essence of man as reason. Likewise the categories are orienting devices, as it were.
The connection with Aristotle to linguistic analysis is more due to the 17th century discovery of Evolution (or drift) in languages. Which escalated up until the time of Heidegger who made an uncommonly influential and profound (which is not to say necessarily true) study of Aristotle, with respect to a claim concerning the "primordial" or "orgniary" meaning of Greek, if you like, "grammar". Heidegger would never have called it that. Instead speaking of Greek Language. There's an overlay, of Aristotle's etymological analysis, and modern claims to "understand Aristotle better than he understood himself", in the current scholarship on Aristotle. In the last analysis, so to say, the two blend imperceptibly and inseparably.
It's hard to tell "our" Aristotle from the Aristotle.