Except from Chapter 4 of :


(in press, Westport, CT: Greenwood Press)


Christopher D. Green, York University
Philip R. Groff,
University of Toronto


Aristotle's Work


Logic, metaphysics, and physics

As implied above, before we can make much sense of Aristotle's views of the psychę, we must first cover some basic elements of his philosophy and science. This is because terms that play crucial roles in his psychological thought -- such as "matter," "form," "substance," "cause," and "category" -- are first elucidated in his more fundamental works. Thus, we will discuss such matters here before going on to an examination of his main psychological text, De Anima.

The first book, conceptually if not chronologically, of Aristotle's work on logic is called the Categories. True to its title, it is an attempt to list the most significant groupings into which objects "naturally" fall. By correctly categorizing an object, Aristotle thought, we can thereby know it fully. The categories Aristotle discussed are ten in number: substance, quantity, quality, relation, place, time, position, state, action, and affection. Perhaps it is best to let Aristotle himself explain what he meant by each of these:

...examples of substance are "man" or "the horse," of quantity such terms as "two cubits long" or "three cubits long," of quality such attributes as "white," "grammatical." "Double," "half," "greater" fall under the category of relation; "in the market," "in the Lyceum," under that of place; "yesterday," "last year," under that of time. "Lying," "sitting," are terms indicating position;3 "shod," "armed," state; "to lance," "to cauterize," action; "to be lanced," "to be cauterized," affection [as in "to be affected by something"]. (Categories, 1b-2a)4

The first four of these were, by far, considered the most important, meriting a chapter each. The remaining six, meanwhile, were dealt with together in a single chapter.

Substance, in particular, was considered crucial, for it seemed to be the subject of which all other properties are attributed. There might be substance without color, for instance, but there cannot be color without a substance to posses it. A substance (ousia, in Greek) for Aristotle was not a mass "stuff" -- like water or stone or bronze -- like it is for us, but appears to have paradigmatically referred to medium-sized objects like men and horses and trees (see Barnes, 1995, for further discussion of this point). In the Metaphysics, Aristotle explored the possibilities here by bidding the reader to imagine stripping a substance of its attributes one by one: its state and position and time, its relations to other things, its color and other qualities. What would be left? His answer was as follows:

...when everything else is stripped off, evidently nothing remains. For while the rest [of the attributes] are active or passive processes or capacities of bodies, length, breadth, and depth are quantities. They are not substances, for quantity is not a substance; rather substance is that to which first of all these belong. But when length, breadth, and depth are taken away, we see nothing left, unless there is something made definite by these. So to those who look at it this way, matter [hulę] alone must seem to be substance.

By matter [hulę] I mean that which is not in itself said to be a given anything, nor of a given quantity, nor characterized by any of the other categories which define being. (Metaphysics, 1029a, italics added)5

Aristotle was after the basic stuff that underlies all other properties. This was a problem that he inherited from Plato, who struggled with the same issue, it will be recalled in the Timaeus. Aristotle gave "man" and "the horse" as examples of substances in the Categories. They can be big or small (quantity), brown or white (quality), and so forth. But what happens when you take away even the "manness" of the man, or the "horseness" of the horse? You are left with a pure substrate; something that has no properties at all, but that has the potential to be anything, depending on what properties you now give it. Aristotle called this pure substrate hulę, a Greek word originally meaning "wood," but in Aristotle's time coming to mean the basic matter of the cosmos. Aristotle's basic definition of matter was astoundingly straightforward and lucid: matter is simply that which can be moved.

Given that we can now imagine (if not actually have) prime matter, how is it that we can turn it into an actual object? By adding to it the various properties representative of the categories listed above. Collectively, these properties were called by Aristotle eidos or morphę, usually translated as "form." If I want some matter to become a statue of Pericles, for instance, I must in some sense combine it with the form of Pericles. If I want it to be a car, I must combine it with the form of a car. Somewhat more obscurely (and this is why "form" is not a perfect translation), if I want it to be red, I must give it the "form" of redness. In general, then, matter is closely connected to potential or power; the potential or power to become some particular sort of thing. Only by giving it form can it be made actual (i.e., made into an actual object of a particular kind). This portion of Aristotle's metaphysics is called hylomorphism, because it is the claim that all objects are a combination of matter (hulę6) and form (morphę, though Aristotle himself usually used the term eidos).

Aristotle believed that his hylomorphic theory answered the problem of change posed by Parmenides. Recall that Parmenides believed change to be impossible because it implies that something passes into nothing, and something else passes out of nothing. Since the "nothing" was thought not to exist, Parmenides concluded that all change is impossible. Aristotle's reply is that the basic matter remains the same underneath all change. Only new forms are put in the place of old forms. For example, a block of stone becomes a statue of Pericles because the block-form is removed and replaced with a Pericles-form by the sculptor.

Just as Aristotle concerned himself with matter stripped of all its forms so he concerned himself with the question of pure form -- form that has not yet been combined with matter. If pure matter is pure potentiality, he reasoned, then pure form must be pure actuality. Also, since matter is defined as that which can be moved, then pure form must be immovable. Further, since movement is a kind of form (viz., a combination of the categories of place and time), pure form must be the source of movement. It must, in Aristotle's words, be an "Unmoved Mover." This sounded to Aristotle's ears very much like a definition of God: pure actuality that turns formless matter into actual objects but never moves or changes itself.

In spite of the theological implications, it is important to understand that Aristotle's "form" is not the same as Plato's "Forms." For Plato, the Forms were substances in their own right. All individuals of a particular kind (e.g., horses) must participate in the Form (e.g., Horse) in order to be what they are. The Form is primary. The individual is secondary; a mere "pale reflection," as he said, of the Form. For Aristotle, things are almost exactly the reverse. The individuals are "primary," he says in the Categories (2a-b). The groups to which they belong are "secondary"; this is because they depend on the existence of the individuals. That is, the classes themselves have no independent reality of their own, only that of their individual members. If there were no horses, for instance, there would be no species called "horse." The individuals, however, contrary to Plato, are not similarly dependent for their existences upon the groups to which they belong.

We have looked at some aspects of Aristotle's logic and metaphysics. Now we have only to look at his physics -- his famous theory of cause, in particular -- before we go on to a consideration of his psychological thought. The nature of causation was a central issue of physics for Aristotle. He argued that there are four sorts of cause. The word he actually used was aitia, a term that is broader in its meaning than the modern English word "cause." An aitia can be a reason or motive or explanation, as well as a cause (as we understand that term). Thus, a more felicitous rendering of Aristotle's claim might be that he thought there are four kinds of explanation, rather than cause, but we will use the traditional translation here. The four types of cause Aristotle identified were the material, formal, efficient, and final. Material and formal we have already seen. The material cause of a thing is the matter of which it is made; e.g., the material cause of a of statue of Pericles is the stone of which it is made. Another way of putting this is that the material answer to the question, "Why is it a statue of Pericles?" is that it is made of stone. The formal cause of a thing is its form or organization; i.e., the formal answer to the question, "Why is it a statue of Pericles?" is that it is shaped like Pericles. Efficient cause is somewhat similar, though not identical, to the modern concept of cause; it is the initiator of motion or change. Thus, the efficient cause of the statue of Pericles would be the sculptor's work with the hammer and chisel. Finally we come to final cause, which is the end or goal toward which a thing is aimed; its purpose or function. This idea, often called "teleology," has drawn to Aristotle much criticism from modern philosophers and scientists. "How can a future state cause anything?", so the argument usually goes. To return to our statue of Pericles, the answer seems relatively straightforward: the statue is being carved in order to glorify the memory of Pericles. That is, the final cause is the goal in the mind of the sculptor, or at least of the person who commissioned the statue. In the case of animal or plant growth, things are a little more dicey. Is it fair to say that becoming a frog is somehow the cause of the tadpole's developing in the way that it does? Does "to become an oak tree" explain the growth of an acorn? To Aristotle it was obvious that this must somehow be the case. After all, a tadpole never becomes an oak tree, nor an acorn a frog. Finally we come to the problem of final cause in the physical sciences. Can a rock or a planet ever be said to do something for the sake of some future goal? Certainly we would say not. Toulmin and Goodfield (1962), however, make a very interesting point about a key difference between the scientific aims of Aristotle and those of modern scientists.

Why did Aristotle not draw our modern conclusion -- namely, that the chemical processes going on inside animals are essentially similar to those in the inorganic world? This answer is: he did --but, having done so, he interpreted the conclusion in the reverse direction to ours. Instead of treating inorganic reactions as the fundamental model or "paradigm", and going on to explain physiological processes in terms of these, he took organic development as his paradigm for explaining all material change; any parallels between organic and inorganic processes only served to reinforce his initial commitment to the physiological model. (p. 94, original italics)

That he did so is hardly surprising when it is recalled that his primary scientific research area was biology. Moreover, as we have noted repeatedly in the previous two chapters, an "organismic" view of the cosmos was as unexceptionable to the ancient Greeks as the mechanistic one is for us. To overturn this long-standing assumption, assuming that Aristotle could even have seen reason to, would have required far more argumentation, and incurred far more criticism, than to work within the boundaries of what was then considered to be established fact.