If you go looking for Plato and you find a book with his name on it, open it, and you don’t find Plato. He never speaks in his own voice. In that sense, nobody knows who Plato is. How different with Aristotle. There’s 2500 pages of text which tell us who Aristotle is. He wrote a mass of stuff on every subject you can think of. There is a good deal that is lost, as well. But the texts we have really are a mixed bag. A lot of them read exactly like lecture notes, with lots of curious allusions and things not explained properly. It also seems pretty clear that he kept work in progress files. So we have a collection of finished pieces, notes for lectures, notes for research and so forth. All of those have been lumped together and called a book and it often makes for very hard reading. And very hard translating as well. It is striking how different Aristotle’s work is from Plato’s and how close to what we now understand as academic work. This may not be a recommendation, but it is worth looking more closely.
Even though Aristotle was Plato’s pupil and/or colleague for years, the two contrast in other ways as well. The central theme for Plato’s philosophy is the transcendent Forms. Aristotle has a variety of problems with the idea, but the third man argument is the most famous of these and it is at the centre of Aristotle’s criticism. In fact, Plato does know of the argument and considers it very carefully. Whether his response is adequate or not is another issue; presumably Aristotle thought it was not. In many ways this is a very simple argument, but people seem to have trouble getting hold of it.
Among other things, the theory of Forms is meant to explain is how it is, for example, that Jeff Mason and I are both human beings. The theory of Forms sets out to explain this by saying that we have something in common. We both resemble the form of humanity. We are two distinct things, but we are linked because we both resemble the for of humanity, which is a third thing. Now, if you explain the resemblance between Jeff and me in a particular way, you must apply that explanation to every other question of the same kind. So, we know there is a resemblance between Jeff and me and that resemblance holds because we both resemble the Form of humanity.
So I can ask what the resemblance is between Jeff and the Form of humanity. We have to explain that by positing another Form, which ties together Jeff and the Form of humanity. And then, of course, if you ask about the resemblance between me and the Form of humanity, you need a third one to tie us together. So now you’ve accepted three Forms – the original Form, the first derivative Form, which ties Jeff and the original Form together, and the second derivative Form, which ties me and the original Form together. So there are not just three, but five things, all of which resemble each other. I can ask the same question again, and we realise that there must be more Forms to link all of these things together. We’re now going up in an infinite regress; the third man argument demonstrates that the theory of Forms implies an infinite regress of Forms. The fundamental point is that the Form of humanity doesn’t explain what it’s supposed to explain.
This problem is due to two things. The Form of humanity is separate from living humans – separation. In addition, the Form of humanity is also human – self-predication. Aristotle does not resolve this by ceasing to use the term ‘form’; as you will see, he needs this term for his own metaphysical theory. He resolves the problem by denying the separation of the forms, and denying self-predication. Hence when Aristotle uses the term ‘forms’, it is a different concept. To mark this, the word is written with a small ‘f’. The Platonic forms, because they’re separate, immortal, eternal and all the rest of it, are always written with a capital ‘F’.
The other point that Aristotle fastens upon is that Plato is inarticulate about what precisely the relationship is between the forms and the particulars, the individuals. Plato uses metaphorical language here; he talks about individuals ‘sharing’ in the forms, or ‘participating’ in the forms. Aristotle complains that this doesn’t explain anything. He thinks he can do better.
So the first issue, illustrated by the third man argument, is about the relationship between the forms and the particulars. The second is the problem of change; this was a difficult, even insoluble problem for early Greek philosophy, and Plato shares in this. For Aristotle, the Forms don’t explain change. Suppose a tree is changed into the beam of a roof. All Plato can do is to announce that this object used to resemble one form and now resembles a different one, but he can’t explain why. On Aristotle’s view, the wood of the tree had one form, it is put through a process, and then it has a different form. It has a different form in two senses; it has a different shape; and it has a different use. We start to move towards a vision of things in the world as having two elements. One of which doesn’t change – he calls that matter. The other which changes, or is changed, he calls that form. ‘Elements’ is not quite the right word here, because neither form nor matter can exist on their own – they can only exist in combination. Aristotle explains change by positing something that underneath the apparent change that remains the same – matter. This gives the continuous identity that underpins what does change – the form.
So we have Aristotle setting out to resolve the problems that are left by the theory of Forms by devising a structure that is partly radically new and partly an adaptation of an existing theory. It’s an adaptation because we’ve still got a concept of form; what’s new is the concept of matter. It may seem commonsensical to us, to say the same chunk of matter is taking on a different form, but that only shows how powerful this approach is and how well it has lasted – though it is true that it did not prove very helpful in physics, and has had to be abandoned there.
Now let me move on to another concept to Aristotle’s metaphysics – substance. This is the Latin translation of Aristotle’s term ‘ousia’ literally ‘being’ or possibly ‘existence’. Aristotle uses a very peculiar linguistic trick when he talks about substance in the effort to identify it. He talks about the word substance and he says ‘a substance is a this’. So you can imagine giving a lecture and making a gesture, pointing to something – ostension. So the emphasis is on the gesture, drawing your attention to what is in front of you, now here – this is what is real. You see how different it is from Plato who gets you to think of a transcendent realm. This is, I think, an extremely important moment in philosophy. This is the moment when philosophers begin to think about how language (or thought) is attached to the world. The ramifications of that problem are endless, especially in the last hundred years or so.
But there’s a catch. Aristotle identifies substance as the first of ten categories. This is a term that Aristotle introduces and it has a continuing history in philosophy. It is difficult to define quickly. Essentially, categories are different kinds of being or existence – properties, relations, etc. Aristotle gives rather different lists in different places. Unfortunately, what Aristotle does is to identify one of the categories as being primary – namely, substance. And so he lays the ground for the idea that the real being of something is a kind of skeleton onto which all the properties and relations that the thing has can be hooked. When things change, you can think of one property or relation being unhooked and something else being hooked on in its place. This is a way of thinking about what it means for something to change colour, and so on. But it isn’t really very helpful. As you think about each thing and start analysing it, everything turns about to be a quality or a property or a relation, and the substance, the thing itself in the middle, disappears. It turns out to be a chimera. As you analyse it, it begins to disappear. In the end, you’re left with the empiricist view that all that exists is collections of properties. Substance turns out to be like the smile of the Cheshire cat.