Philosophy

4

LECTURE: Aristotle and the immateriality of the intellect

The intellect, as Aristotle and Aquinas understand it, is that faculty or capacity by which we form abstract concepts, put them together into complete thoughts or propositions, and reason logically from one proposition to another. As we’ve seen, they take the intellect to differ in kind and not merely degree from sensation and imagination. We want now to look at some of the reasons why, in the Aristotelian tradition, the intellect is also regarded as immaterial – that is to say, as irreducible to brain activity or any other material aspect of human nature.

Form without matter

Here’s an argument Aristotle gives for that conclusion. What happens when the intellect comes to understand something? For Aristotle, the answer is that it takes on the form of that thing. For example, when the intellect understands what it is for something to be a triangle, the same form or pattern that makes something a triangle comes to exist in the intellect, and makes what it is doing a thought about a triangle. You think: “That is a closed plane figure with three straight sides.” The form or pattern being a closed plane figure with three straight sides is both in the ink marks that make up some particular triangle (thus making it a triangle) and in the content of your thought (again, thus making it a thought about the triangle).

Now, when a form or pattern comes to exist in a material thing, then that thing becomes the kind of thing that the form or pattern defines. For example, when the form or pattern of being a triangle enters into a certain quantity of ink (as it does when you draw a triangle on a piece of paper), then that quantity of ink becomes a triangle. In that case, though, if the intellect were a material thing, then when it takes on the form of a thing (as it does when it understands it), then it would become the kind of thing that the form defines. For example, when your intellect takes on the form or pattern of a triangle (as it does when it understands triangles), then it would itself become a triangle.

But of course, that’s absurd: The intellect does not become a triangle when it thinks about triangles, or a dog when it thinks about dogs, or what have you. Therefore, Aristotle concludes, the intellect must not be a material thing. For it can do what matter cannot do: namely, take on the forms or patterns of things without becoming those things.

This, for Aristotle, is essentially what it is to have an intellect – it is to have the ability to take on the form of a thing without becoming that thing, to strip form from the matter in which it is embedded and consider it in abstraction or isolation from matter. And only what is immaterial can do that. If the intellect were a material thing, then when it takes on the form or pattern of triangularity (as it does when it thinks about triangularity), it would just become one particular triangle among others, rather than thinking about triangularity as such, in the abstract.

Here, in outline, is this first argument:

1. When the intellect grasps the nature or essence of a thing, the same form that exists in the thing known comes to exist in the intellect.

2. But for a form to come to exist in a material thing is for that thing to become the kind of thing the form is a form of.

3. So if the intellect were material, then when it grasps the nature of a thing, it would become the kind of thing whose nature it grasps.

4. But this is absurd; the intellect does not become a triangle when it grasps the nature of triangles, or a dog when it grasps the nature of dogs.

5. So the intellect is not material.

The meaning of a physical representation

Here’s a second argument, which later thinkers in the Aristotelian tradition give. Its basic idea is that there is a deep mismatch between what is going on in our intellects when we understand a concept, and what is going on in the brain (or in any other physical organ, for that matter). And this mismatch makes it impossible for thinking to be a purely physical activity.

Here’s one way to understand the mismatch. If a thought was something physical, then it would have to be something like a physical representation or symbol encoded in the brain – embodied as a series of neurons firing, say. And the problem with that is this. A thought can have an entirely unambiguous, clear, precise, or exact meaning or content. However, any physical representation or symbol cannot have an entirely unambiguous, clear, precise, or exact meaning or content. Therefore, a thought cannot be identified with some physical representation or symbol encoded in the brain. They are just fundamentally different kinds of thing. A thought is something non-physical or non-material.

Let’s unpack this. What does it mean to say that a physical representation or symbol cannot have an entirely unambiguous, clear, precise, or exact meaning or content? Consider a specific example of a physical representation – such as (if you’ll pardon a triangle example again!) the following:

Now, what exactly does this representation represent? Does it represent triangles in general? Or does it represent only triangles with black outlines, specifically? Does it represent a pyramid? Or a triangular UFO? Or a dinner bell? Or a billiards rack? Or an upside down “Yield” sign? Or a triangular hat?

Notice that there is nothing in the physical properties of the symbol that can tell you – nothing in the exact shape, color, size, or what have you. Of course, we could simply stipulate that it represents a pyramid (say), or a UFO, or whatever. But until we do that, there is nothing about the object itself, considered just in terms of its physical properties, that can tell us. That is to say, the symbol or representation is, by itself, ambiguous or indeterminate or inexact in its meaning or content, in what it represents. And notice that that remains true no matter what we add to the symbol. For example, suppose we added the letters “UFO” to it, as follows:

UFO

Have we now removed all ambiguity? Not at all. This could represent a UFO. But it could also represent instead a pyramid with the letters “UFO” on the side, or a hat with those letters on it, or any number of other things. No matter what physical marks or parts we add to it, there will always be alternative meanings it could have. There is nothing in any set of physical properties that can, by themselves, determine what the meaning or content of a physical representation is.

Notice that this is even more clearly true of linguistic symbols – words, whether written, spoken, typed into a computer and saved on a flash drive, or whatever. A word like “triangle” represents triangles, but only as a matter of convention or custom. There is nothing in the physical properties of the written string of shapes T-R-I-A-N-G-L-E that gives them any meaning. Nor is there anything in the string of sounds that we make when we say the word that gives them any meaning. The meaning is imposed on these physical features from outside – by us as thinking things, as entities with intellects or minds.

The meaning of a thought

Now, notice that the meaning of a thought is very different. Suppose I ask you what you are thinking about. You answer: “Triangles.” I respond: “Are you sure? Maybe what you are really thinking about is UFOs, or dinner bells, or pyramids!” Your reply, no doubt, would be: “What are you talking about? I’m thinking about triangles. I just told you! None of those other things even entered my mind until you mentioned them.”

In other words, the content or meaning of your thought is entirely unambiguous, precise, or exact. There is a straightforward fact of the matter about what concept you were entertaining. What you had in mind were triangles, and that’s that.

So, we have this crucial difference between thoughts and physical representations: Thoughts can have an entirely unambiguous and precise meaning, whereas physical representations cannot. This is one of several ways, then, in which there is, on the Aristotelian view, a mismatch between thought on the one hand, and anything material on the other.

Because of this mismatch, the argument concludes that the intellect – the power by which we think – is not a bodily or material power. It cannot be reduced to brain activity. To be sure, the Aristotelian view doesn’t deny that brain activity is part of the story. The Aristotelian view acknowledges that the intellect needs to derive information from the senses and from the imagination (the power to form mental imagery), and these depend on the brain and other bodily organs. That’s why damage to the brain can dramatically impair the intellect’s operation. All the same, the Aristotelian view holds that there must also be more than mere brain activity going on.

Here, in outline, is this second argument:

1. If the intellect were material, then to have a thought would just be to have a physical representation (e.g. encoded in a neuronal firing pattern in the brain).

2. But no physical representation can have a precise, unambiguous, or exact meaning or content.

3. And our thoughts often do have a precise, unambiguous, or exact meaning or content.

4. So to have a thought cannot be merely to have a physical representation.

5. So the intellect is not material.

Next time we’ll see how, in Aquinas’s view, the immateriality of the intellect opens the door to the immortality of the human soul. Meanwhile, here are some optional YouTube videos on our topic:

iAquinas on Proving the Spirituality of the Soul in Saint Thomas:

https://www.youtube.com/watch?v=c6hvJyQ0wbk

Aquinas 101 on Thomistic Epistemology:

https://www.youtube.com/watch?v=mmWmHB50DG0