Philosophy

5

LECTURE: The powers of the rational soul

The rational or human soul

Recall from last time that, for Aristotle, the soul is the substantial form of a living body. And the human or rational soul, specifically – the kind we have – is the kind of form that gives the thing that has it the powers of the vegetative and animal souls, together with the distinctively human powers of intellect and will. In particular, the rational or human soul underlies the following powers or capacities:

1. Nutrition

2. Growth Vegetative powers

3. Reproduction

4. Sensation HUMAN SOUL

5. Appetite Sensory powers

6. Locomotion

7. Intellect Rational powers

8. Will

For Aristotle and other Aristotelians (like Aquinas), the human or rational soul differs in kind and not merely in degree from the animal or sensory soul. The reason is that the intellect differs in kind and not merely in degree from sensation. And that entails that the will, in turn (also known as rational appetite), differs in kind and not merely in degree from the appetites or inner impulses which non-human animals possess. To be sure, we do possess sensation and appetite as well. We are, for Aristotle and Aquinas, animals of a certain kind. But we are not mere animals, because of the difference of intellect and will from what non-human animals are capable of.

Imagination

Now, a non-human animal may have powers of imagination that enable it to react to more than just what it immediately perceives. “Imagination” in this sense is the capacity to form mental images, sometimes also called “phantasms” (an old-fashioned word related to the word “fantasy”). A mental image is essentially a faint copy of what you experience when you are actually perceiving something. For example, if you look directly at your mom, you’ll have a vivid visual experience of seeing the shape of her face, the color of her clothing, and so on. Later on, you might call to mind what she looked like, but the mental image you form will be analogous to a faded photograph, lacking the vividness and realism of the visual sensory experience.

Sensation Imagination

I’ve been giving a visual example, but there are mental images associated with all five senses. For example, you might call to mind what mom’s voice sounds like, and that would be a mental image of an auditory kind – a kind of faint copy of what you experienced when you heard her voice. You can also form mental images from things you’ve experienced via the other senses. For example, you can imagine what pizza tastes like, what a rose smells like, or what ice feels like.

Non-human animals can do this too, which is why their behavior can be fairly complex and flexible. For example, a dog might feel excitement after something calls to its mind an image of something it has enjoyed in the past (e.g. if you yell “Fetch!”). Imagination – the capacity to form mental images – is a kind of extension of the power of sensation. Naturally, we share this capacity for mental imagery with non-human animals, just as we share the power of sensation with them.

Intellect

Still, for Aristotle, Aquinas, and many other philosophers, that is simply not the same thing as having an intellect. Recall from last time that intellect involves three basic capacities:

1. The capacity to grasp abstract ideas or concepts (like the concept man or mortal)

2. The capacity to put concepts together into complete thoughts or propositions (like the proposition that all men are mortal)

3. The capacity for logical reasoning from one proposition to another (as when we reason from the propositions that all men are mortal and Socrates is a man to the conclusion that Socrates is mortal)

The most basic of these – the one the others are built on – is the capacity to form concepts. And concepts are simply not the same thing as mental images. For Aristotle, it is because non-human animals don’t have concepts that they don’t do things like logical reasoning and what builds on logical reasoning (philosophy, science, etc.).

The difference between the intellect and the imagination, then, ultimately derives from the difference between concepts and mental images. So let’s focus on that and see exactly what the difference is.

Concepts versus mental images

It is easy to make the mistake of supposing that to have a concept or idea of something is to have a little picture or image in the mind. You might suppose, for example, that your having the idea of a triangle or a man involves having a little picture of a triangle or a man in your mind – again, that it involves having mental imagery.

Hold on, I’m picking up an image!

However, there are at least three reasons why a concept cannot be the same thing as a mental image of any kind. We might summarize the differences as follows:

Mental images (or “phantasms”) Concepts (or “ideas”)_______

1. Concrete and individual 1. Abstract and universal

2. Vague and indistinct when the 2. Clear and distinct however

subject matter is complex or complex or detailed the

detailed subject matter

3. Cannot form images of some 3. Can nevertheless form

things concepts of those things

Let’s unpack each of these points:

1. Concrete versus abstract: First, note that mental images are always individual or particular rather than abstract or general. For example, suppose you form a mental image of a triangle. It is inevitably going to be a mental image of a blue triangle or a green one, an obtuse triangle or an acute one, a large triangle or a small one, and so on. It is always going to have certain specific features that not all triangles have, so that it does not strictly speaking stand for all of them. By contrast, the idea or concept of a triangle is completely general or abstract, and does apply to all triangles, whether blue or green, acute or obtuse, large or small. So, the concept is not the same thing as a mental image or picture.

Or consider the concept of living thing. This clearly cannot be the same thing as a mental image. If you try to form a mental picture of a living thing, it is inevitably going to be an image of some specific kind of living thing – a bird, a frog, a whale, a tree, a worm, an amoeba, or whatever. It isn’t going to apply to all living things, but only to some. But the concept or idea of living thing does apply to all living things without exception. So, the concept is not the same thing as a mental picture. In the same way, the concept of man is not the same thing as a little mental image of a man, the concept of tree is not the same thing as a little picture or image of a tree, and so on.

2. Vague versus clear and distinct: Second, note that with some things, we have a clear concept, but only a vague mental image. For example, if I ask you to form an image of 500 trees and then an image of 600 trees, the mental images look pretty much the same – just a vague picture of a bunch of trees. But the concept or idea of 500 trees is clearly and distinctly different from the concept or idea of 600 trees. So, since the concepts are different but the images are not, a concept is not the same thing as a mental image.

An image but not a concept

Here’s another example famously used by Descartes (who, though he disagrees with Aristotle and Aquinas on some important issues, agrees with them about the difference between concepts and mental images). Consider the idea of a chiliagon, which is a 1,000-sided geometrical figure, and the idea of a myriagon, which is a 10,000-sided geometrical figure. Suppose you are asked to imagine – to form a mental picture – of a chiliagon; and then to form a mental image of a myriagon; and then a mental image of a 1,200-sided figure; and then a mental image of a circle. The mental images are bound to look more or less the same. You cannot really imagine – that is, form a mental picture – of the difference. However, you can very easily understand the difference, just by hearing the definitions of these terms. The concepts or ideas are clearly different even though the images are not. So, again, a concept is not the same thing as a mental image or little picture in the mind.

3. We have concepts of things we can’t imagine: Think of pure abstractions like the idea of law or the concept of logic. These aren’t physical objects that you can literally see or touch, and thus you can’t form an image or mental picture of them. Of course, you can form a mental image of the word “law,” but that is not the same thing as law itself. For example, they had law as an institution in ancient Greece and ancient China, but they didn’t have the English word “law.” You can form a mental image of a lawyer in a business suit or of a modern courtroom, but those things too are not law as an institution (since, again, they had law in ancient Greece and ancient China, even though they didn’t have modern business suits or courtrooms). So, though we have the concept of law, this doesn’t involve having some mental picture or image of law. And so on for other extremely abstract concepts.

The lesson, once again, is that concepts are not the same thing as mental images or mental pictures (even though we also do, of course, bring to mind mental images when we entertain concepts). Strictly speaking, we need to rely on words rather than images in order to convey concepts. For example, the concept of being a triangle is best conveyed via a definition like “A triangle is a closed plane figure with three straight sides.”

It is our possession of concepts that makes it possible for us to go on to form propositions or compete thoughts, and then in turn to reason logically from one proposition to another – and, beyond that, to develop philosophy, science, art, literature, music, laws, and all the other things that set human beings apart from non-human animals.

But the difference here is even greater than the difference between animals and plants, or between plants and non-living things. For those things are all entirely physical or material. But in Aristotle’s view, the intellect differs from these things in a more radical way, insofar as it is non-material. It is not entirely reducible to brain activity (even if it is partially dependent on it). And for Aquinas, this opens the door to the immortality of the human soul. We’ll see how those arguments go next week.

Meanwhile, here’s another optional YouTube video on our subject:

Aquinas 101 on the Powers of the Soul: A Closer Look:

https://www.youtube.com/watch?v=UnpycBrUB3U