Reading notes for Aristotle's De Anima (Hamlyn)

To his credit, Aristotle doesn’t stop there. He entertains the question “How can something be affected by a perceptual quality (e.g., a smell) without that thing perceiving that quality?” It is a good question, but smell isn’t the clearest example he could have used. He uses later the better case of light and darkness. Light and darkness are visual qualities, yet they can affect plants; does that mean that plants must be able to see? This question is especially poignant because of Aristotle’s emphasis on the sensory medium; since light and darkness don’t directly affect the body, but only the sensory medium (air or water), how can that sensory medium in turn affect, say, a plant unless the plant can see? In other words, if sensing is being affected by a change in a sensory medium, then plants would have to see.

He points out the exception for touch and taste (424b13). What is touched or tasted directly affects a sensory medium, but this sensory medium is the body (the skin or the tongue). So tangible qualities, like hot and cold, cold, can affect plants without the plants being able to sense them. When a heated iron touches a plant it affects the plant by the matter of the iron burning the matter of the plant; form is not sufficient, so this can’t be a case of perception.

But this doesn’t allow us to explain the case of light and darkness affecting the plant, for there the matter of the source of light need not touch the matter of the plant.

Aristotle doesn’t resolve this, and the end of the chapter “looks like a number of lecturer’s questions thrown out seriatim by way of challenge” (Hamlyn, p.115). But he does suggest in one of his questions that there is something more to sensing than being affected by a perceptual quality. This is a weighty issue, for it involves such questions as “Where in the processing of the visual system does the seeing happen? If in the brain, then in a particular neuron?” and “What exactly happens in the brain of one who understands an explanation of the Pythagorean theorem that doesn’t happen in the brain of one who doesn’t understand but who nonetheless perceives the words and pictures?” This last goes beyond perception into cognition; the plant is to the perceiver as the mere perceiver is to the knower. This takes us to Book III, where Aristotle takes up the thinking psyche.

Book III

Chapter 1

This chapter argues that there can be only five faculties of special sense, and one common sense.

424b22‑425a13

Aristotle is here giving an argument that there cannot be more than the five senses (unless there exists a fifth element (in addition to earth, air, fire, and water), and this fifth element is such that it can serve as a sensory medium). The argument is not clearly laid out, and some important premises are suppressed, but the upshot seems as follows.

Sensation is either through a medium or by direct contact (or, he should have added, given the case of touch, by both). As for direct contact, our sense of touch perceives all the possible tangible qualities. So if there is a sixth sense, it must operate via some medium without direct contact. But no sense could operate via fire or via earth as media, for fire and earth equally belong or don’t belong to all sense organs. (Aristotle seems to think that the option which holds true is that fire and earth all equally belong; for each sense organ must be a warm bodily thing.) So the only elements which can serve as sensory media are air and water. (Air and water conduct color, sound, and smell.) So there can be a different sensory modality only if there is a different sensory medium than those already reserved for sight, hearing, and smell. Therefore, there is a sixth sense only if there is some fifth element (and this element would have to have medial capacity).

Suggestive as it is, there is more than one problem with the argument. See if you can articulate some of these.

For example, which step in the argument would stumble on bats’ use of sonar, or on the ability of some fishes to perceive minute disturbances in the electromagnetic field (like the thrashing about of potential prey hundreds of meters away at night)?

425a14‑29

Without claiming to have given an exhaustive inventory, Aristotle throughout the De Anima has described the special objects of sensation as such qualities as light, dark, color (vision), pitch, volume, smoothness, roughness (sound), sweet, bitter, pungent, sharp, oily, (smells), sweet, bitter, oily, salty, pungent, rough, astringent, sharp (taste), and hot, cold, dry, wet, rough, smooth (touch). These qualities are not incidental to their sensory modality, Aristotle claims, meaning that each is essential to its modality; by this he means that each such quality is distinctive to just one modality, and is not shared by any two senses. Hence he calls them special objects.

How then do we sense such qualities as movement, rest, figure, magnitude, number, and unity? (Recall these as the common objects of sensation from 418a16‑19.)

Aristotle’s answer here goes quite a bit further than his discussion in II.6. He here says that there is not a (sixth) special sense which perceives such qualities as movement. His argument is that if there were a sixth special sense for movement, then we would “see” movement only in loosely speaking way in which we “see” the sweetness of the sugar; we see the whiteness, and the white thing happens to be sweet. Aristotle thinks that we see movement in not as extended a way as we see sweetness, but not in as proper a way as we see color.

He pursues this middle way by postulating the existence of a common sense (later called a sensus communis, or the common sensorium), for which the perception of movement is essential, and so more than incidental. So the perception of movement is incidental to the five special senses, but essential to the common sense. This common sense is common in that the quality of movement can be funneled to it via more than one special sense (for example, via sight, via touch, via hearing, and perhaps via smell).

Chapter 2

This chapter concerns by which faculty we perceive that we perceive and by which we perceive that different special objects belong to different sensory faculties (for example that sweet differs from white), and in what way an object of perception is the same as (and so does not outlast) an act of perceiving.

425b12-25

If perception is a form of noticing, then to notice that we are perceiving is to notice (second‑order) that we are noticing (first‑order). Aristotle asks whether the same faculty (for example, vision) is responsible for both orders of such noticing.

Aristotle first considers that it’s the same faculty (in the passage “But in that case...will be the one for itself”). He poses a difficulty for this option. Put the difficulty into your own words.

He then (b15-16) considers the second option—that the faculty that perceives is different from the faculty that notices that we perceive—and poses a difficulty for it. What is the difficulty?

From b17‑25, Aristotle seems to endorse the solution that it is by sight that we see that we see (so it’s the same faculty, the first option above), but that the regress is avoided by noting that “to perceive by sight is not a single thing,” citing the (irrelevant) example of how perceiving light differs from perceiving darkness.

So Aristotle leaves us with no good solution. It may be evident to the modern mind that what Aristotle needs in order to solve the problem is the notion of self‑awareness, or self‑consciousness. This may be true, but then such notions aren’t without challenges themselves. For example, how can a faculty be aware of itself? That sounds pretty magical. Furthermore, it’s exactly the same form of problem that Aristotle is opening this chapter with, although he’s restricting it to the perceptual realm.

Also note the link between this issue and Plato’s comment at Republic 430e‑431a that the phrase “self‑control” (or “master of oneself”) is laughable, in that it’s ridiculous to speak of the controller and the controlled as one.

425b26‑426a14

Aristotle next argues that because the activity of the object of perception is identical to the activity of the sense (though somehow to each there belongs a different account of what it is to be what it is—the italicized portion being a phrasing throughout Aristotle that is often translated as “the essence”), the object of perception and the sensing “must be in that which is potentially” sensing. So the sound and the hearing are both in the ear. The sound is not in the gull’s cry, or in the air. He seems to hold that there is not a process of perceiving that gives rise to some additional entity, a percept, but rather the perceiving is a percept.

426a15‑26

Aristotle now addresses the very deep issue of what this view (that the perception exists in the perceiver) entails about how perception can link us with the world outside the perceiver. Since the sound is what we hear, and he has just claimed that the sound is in the ear, he seems to be left with the view that whatever we hear is in us, not out there in the world. The implication, then, seems to be that there is no such direct perception/world link; we do not access the world by perception, for the perception, the only thing with which we are directly familiar, is a state of the observer, not a state of the external world (even if it was in some, perhaps indeterminable way, caused by the external world). This was the view of such thinkers as the atomist Democritus and the relativist Protagoras.

If the activity of what’s perceived ceases to exist when the activity of perceiving stops (as would apparently have to be the case if the activity of the object of perception = the activity of perceiving), then there would be no objects of perception when they’re not actually being perceived. The sugar wouldn’t be sweet unless it was being tasted, for sweetness would exist only in the taste organ internal to the tongue.

Aristotle thinks that this is in a way right and in a way wrong. Be able to explain his position.

426b8‑427a14

Aristotle here takes up the interesting question of how we perceive that, say, white differs from sweet. It can’t be vision, for vision doesn’t receive sweet. And it can’t be taste, for taste is blind to white.

This is a twist on the question with which he had opened this chapter. The difference is that Aristotle’s answer there was clear and irrelevant; his answer here is not even clear. For example, (i) in what sense is a point divisible into two, (ii) how is this analogous to white and sweet, (iii) why does Aristotle include both perception and cognition in this discussion, yet insist that the discrimination between white and sweet “must indeed be by perception; for they are objects of perception,” and (iv) is “[t]hat which judges” (of 427a11) a perceptual faculty?

For what it’s worth, Plato (at Theaetetus 185a‑186e) uses the argument that no sensory faculty can tell that sound and color are two to conclude that not all knowledge is perception (“Then knowledge is to be found not in the experiences but in the process of reasoning about them”). Plato maintains that the psyche uses the sensory faculties, and so can think about them, making generalizations and discriminations. Aristotle cannot agree with this, for he doesn’t think that the psyche is one thing and the sensory faculties another; he thinks sensation is part of (some organisms’) psyche.

Chapter 3

Aristotle here discusses what imagination is, and how it differs from perception, belief, and knowledge. This serves as a bridge between his discussions of perception and of thinking. After reading this chapter, read Shields’s subsection about imagination, pages 173-175.

427b6‑15

Aristotle gives two differences between perceiving and thinking: in domain and in corrigibility. Be able to summarize.

Hamlyn is correct that hupolepsis is difficult to translate. Even his suggestion, “supposal,” is a bit off, as he likely would be the first to admit, for it connotes a tentative entertaining of an idea. “Belief” would a better translation, if it weren’t for Aristotle using a different word for belief at 427b25 for a species of hupolepsis; this passage suggests something like “cognition” as a translation, for cognition is involved in knowledge, belief, understanding, false belief, etc.

427b16‑23

Aristotle gives two (perhaps related) reasons for thinking that forming an image is different from hupolepsis, which here seems to be “believing.” Put them into your own words.

428a5‑15

He adduces four different considerations for why perceiving differs from imaging (which is an appropriately less ambitious word than “imagining”; to image something is for you to have that thing appear to you): at “Perception is...,” at “Secondly,...,” at “Next,...,” and at “Further,....” What are the four? Laurels to those getting the fourth (in a way that makes it genuinely different from the rest).

It’s not clear why, but the final sentence repeats the first of the four points.

428a16‑23

He gives a reason for imaging not being knowledge, and two reasons for it not being belief (the word being doxa, similar to hupolepsis). List them.

428a24‑b9

He gives an argument for imaging not being a combination of belief and perception. The second half (b4‑9) of the paragraph is difficult, but makes sense. Can you give a less difficult version?

429a1

To Aristotle’s claim that “imagination will be a movement taking place as a result of actual sense‑perception,” compare Hume’s comment from the opening page of A Treatise of Human Nature (1739): “Those perceptions, which enter with the most force and violence, we may name impressions; and under this name I comprehend all out sensations, passions and emotions, as they make their first appearance in the soul. By ideas I mean the faint images of these in thinking and reasoning....” Hume thinks that imaginings and thoughts differ from perceptions and feelings only in that the latter two have a more forceful movement to them.

Although Aristotle is not a Humean, Hume could find much to love in this sentence.

Chapter 4

Now we get squarely to Aristotle’s views on the nature of the thinking faculty (intellect, nous).

429a13‑17

When he says that thinking requires that the intellect be capable of receiving the form of the object of thought, compare the claim about perception at the opening of II.12.

429a18‑28

This passage is not only crucial for Aristotle’s account of the psyche, but the point it makes is hugely influential in the history of theorizing about the mind, its relation to the brain, and its ability to attain knowledge.

Aristotle holds that because everything can come to be known by the cognitive psyche and nothing in the cosmos need remain locked away from us, the intellect must have no nature. It is pure potentiality. For if the intellect had an actual nature, a form of its own, that nature would interrupt the ability of the intellect to receive the forms of some objects. The slate has to be blank (actually blank, though potentially full; cf. 430a1) in order for everything to be legibly writable on it.

It won’t be until Kant’s Critique of Pure Reason (A edition1781; B edition 1787) that someone proposes in any detail that the mind is hard‑wired to think with certain categories (like space, time, causality, substance), with the consequence that anything not conforming to those categories couldn’t be an object of thought for us. Aristotle is more optimistic about the ability of the intellect to know everything in principle.

But that’s not all. Aristotle draws out the implication that if the intellect is to be character‑less so as to be able to take on the character of anything it thinks about, then it cannot “be mixed with the body.” This is reminiscent of 413b24‑31, where he had said that the intellect alone is separable (from the body? from the organism, including the rest of the psyche?).

Despite this precedent, this poses no small problem for Aristotle’s general account of the psyche in II.1: “The psyche must, then, be substance qua form of a natural body which has life potentially...The psyche, therefore, will be the actuality of a body of this kind.” If the psyche is form and actuality, then how can the intellect (part of the psyche, after all) be form‑less and pure potentiality?

Second, even if Aristotle adjusts his general account of what a psyche is, then, given his association of matter with potentiality and form with actuality (412a9), it stands to reason that if the intellect is without form, it’s without actuality. But then if it’s potentiality, wouldn’t it have to be material?

Third, Aristotle believes that even matter has a form, though a lower level form than that of which the matter is matter. For example, a lump of bronze has the form of being a certain ratio of the four elements, even before the sculptor induces the higher level form of sphericality onto the lump. Since matter has some form, this limits the potential it has. Bronze could never become food, for instance. And the element of water could never become fire. But even if Aristotle responds to the second point above with the claim that the intellect is purer potentiality than anything material could ever be, wouldn’t it follow that when the intellect isn’t thinking, it vanishes into the void (since it has no nature of its own)? To call this counter‑intuitive would be too gentle.

429a29‑b9

Aristotle notes two ways in which perception differs from thought, and they both involve ways in which perception but not thought is dependent on the physical world. (1) Only thought isn’t worsened by having an intense object. (2) The intellect can think by itself, but the perceptual faculties require an external object. (And lest you object that it’s possible to imagine an object that’s not present, remember that Aristotle has already given not one, but four reasons for holding that imaging is distinct from perception [428a5‑15].)

429b22‑430a9

Aristotle poses and responds to two questions about his view of what the intellect is. (1) If x can act on y only in virtue of some similarity between them (for example, rain can act on a seed only if they are both material objects and only if they exist at the same time and place), then how can actual objects of thought act on a completely non‑actual intellect? (2) Can the intellect think about itself? (Given what Aristotle has said in this chapter, why might this second question be a special challenge for him?)

He provides an answer to each in the second half of the passage. What are his answers?

Chapter 5

Shields has a short passage about Aristotle’s account of mind, pages 175-176.

This chapter is where Aristotle introduces the distinction between the passive intellect and the active (or producing) intellect. It represents a fast break from the previous chapter’s analogy between perception and thought (cf. 429a13‑17). In fact, it is surprising that the account of thinking in III.4 is so bereft of any hint of there being two intellects, or, at the very least, two aspects of the intellect.

An example of this puzzlement is that where before he had said that the intellect has no nature and is only potential (429a21), he now commits himself to saying that there is an intellect which is pure activity, and so is pure form and has a full nature (activity, form, and nature all being linked in Aristotle’s metaphysics). This new wrinkle can’t simply be appended onto III.4, for it’s incompatible with much of III.4.

Any ideas?

Chapters 6 and 7

Since these chapters raise issues of rather less relevance to the theme of the rest of the work, since they are somewhat scattered in content, and given the number of corruptions in the text, it is tempting to think that these either were interpolations from another author or, if by Aristotle, were not intended to be part of the rest of the work.

Skimming these chapters suffices, except read the first two and last one paragraphs of chapter 7.

Chapter 8

Aristotle sums up his views of what happens to the psyche when it engages in perception and cognition. In fact, the second two paragraphs of this chapter constitute an explanation of the first paragraph. Consider the following quiz: given what Aristotle says in the rest of the chapter, how are we to explain exactly what he means by the two occurrences of “in a way” in the opening paragraph of chapter 8? The degree to which you can answer this is the degree to which you understand the De Anima.

Chapter 9

Chapters 9-11 concern the role of the psyche in the production of movement. Only bodily things would seem able to move bodily muscle and bones. Yet since only living (that is, empsychied) things generate movement, there must be some role for the psyche to play in movement.

This chapter lays out fairly clearly Aristotle’s reasons for why movement cannot be the responsibility of the faculties of generation and nutrition, or of perception, or of the intellect.

Chapter 10

Aristotle’s naturalism requires him to locate the source of movement in some ability that even animals have, and this inclines him to desire. But he notes that although desire (or as he puts it, the object of desire) is primary, there are cases in which desires can conflict, and cases in which practical intellect can veto a desire.

Socrates would say that these latter cases show that it is thinking that is the source of movement, since we move towards something when we think it’s good for us.

Aristotle wants to retain the primacy of desire, however. It is difficult to see how, however, given that he shows that he recognizes cases of conflicts among desires and between a desire and practical intellect. One way to make Aristotle’s position consistent here—although speculative because there is no direct evidence for it in the passage—is to interpret him as holding that desire is the source of movement, but practical intellect holds veto power over desire. (This suggestion does not fit well, however, with Aristotle’s claim early in the chapter at 433a12 that “Both of these, therefore, can produce movement in respect of place, intellect and desire.” But then perhaps the rest of the chapter should be taken to refine, and even revise, its opening lines.)

In the opening paragraph of this chapter, Aristotle seems to be allowing non-human animals to have a kind of intellect, namely, practical intellect (by which he means thinking concerning action, as opposed to contemplating, say, the Pythagorean theorem). He is allowing in, but in only a qualified way, for it is conditional upon his “if we set down the imagination as a kind of thought.” This does reveal the oft-noted uneasy place Aristotle gives to imagination. He sometimes treats it as if it is between perception and thought, but then at other times as present in both.

His suggestion in this chapter that imagination might be a kind of thought certainly has something to recommend it, even if it does not fit well with some other things Aristotle has to say. A cat can presumably form an image of the mouse it has seen go under the molding, and it is not overly charitable to credit the waiting cat with thinking about the mouse. If you block the cat’s line of vision of the place where the mouse disappeared, the cat will move to regain a line of sight.

433b13-20

Clarity on the four-fold distinction (three things, and then one of them is twofold) is provided by Hamlyn in his note.

Chapter 11

A difficult little chapter, this.

433b31-a4

Aristotle considers how movement occurs in animals that have no sense other than touch. He is willing to grant that they have wants, and so the faculty of desire, but is less willing to think of them as having imagination.

He is appropriately tentative about all this. Even today, those of us who would grant that since, say, a starfish can feel for its food, it likely can feel pain, in order to move away from noxious stimuli, might give greater pause to thinking that the starfish can form images.

Yet given the primacy he had placed in the previous chapter on desire as the source of movement, one wonders why he does not simply say that wants are enough. Any animal that has wants has the ability to start movement.

434a10-15

Although not coming out and explicitly claiming it, Aristotle here interestingly suggests that some non-human animals have beliefs—just not beliefs arrived at through inference. Presumably he is thinking that they could have beliefs based on perception, like the belief that the mouse is behind the wall.

Chapter 12

This chapter summarizes Aristotle’s views about which faculties of the psyche presuppose which other faculties.

434b9-17

Aristotle argues for the primacy of touch, such that any living thing that has perception, must have touch, even if it lacks all other senses. A problem with Aristotle’s reasoning emerges when one considers, although granting his claim “every body is tangible,” it is no less true that every body is visible.

435a5-10

As Hamlyn points out, this passage confirms that Aristotle holds the common view of his day that vision proceeds by something going out from the eye to the object seen. I find Aristotle’s paragraph intriguing, but obscure.

This view of vision, by the way, strikes us as naïve, but then note how easily we fall into a version of it when we see depictions of superheroes with x-ray vision. Beams of x-rays are shown emanating from Superman’s eyes, instead of his eyes simply receiving light in the x-ray portion of the spectrum. This latter would not at all make for a dramatic drawing.

Chapter 13

Frustrating expectations of a conclusion to the work, Aristotle, or whoever wrote this chapter, continues from the previous chapter some comments about the uniqueness of touch among the senses. Touch is for survival, whereas the other senses are for well-being.

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Reading notes for Aristotle's De Anima Michael Taber

Reading notes for Aristotle's De Anima
Michael Taber