De Anima III.5: The Agent Intellect as Light—Separable, Impassible, Unmixed, and Act

Orientation #

He opens by recapping what Aristotle “has shown” so far: reason is an undergoing ability lacking any material nature, and its object is the what-it-is of a thing sensed or imagined (prev. lecture). He also recalls “the previous reading”, where the mind was shown not to be a body, and “what we learned long ago” about sensing coming first in our knowledge (verified handout, “An Introduction to the First Road in Our Knowledge”, p. 4). The preceding class treated why understandables do not always understand and the division of speculative philosophy; the following class continues the agent/possible intellect with material from Thomas’s Isaiah prologue.

The class, in order #

1. Recap: the undergoing understanding and its object (“up to chapter five here on page thirty-nine”) #

Point: what has been established before chapter five.

1. Reason is an undergoing ability; since it sees the natures of all material things, it must lack any material nature.
2. Its object, what acts upon it, is the what-it-is of a thing sensed (a natural thing) or imagined (a mathematical thing).
3. What-it-is is distinct from the individual: what water is vs. the water in front of me; what a man is vs. this man; what a chair is vs. this chair. So the object of reason is universal, common to many.

2. Why a second power is needed (“singular when sensed, but universal when understood”) #

Point: individuals are not actually understandable, so something must make them so.

• Boethius, at the beginning of logic: the thing is singular when sensed, universal when understood.
• Reason does know the singular, but not directly: as the source from which its own thought is taken.
• Plato has no problem here, since for him universals exist by themselves in the world. Aristotle “elsewhere” denies this: understanding what a man is involves flesh, blood and bones, and flesh, blood and bones outside the mind are singular. So the question stands: what makes individuals actually understandable?

3. Two abilities, and the matter–art analogy (“intellectus possibilis”) #

Point: chapter five introduces a second power alongside the one treated so far.

• Latin names: intellectus possibilis, which he renders “the undergoing understanding” (able “in a way to become all things”, receiving the natures of all things); intellectus agens, usually transliterated “agent intellect”, which he renders “the acting upon understanding”.
• Aristotle’s opening argument: wherever something able to be actually comes to be, you need (a) something able to become it and (b) something that makes it actually become it. In the material world: wood can become chair, table or door, but something else (art) makes it actually a table. So in the understanding part of the soul: something receives the what-it-is of all things, but the what-it-is must be separated from individuals to be received, so there must be something “proportional to the art” that makes the potentially understandable actually understandable.
• Reading the text: “in every nature”, which Thomas glosses as every nature where something goes from ability to act; “the one like matter” is what is in potency (his preferred word: “ability”) to all things in that genus; “the other the cause” in the active sense, which brings about by making them all.
• Greek nuance he notes: the first nous is that “in which all things come to be” (he accepts “receive all things” too); the second is one “able to make all things”, more active in the Greek.

4. Hexis, habitus, and Thomas’s correction (“some people misunderstand what he means”) #

Point: the acting-upon understanding is called “like some state”, Greek hexis, Latin habitus, English “habit”, and Thomas warns against a misreading.

• Wrong reading: hexis means the habit of natural understanding. Thomas’s reply: even that habit presupposes the acting-upon understanding.
• Right reading: the broad sense in which natural philosophy opposes matter, or ability in general, to the act which is had, as against the lack of the act or form. The undergoing understanding’s nature is to be in potency, “like a blank tablet on which nothing is written”; the acting-upon understanding is like a form, an act, hence “something had”, a habit. Having vs. lacking: what can receive but has not yet received is said to lack, and lack is the opposite of habitus. This becomes clearer when Aristotle later calls it actual as against the undergoing understanding’s potency.

5. The comparison to light (“light makes what is potentially color”) #

Point: how the acting-upon understanding is like light.

• In a completely dark room no colours are actually visible; turn on the light and colours visible in ability become actually visible. As light is to the seeing of the eye, so the acting-upon understanding is to the seeing of the undergoing understanding: something becomes actually understandable and receivable because of its activity.
• Why this is not strange: recall the order of our knowledge. Sensing first; then memory of what we sensed; then gathering many memories of the same sort of thing (experience); then we are aware of an ability to separate out what is common to them. Dog in the yard, “There’s a dog, Blaine”; another dog another day; memories of yesterday’s and today’s dog; an experience of dogs, “nothing other than a collection of many memories of the same sort of thing”. Everything up to this point is singular, even experience; but what a dog is, the universal, is what is actually understandable. So a power is needed to separate the universal from the images of the singulars, and the separated universal is received in the undergoing understanding. Actual understanding results from both powers.
• Carrying of words: “to see” names first the act of the eye, then the imagination’s act, then understanding; likewise “light” is carried from what makes the potentially visible actually visible to what makes the potentially understandable actually understandable, by separating from individuating matter.
• Summary of paragraph one: two powers in the understanding part, one to receive the natures of all material things universally, one to separate the universal nature from the singulars in sense or imagination.

6. Four things said of the new power (337) (“It’s apathes”) #

Point: the second paragraph states four attributes of the acting-upon understanding.

1. Separable / separated (Greek chōristos; “you could have translated that separated”).
2. Unaffected, apathēs, in the first sense of “passion”, “maybe in other senses too”.
3. Not mixed with matter.
4. Because it is active, its substance is act rather than the passive potency that the undergoing understanding is.

• Student question: why distinguish unmixed from separable, since they are very close? He grants they are close; in the previous reading the more direct claim was that the mind is not a body, and also not mixed with matter. Neither, in the case of the undergoing understanding, would be allowed to prevent understanding all things.

7. Aside on Anaxagoras DK 12: unmixed vs. pure (“mixed with nothing”) #

Point: his own recent second thought on the fragment, offered as a parallel to unmixed/separated.

• Anaxagoras: mind is unlimited, self-ruling, mixed with nothing; then “the thinnest of all things” and “the purest of all things”. He used to think “purest” repeated “unmixed”; now: unmixed means not mixed with other things, purest means not itself a mixture of things. College “mixer”: mixing with other people vs. being oneself a mixture of flesh, blood and bones.
• Anaxagoras’s reason for “unmixed”: if mixed with things it could not rule them. His illustration: a judge must be impartial, not a part of those between whom he judges; with a financial interest in one party’s company he should not judge their squabble.
• “Thinnest” is really the reason for “purest”: if it were a mixture, its components would be thinner than it.
• Aristotle says something like these two things, in reverse order: not a body, and not mixed up with a body.

8. One reason for all four: the maker is more honourable (“more honorable than the one undergoing”) #

Point: Aristotle gives one reason for the first three attributes and in a way for the fourth.

• He prefers “the maker” to the translator’s rendering: the maker is always more honourable than what undergoes, the active principle than the matter. Teacher more honourable than student; Michelangelo than the marble.
• Argument: if the undergoing understanding is not a body, does not undergo as matter does, and is not mixed with matter, then even more so the acting-upon understanding; and because it acts, it must be as act rather than as matter or potency.
• The analogy: acting-upon is to undergoing as art is to matter. Art is actual; the form the artist will induce is already in act in his head, and exists in the matter only in ability until art acts. The proportion is “not altogether identical”, since the acting-upon understanding really acts upon the images, separating the common from the singular, and only in that sense acts upon the undergoing understanding.

9. Thomas’s question: potency and act to the same thing (“How can the soul be both in potency”) #

Point: how the soul can be both in potency and in act with respect to the same thing.

• Thomas’s answer as he gives it: the undergoing understanding is in potency to any determined material nature; those determined natures are in what we sense or imagine, in the images, but not yet actually understandable. The acting-upon understanding is actually immaterial and so makes them immaterial, receivable. So not ability and act in the same way.
• The determined natures are not in the acting-upon understanding; if they were we would not need images to learn, whereas in fact we come to know what a dog is through sensation, memory and experience. The natures are in the things, tied up with the individual, so not yet actually understandable or immaterial; the acting-upon understanding makes them actually universal and so actually understandable.
• “This is the key to understanding eventually the angels and God”: something becomes understandable when separated from matter, a sign that what is by nature immaterial is actually understandable; hence God and the angels naturally understand primarily themselves, whereas material substances are understandable only in ability.
• Aside: “some truth in what Immanuel Kant said” that things in themselves (material things) are not knowable: not knowable in act, but understandable in ability.
• Restatement: from one middle term, if the undergoing understanding is immaterial, not acted upon as matter, not mixed, then the maker, analogous to art, is so even more, and is in its substance an act, a form, a habitus, rather than a potency for form.
• Student remark (echoing Thomas): the act it has is its immateriality, and being actually immaterial it can make other things immaterial [ed.: transcript says “material”; sense requires “immaterial”]. His reply: yes, but it does not contain the definite natures of material things; those are found and represented in the images. There is something actual in the images not in the understanding until it sees them (so in that respect the understanding is in potency to the images), and something the acting-upon understanding has that the images lack, actual immateriality; it makes the image actually understandable by separating the natures from individuation. The recording ends mid-sentence.

His words #

• “undergoing understanding”: his rendering of intellectus possibilis, the understanding that receives the natures of all things [ed.: possible/passive intellect]
• “acting upon understanding”: his rendering of intellectus agens [ed.: agent intellect]
• “ability”: his preferred word for what is in potency [ed.: potency]
• “what it is”: the object of reason, distinct from the individual [ed.: essence/quiddity]
• nous: usually translated “understanding”
• hexis / habitus / “habit”: to be read broadly as “having” as opposed to lacking, not as the habit of natural understanding
• “blank tablet”: the undergoing understanding’s nature, in potency to receive all natures
• “experience”: a collection of many memories of the same sort of thing
• chōristos: separable, “or separated”
• apathēs: unaffected, in the first sense of “passion”
• “the maker”: his preferred rendering for the active principle in the honour argument
• “mixer”: college dance; mixing with others vs. being oneself a mixture

Texts #

Read in class

• Aristotle, De Anima III.5 (inferred), opening paragraph and paragraph 337: “in every nature”, “like some state, like light”, the four attributes and “the maker is more honorable”
• Thomas Aquinas, commentary on the same passage: gloss on “in every nature”, the correction on hexis, the question how the soul is both in potency and act

Mentioned

• Boethius, beginning of logic: singular when sensed, universal when understood
• Aristotle, “elsewhere”: what a man is cannot exist by itself, since it involves flesh, blood and bones
• Anaxagoras, fragment DK 12 (unlimited, self-ruling, mixed with nothing, thinnest, purest)
• Berquist handout, “An Introduction to the First Road in Our Knowledge”, p. 4 (verified source): sensing, memory, experience
• Plato (universals existing by themselves); Immanuel Kant (things in themselves not knowable)

His questions #

• What makes individuals actually understandable, since they are not actually understandable in themselves? A second power, the acting-upon understanding, which separates the universal from the images.
• Is hexis here the habit of natural understanding? No (Thomas): that habit presupposes the agent intellect; hexis means “having” as opposed to lacking.
• In what way is the acting-upon understanding like light? As light makes potential colour actually visible, it makes the potentially understandable actually understandable.
• Why distinguish “unmixed” from “separable”? (student) They are very close; the previous reading said both “not a body” and “not mixed with matter”; cf. Anaxagoras’s unmixed vs. pure.
• Why is the acting-upon understanding separated, unaffected, unmixed and act? Because the maker is always more honourable than what undergoes, as teacher to student, Michelangelo to marble.
• How can the soul be both in potency and in act with respect to the same thing? (Thomas) Not in the same way: in potency to the determined natures in the images, in act as actually immaterial.
• Are the determined natures of things in the acting-upon understanding? No; otherwise we would not need images; we learn what a dog is through sensation, memory and experience.
• Is there truth in Kant’s “things in themselves are not knowable”? Some: material things are not understandable in act, but they are in ability.