Metaphysics IX, Reading 5: Act Known by Induction and Proportion; Motion vs. Perfect Act

Orientation #

He opens by placing readings five and six as the second part of Book IX, where the emphasis falls on act, but “in a much more universal way than just what motion” — referring back to the first four readings, which treated ability as ability for motion. The neighbouring classes treat potency and act in Book IX with Thomas’s commentary.

The class, in order #

1. Ascent from the less universal to the more universal (“a little bit of the order, right, in wisdom”) #

The point: wisdom proceeds by ascending from a narrower consideration to a more universal one, and Aristotle’s move here is an instance.

• Parallel cases: substance — he begins with material substance and rises to an understanding of substance applicable even to material substances; the one — begins with the one that is the beginning of number (limited to the genus of quantity) and ascends to the one convertible with being.
• Aside on precision: Thomas, following Avicenna, says being is first understood by our mind; more precisely, the being we first understand is the being of material things. Hence when we speak of immaterial being we use thoughts fitted to material being.
• Boundary case, God: in material things there is a distinction between what a thing is and that by which it is what it is; in God there is none. So we use both concrete and abstract words of God and must negate the distinction — “we don’t have one thought to talk about God… we have two thoughts.”

2. Act exemplified, not defined (“Act, then he says, is the existence of a thing”) #

The point: Aristotle introduces act by cases rather than definition.

• Hermes in the wood (Hermes = Greek Mercury, messenger of the gods): the wood is a statue in ability, the shaped wood in act — so form is a kind of act. Michelangelo before the slab of marble: “someday I’ll make something out of it,” and made the Pietà.
• The half in the whole, “because it might be taken from”: a parallelogram with a diagonal drawn — the two triangles were there in ability first.
• A quite different kind of ability: the man able to consider a theorem of geometry but not actually considering it; going to the board and diagramming it is going from ability to act. Aside: at final exams he does the Pythagorean theorem at the board so as not to forget the proof.

3. Why act cannot be defined (“one should not seek a definition of everything”) #

The point: act is known by induction and proportion, not definition.

• The logical parallel: one should not seek to prove every statement. If every statement needed proof, you could not begin to prove — the statements used in the proof would themselves need proof, and so back. His favourite example: “statements exist”; the man who says statements do not exist is making a statement.
• Applied to definitions: if every part of every definition needed defining, there would always be a definition required before any definition, and we could never begin to define, so we would not know what anything is. But we do come to know things by definition (a rhombus, a rhomboid, a trapezium) — therefore something is known without definition.
• Descartes (“the so-called father of modern philosophy”) and Locke both deny motion can be defined and criticise Aristotle for defining it. His reply: Aristotle is the father of logic and knows perfectly well that not everything can be defined — but it is act, not motion, that is undefinable; motion can be defined through act and ability.
• How act is known: partly by induction, and by seeing a proportion — “proportion here is being used in Euclid sense, not for ratio, but for a likeness of ratios.”
• Aristotle’s proportions: builder actually building : house-builder; awake : asleep; seeing : having eyes shut but not blind; what has been formed out of matter : matter; what has been worked up : the unworked. He notes the first three are more like an activity or motion (house-building transitive, seeing remaining in the seer), while the last two set form proportional to motion. Hence act is said both of motion/operation and of form — “perhaps that’s the first distinction you can see among acts.”

4. Ways a name is equivocal by reason (“equivocal by reason of a likeness of ratios”) #

The point: “act” is not equivocal by chance; he gives two different ways of showing this.

1. By a likeness of ratios — as with “before,” and “in”/“out” in Physics IV, and “beginning” in the opening of Physics V. Form : unshaped wood :: my seeing you : my eyes closed though not blind.
2. By the ratio of the second to the first — from Thomas, “another text there in the De Potentia”: form is the end of motion and also the beginning of motion, since a thing acts through its form. Teaching results in a formation of your mind (form as end); once formed, the mind can teach others (form as beginning). Parallel: we call logic philosophy equivocally, but by the ratio of logic to philosophy as its tool — not purely equivocally, but not philosophy in the original sense.

• A student supplies “analogous”; he accepts and returns to “equivocal by reason.”

5. The seriousness of Descartes’ and Locke’s denial (“throwing out the definition of motion”) #

The point: denying that motion can be defined damages natural philosophy and natural theology.

1. Nature is defined (Physics II) as a beginning and cause of motion and rest in that in which it is, first, as such and not by happening. So if motion were unknown, nature would be unknown — hence Physics III defines motion by act and ability.
2. The definition of motion is later the beginning for seeing that nothing moves itself, which is the beginning for reasoning to the unmoved mover — “the first and most manifest argument for existence of God.” “Things in motion soon to catch the eye, but not stir us.” [ed.: his recurring tag for why motion is first called act]

• Descartes quotes a garbled version and says it is “just playing with words”; Locke says motion is a simple idea and the simple cannot be defined. Reply: even a point, which has no parts, can be defined as the end of a line; and motion is not simple in that way — it is always something of another, so there is a basis for multiplicity in its definition: “the act of what is able to be, insofar as it’s able to be.”
• Aside: as a young philosopher he thought he understood the definition of motion; his brother Richard laughed at him — he knew the words.

6. The fourth paragraph: not univocal, “in proportion as this and that, or towards that” #

“This in that” is said more of form in matter; “towards that” (the ability to see to seeing, the ability to hear to hearing) is used more of motion or doing. Some acts are as motion to ability, others as substance — “Aristotle’s annoying way of referring to form,” since from Book VIII form is especially substance.

7. An ability never fully actualised (“the continuous is that which is divisible forever”) #

The point: some abilities, unlike the ability to see or the wood’s ability to be a statue, are never satisfied.

• Bisecting a straight line always yields two shorter lines, never two nothings (the line would be made of nothing) and never two points.
• Argument against a line composed of points: to compose, points must touch; having no parts, no edge and no interior, two points can touch only by coinciding; coinciding they have no more length than one point, i.e. no length; and this holds for ten, a hundred, a million, or an infinity. “Your high school math teacher… was mistaken” — but his mistake is a sign of the difficulty of understanding that kind of ability.
• Cutting always makes actual a point that was there only in ability; you may go on as long as you like, and the ability is never satisfied. Time and motion are likewise continuous.
• Same with the increase of number (add one to any number), and with reflection: I know what a square is, I know that I know, I know that I know that I know — “this kind of sterile infinity.”

8. Motion versus perfect act (“we are judging and have judged”) #

The point: within act-as-doing, a subdivision by whether the end is contained in the act; the naming is the difficulty, not the distinction.

• Naming: Thomas says “for want of a name,” motion and operatio; “operation” is not altogether satisfactory; one could say motion and doing. Greek: kinēsis and energeia.
• Test by the tenses: walking home — while walking home, I have not walked home; when I have walked home, I am not walking home. So it is essentially an imperfect, incomplete act. Same for building a house, making dinner, reading a page, thinning, learning, becoming healthy.
• Seeing: while I am seeing you, I have already seen you — essentially a perfect, complete act. Same for judging, understanding a triangle, and loving (“when I’m loving you, have I loved you yet? — yes”).
• Text: acts which have a limit are not an end; but that in which the end is, is act properly. Aristotle adds the ethical instance: “at the same time we are living well and have lived well, and are happy and have been happy.”
• The weight of it: “this is important, you know, for the whole philosophy” — is the activity that will be our happiness an imperfect act or a complete one? Happiness must be the second kind.
• Grammar reflects the imperfect act more, which reflects that motion is what we first call act, since our knowledge starts from the senses and things in motion catch the eye.
• Asides: his philosophical friend whose wife knows not to interrupt while his eyes are on the page, but comes in with small talk when he looks up — precisely when he may be in perfect act. Professor Surik quoting Thomas, homo sedens fit sapiens — “the man sitting becomes wise” (he corrects “makes wisdom”: it is an adjective). Socrates stopping on the porch, standing still to think something through while his companion goes in to dinner.

9. Existence as act, and the transitive/immanent division (“Did God love us before He made us?”) #

• Aristotle here does not treat existence as an act. But Thomas in the Summa Contra Gentiles, on the separated substances, contrasts the composition of matter and form with the composition of a thing’s substance and its existence. So that sense of act comes after Aristotle’s: first motion as act, then form as act, “and perhaps last you would see existence or to be as an act.”
• Other division: transitive act (acting upon something outside) vs. operation remaining within the doer. Seeing, understanding, loving are intrinsic.
• Theological application: God loved us and chose us from eternity, since understanding and loving remain in the one understanding and loving. But He was not our Creator, Lord, ruler or shepherd before He created us — creation signifies an operation with something outside the Creator, and the shepherd is not shepherd before He has His flock.

10. Do the two divisions coincide? (“someone asked me, is everything intrinsic a perfect act?”) #

The point: the imperfect/perfect division and the transitive/immanent division do not simply coincide.

• No: learning is immanent but is more like motion — while I am learning I have not learned; when I have learned the Pythagorean theorem I am no longer learning it. But most perfect acts we meet are immanent (seeing, understanding, loving).
• The converse — is every transitive act imperfect? He raises whether some transitive acts are all at once: creation takes no time; when God is creating my soul, He has created my soul. A student proposes substantial generation; he agrees. With us, Aristotle’s examples (building a house, making a statue, making dinner, making wine) take time. He leaves the converse guarded: “you got to be a little careful.”

11. Manifesting the definition of motion (“coming into the room is the act of the ability to be in the room”) #

The point: a worked dilemma showing why the definition of motion needs “insofar as it is able to be.”

1. “Coming into the room is the act of the ability to come into the room” — true, but circular, so no definition.
2. “Coming into the room is the act of the ability to be in the room” — not circular, but false, since the act of that ability is being in the room.
3. Resolution: when coming into the room I am already partly in the room, so it is a partial or imperfect act of the ability to be in the room.

• Objection: the man standing in the doorway, one foot in one foot out, is partly in the room but not coming in — he is not moving. Reply: add “insofar as it is still able to be” — the act is ordered to a further actualisation. So “insofar as it is able to be” says two things: the act only partially completes the ability, and it is a partial actualisation on the way to a further one. This separates motion both from being fully in the room and from standing in the doorway.
• Parallel manifestation by learning: learning is not knowing; the ability to learn and the ability to know are not two abilities like walking and talking — it is by learning that the ability to know is actualised; and one learning is not entirely ignorant. So learning is an imperfect act of the ability to know, on the way to a further act. Boundary case: the student who withdraws mid-course, retaining a little but with no intention of knowing more — he is no longer learning, so “insofar as you are on the road to knowing more” is needed.

12. Plato and Aristotle on God’s motion (“Thomas in the commentary will mention”) #

Thomas notes Plato uses “motion” more loosely than Aristotle, covering both kinds. So the Platonists’ “God moves Himself and is the first mover” does not contradict Aristotle’s unmoved mover: Aristotle uses motion in the strict sense, for the imperfect act, while Plato means that God understands Himself and loves Himself. “He better, I think. It’s probable.”

His words #

• “reading” [ed.: lectio] — he notes it is sometimes translated “lecture”; “a little more relaxed” to say reading.
• ability [ed.: potency, dynamis] — what a thing can be or do before act.
• Natural Hearing [ed.: the Physics].
• proportion — in Euclid’s sense, a likeness of ratios, not a ratio.
• equivocal by reason [ed.: analogous] — a student offers “analogous”; he accepts.
• operation / doing — Thomas’s operatio, used “for want of a name” for the second kind of act; Greek energeia against kinēsis.
• imperfect / incomplete act — one in which “is doing” and “has done” cannot be said together.
• perfect / complete act — one in which the end is, said together with the perfect tense.
• transitive act vs. intrinsic (immanent) act — acting on something outside vs. remaining in the doer.
• sterile infinity — his phrase for the endless reflection “I know that I know that I know.”

Texts #

Read in class

• Aristotle, Metaphysics IX, readings (lectiones) 5–6 — paragraphs on the ability said according to motion; act as the existence of a thing (Hermes in the wood, the half in the whole, the man able to consider); “one should not seek a definition of everything” and the list of proportions; “not said in the same way… in proportion as this and that, or towards that”; the never-satisfied ability; “we are judging and have judged… loves and has loved”; “let it be clear then from these things… what and how it is to be an act.”

Mentioned

• Aristotle, Physics II (definition of nature), III (definition of motion), IV (senses of “in” and “out”), V opening (“beginning”), VII or VIII (nothing moves itself; the unmoved mover) — he is unsure which of the last two.
• Aristotle, Metaphysics VIII (form as especially substance).
• Thomas, De Potentia (form as end and beginning of motion) — “another text there.”
• Thomas, Summa Contra Gentiles, on separated substances (substance and existence vs. matter and form).
• Thomas, Commentary on the Metaphysics (Plato’s looser use of “motion”).
• Descartes and Locke, denying motion can be defined.
• Avicenna, via Thomas, on being as first understood.

His questions #

• Why does Aristotle not define act? Because not everything can be defined; act is known by induction and by a likeness of ratios.
• If every statement needed proof, would you prove any statement? No — you could not even begin; “statements exist” is known without proof.
• What did Descartes and Locke get wrong about motion? They denied it can be defined; but it is act, not motion, that is undefinable, and the damage reaches to the first argument for God’s existence.
• When you bisect a straight line, what do you get? Two shorter lines — never two points or two nothings; so the ability to be divided is never fully actualised.
• When I am walking home, have I walked home? When I am seeing you, have I seen you? No to the first, yes to the second — hence imperfect act (motion) versus perfect act.
• Is the activity that will be our happiness an imperfect act or a perfect one? A perfect, complete act, like seeing, understanding and loving.
• Did God love us before He made us? Was He our Creator before He created us? Yes to the first (loving is immanent); no to the second (creating signifies something outside).
• Is every immanent act a perfect act? Is every transitive act imperfect? No to the first — learning is immanent yet like motion; the second is left guarded, since creation and substantial generation are all at once.
• Is “coming into the room is the act of the ability to be in the room” a definition? Only with “imperfect act… insofar as it is still able to be,” which excludes both being in the room and standing in the doorway.
• Does Plato contradict Aristotle in saying God moves Himself? No — Plato uses “motion” loosely, meaning that God understands and loves Himself.