Notes on Aristotle’s “Metaphysics” Book VII


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NOTE: [These are my notes on the seventh book of Aristotle’sMetaphysics, also called book “Z” or “Zeta”. It concerns the concept of “substance” (ousia), or in other words “the ‘most real’ sort of thing that is”. It shows how Aristotle defends his views against both idealism and materialism. In my view, this can be well adapted to modern debates e.g. concerning reductionism and physicalism and I hope that it is clear how I think this is so.


Something to think about while you read this.


One item that puzzled me at first and that paid off my inquiry was the variety of things that were claimed by Aristotle as being “substance”. From a modern perspective, it seems that atoms and molecules are substantial, and an organism is also substantial, but the are not “substantial” in the same way. How can some thing be equally substantial as something from which it is made? Why can some substances include other substances as their material constituents, even though substances are not merely matter in their own right? In the end, I think that there is an explanation for this that includes both Kantian and evolutionary ideas, but this will have to wait for another blog post. I hope I address many of the concerns raised by the fact that the creatures who implement the highest categories of reason evolved through a contingent process in time and space. If you really pay attention to my description of the relation of elemental and biological substances but below and in a previous post on the “Physics”, you will see it.}

VII.1 What is “substance”?

“Substances”, in the sense used by philosophers, are objects which are “really real”. In Book Zeta, Aristotle claims that the question “What is ‘substance’?” is the most important question of philosophy, the one that is implicit in all previous thought without being openly stated. In Book IV (Gamma), Aristotle claims that prior to him, all other thinkers differed primarily on this one issue, and broadly speaking they had one of two positions on the subject:

  1. Materialism – These were the those who thought that “The Arkhe” or “Substance” was some type of matter, either fire, water or possibly atoms. Since this material underlay all real things and persisted through their birth and decay, it was more realin their view. In their view, matter was substance. Matter has the following advantages:
    1. It is the bearer of attributes, but nothing else bears it as an attribute.
    2. Before anything can come to be, its matter must first already be.
    3. Matter is immediately and obviously sensible whether or not it is known or perceived.

    The disadvantage of matter is that it lacks “what-it-is-ness” it is an atom or molecule are substances, but an aggregate of H2O molecules is not a substance in this same way.

  2. Idealism – Idealists believed that there were non-material things which were both eternal and more knowable than matter, which in their view made them more real. Idealists include Plato and Pythagoras. In their view, abstract beings (ideas or numbers) were substance. This view has the following advantages:
    1. Ideas are eternal.
    2. Ideas are necessary; the cannot not be as they are.
    3. Ideas are unchanging.
    4. Ideas are the “whatness”, the essence that make each thing the sort of thing it is. Once a thing loses this essence, it ceases to exist. Thus even the being of sensible things depends of ideas.

So for each of these opposing schools, we see that they both have reasons to define a certain sorts of things as “more real” than other sorts of things. Everyone sees that most things have some sort of reality, but some things are more realthan others. Aristotle proposes to focus on this issue of being “more real” by comparing all the possible candidates for “most real” things. In his philosophy the most real category of being is called “substance” (in Greek – “ousia”, meaning “land”). His method includes the following:

  1. First he looks at the major philosophical theories of substance, dividing them up as we did above.
  2. Then he lists those things which are commonly thought of as being substantially real, such as fire, air, organs, organisms, etc.
  3. Then he looks at those qualities that seem to make up the “substantiality” of the various types of substances people seem to believe in. These include:
    1. Matter
    2. Essence or Form
    3. The Composite of matter and form
  4. Warning: Aristotle uses the word “substance” in two related ways that might be confusing, First of all, there are:
    1. Substance1– “substances” as the “really real things” we have been talking about and then there is
    2. Substance2 – the “substance OF the substances”; that aspect of substances which is what makes it a substance and not merely an aggregate of smaller substances.
    3. In other words, every substance1is a substance1because it hassubstance2.  {In the case of humans, each human is a human because its matter has the form of a human; this can mean the outward form, but if can also mean the inner essence that causes the outward form to be – i.e. one’s genome and the cellular machinery that uses the DNA to make proteins into a human.}

Ch. 1 – Being as Substance

  • ” ‘Being’ has many senses. (See Metaphysics Book V.vii and the Categories)
    • But “being” denotes first “what a thing is” (its individuality and nature) and only secndarily the other categories.
    • All that is is either substance or “a determination of a substance” (some other category).
    • Non-substances (other categories) cannot exist independently or separated from substance.
  • How is substance primary?
    • “In definition”
      • “If we say something is ‘good’, that is not really meaningful unless we know the substance of which is is said.
        • An organism is “good” if it has high fitness or health, whereas
        • a logical proof is good, if it is valid and interesting.
        • A poem is good in a whole different way.
        • In this sense, substance is prior in defintion.
    • “In knowledge”
      • We cannot know if something is “big”, “yellow” or any other predicate unless we know what sort of substance it is.
    • “In time”
      • Because actual substance is always temporally prior to all its other categories.
      • Before a thing a be good, or red or, tall, it must first be a human or a dog or some other sort of substance. If we are only speaking of a possible tall human, then the goodness is likewise merely possible as well.

Ch. 2 – Opinions on substance.

  1. Many things are commonly accepted as substance.
    • Organisms
    • Parts of Organisms
    • Elements
    • ‘And their different species’
    • “and their parts and what is compounded of them, e.g. the physical universe and its parts (the stars, the Moon, and the Sun).”
  2.  Are all of these substances? Are there any other substances?
  3. Pythagoras says that numbers and geometrical forms are more substantialthan matter.
  4. The physiologoireject nonsensible substances.
  5. Plato
    • accepts geometry and adds Forms;
    • rejects material substances.

Ch. 3 – Substance as Substratum

  • There are four strong candidates for substance:
    • Substratum – the underlying concrete being
    • Essence – the Form of the thing
    • Universal – the definition of the essence, for example the data from sequencing a genome or the design of an artifact.
    • Genus – higher level universals, since they are more general, and on one view are thus more substantial.
  • Possible substrata:
    • Matter
    • Sensible Form of the individual being
    • Hylomorph – the matter/form compound – both of the above in concert.
  • Any of these could be “that which has predicates but is not predicated of another.”
  • If we define it over-simply thus, it seems that matter is the most likely substance the substance.

Ch. 4 – What has essence?

  1. “Essence” is :
    • What a thing is of itself
    • What a thing is in virtue of itself.
  2. Essence is NOT:
    • “A musical person” – accidental quality of substance.
    • “A white surface” – accidental quality of form.
    • “A white man” – accidental quality of substance.
    • “A cloak”
      • artificial product.
      • compound
        • of material elements
        • of matter and form by skill, not nature. This is because the form of the artifact is only partially in the artifact; in another sense it is in the workman. However, it serves well in many of Aristotle’ examples to illustrate “matter”, “form” and other concepts.
  3. Essence belongs to:
    • Substance “primarily and simply”
    • secondarily to all other Categories, which are said to “be”
      • By equivocation
      • In a qualified sense
        • We know that something is unknown
        • In the sense that nothing “is”.
      • Analogically as in:
        • “Surgical” (tools, practitioners, patients, supplies, rooms, schools, books, techniques, data, terminology)

Ch. 5 – Have coupled terms essence of definition?

This chapter deals with the essences of coupled terms like “white man”, white surface”, “musical man”, or “female human”. It is clear that the separated terms have essences in some sense; what about the compound terms taken jointly?

Essential attributes.

  • Noses are either concave or snub(per se attributes).
  • Animals are either male or female.
  • Quantities are either equal or not.

But whiteness is a NONessential attribute of man.

“Essence” is said analogously or in a different sense in both substance and other categories.

“Thus in one sense there will be no definition or essence of of anything except substances, while in another sense the remaining categories also have them. And so it is manifest that definition is the formula of the essence, and that essence belongs only to substances or to them alone in the proper, primary, and unqualified sense.”

[It seems that nonsubstantial essences are merely classificatory, while substantial essences have other senses:

  • Living essences have their form as their essence.
    • The genotype is the essence, in the following sense:
      • the genotype is nonsensible
      • the genotype is the cause of being is and temporally prior to the phenotype.
  • Molecular essences are the the molecules interface with other molecules; in other words, those aspects of the molecule that make it a suitable substratum for biology.
  • Atomic essences are the properties of the atom (atomic weight, outer electron shell configuration) that determine its chemical behavior.

Notes about these essences:

  • Lower-level substances (e.g. atoms )are “subsumed” into the essences higher level substances. (e.g. molecules).
  • The essence of the living substances is their encoded genotype (informed matter).
  • The essence of non-living substances is their interface with living creatures.]


Ch. 6 – Is a thing the same as its essence?

Two questions:

  • Does “The being” = “The being’s substance”?
  • Does “the being’s substance” = “the being’s essence”?
  1. Q: Why would the essence of the subjects of accidental predication be identical on the view that “a thing = its essence”? After all, it is its essence.
    • A: In one sense, the essence of “white man” and “black man” are the same, since both are “men” and the color is non-essential.
  2. What about per seexpressions?
    • Assuming the (Platonic)? Forms:
      • IF – Essence = Form
      • AND – Form = “ontos on” (thing in itself ?).
      • THEN – Essence is the things themselves. [substance?]
    • “That each individual thing is one and the same as its essence. … is clear … from the fact that to know the individual thing is to know its essence.”


Ch. 7 – Analysis of the Generation of Substance.

  1. Things Belonging to any of the categories may come into being in many ways.
    1. From many types of causes
      1. nature
      2. art
      3. spontanaeity
    2. Genesis is effected:
      1. BY something (efficient cause)
      2. FROM something (material cause)
      3. FOR something (final cause)
  2. “Some artificial, like some natural, products are also produced spontaneously and by chance; for sometimes, even in the natural sphere, the same things are generated both from seed and without it.” (from History of Animals (eels, fish, testaceans, insects) as well as(Physics?)”2.9″”
    1. Processes of production are analyzed in this section in two ways:
      1. By process:
        1. First the thought
        2. Then productive action
      2. Modes of speech
        1. “From sickness to health” – (not a health from sickness)
        2. “Statue made from stone” – (not from stone to statue)

Ch. 8 – What is generated? The “Hylomorph”

Q: When a substance comes into being, what is it that does so? Form, matter or both?

A: The “hylomorph” (compound of form and matter) comes into being.

“… We do however, cause a bronze sphere to ‘be’ inasmuch as we produce it from bronze andsphere; we put the form into a given lump of matter and the result is a bronze sphere. But if the essence of sphere were produced, it would have to be produced out of something; for what is produced must always be divisible and be partly one thing and partly another – partly matter and partly form.” … “Clearly, then the Forms (if there are such things) do nothing to explain generation or substances, and therefore cannot be considered self-subsistent substances.” Because substances cannot be predicated of another substance.

“Living creatures indeed are more truly substances than anything else, and in their case, if in any, we might expect to discover forms. But no, the begetter is adequate to generating the product, i.e. to putting the form into the matter. The completed whole, a certain form in a certain flesh and bones, is Callias or Socrates; but they are different by virtue of their matter, but the same in form, which is indivisible.” [Note the contradiction with Charlotte Witt’s thesis of individual essences.]

“If then we make the spherical form itself, clearly we should have to make it from some thing, and the process will go on like thatad infinitum.” [But given that the form is ‘made’ (by phylogeny or stellar nuclear synthesis) is it not made from existing “relative form” or ‘intelligible form’?]

Ch. 9 – Production: Autotmatonand non-substances.

“And here is a peculiarity of substance: there must pre-exist in actuality some other substance which produces it, e.g. an animal in the case of animal generation, but a quality or quatity need not necessarily pre-exist otherwise than potentially.” [On the modern view of cosmic and biological evolution, this is not true; nuclear synthesis and phylogeny both generate substances without actual pre-existence.]

Ch. 10 – Parts and Whole

Q: Does the definition of a whole contain that of its parts? What parts are prior to the whole?

n this section, Aristotle is resolving a paradox that comes from speaking of “part” in two different senses: the physical parts (e.g. atoms, molecules, organs, etc.) and the parts of the definition (e.g. the genus and the differentia), and the parts of the compound of these two. His example is a circle of which there are two halves that form semicircles. Now if we look at a concrete circle, the obviously in one sense the two halves are part of this, since they are each half the matter of the original. So in this sense, the semicircles are part of the circle. But if we look at the essence of the circle (or more specifically, the definition (horismos or logos) of the essence), then we see that semicircles are not part of the essence, although they can be deduced from the essence. The parts of essences are the genus and differentia. For circles, the genus is “bounded two-dimensional space” and the species or difference is “boundary = all points equidistant from the center”. In neither of these are “semicircles” mentioned. Since semicircles are not part of the essence of circle, the in this sense semicircles are not part of the circle. You can only define a semicircle by taking an existing circle and divining it in halfThe circles are essentially prior to the semicircles, and are only in each circle as potentials to be created, not as an essential part. In the previous example, the semicircles that made up the actual circle were meant in the sense of “the matter of the semicircle”, and in this case as well only the matter was actual. That two parts qua parts were only there in potentiality.

But when we come to the concrete thing, e.g., this circle, i.e. one of the individual circles, whether perceptible or intelligible (I mean by intelligible circles, the mathematical, and by perceptible circles those of bronze and wood) – of these there is no definition, but they are known by the aid of intuitive thinking or of perception; and when they pass out of this complete realization it is not clear whether they exist of not; but they are always stated and recognized by means of the universal formula. But matter is unknowable in itself. (1036a5)

So the matter in the semicircles are not knowable qua matter but only by virtue of being shaped like a semicircle and of being part of a full circle. In it interesting here that when he says “individual circles”, this could mean either perceptible material circles or intelligible mathematical circles. It may seems weird to call an ‘intelligible”mathematical” circle a “particular”, but perhaps he is referring to the particular intellect of the one who is thinking of the circle. Since the thinker is one, then in this sense the mental idea of the circle is also one particular circle. And immediately following this, he says something rather weird:

And some matter is perceptible and some intelligible, perceptible matter being for instance bronze and wood and all matter that is changeable, and intelligible matter being that which is present in perceptible things but not qua perceptible, i.e. the objects of mathematics. (1036a12)

It is one thing to (foreshadowing Occam) speak of abstracta having a sort of existence in the particular intellect, but “intelligible matter” sounds doubly weird.

Regarding the objects of mathematics, why are the formulae of the parts no parts of the wholes; e.g. why are not the semicircles included in the formula of the circle? It cannot be said, “because these parts are perceptible things”; for they are not. But perhaps this makes no difference; for even some things which are not perceptible must have matter; indeed there is some matter in everything which is not an essence and a bare form but a ‘this’. The semicircles, then, will not be parts of the universal circle, but will be parts of the individual circles, as has been said before [cf. 1035a30-b3]; for while one kind of matter is perceptible, there is another which is intelligible. (1037a)

Ch. 11 – Parts of the Form / Concrete Whole

Q: Essence seems to be mostly about form. Are there essences which “include” matter? Circles clearly are the former, but “animal” clearly includes matter in the definition.

A: Living creatures are essentially animate. meaning the are defined by movement of matter in space and time. A dead hand is only a ‘hand” equivocally,for it lacks the essentiall principles of change needed for a complete substantial hand.

“With regard to mathematical objects, why are they not the definitions of the parts included in those of the whole; e.g. why is not the definition of the semicircle contained in that of the circle? Not because they are sensible objects, for they are not … semicircles, then, are not part of the universal Circle, but of particular circles,”…

We have stated generally:

  1. What essence is and how it is self-subsistent. (ch. iv)
  2. What sorts of definitions include parts of do not. (ch. v, x, xi)
  3. That material parts have no part in the definition. (ch. v, x, xi)
  4. “Thatprimary substances (ch. vi) e.g., crookedness, (??????????) are the same as their essences, while concrete things involving matter are the same as their essences.”
    1. Concrete things cannot be defined, and all parts of the thing are parts of the thing
    2. But the definition or essence can be defined, and the parts of the concrete thing are not the parts of the essence.


Ch. 12 – [Nothing here folks, move along.]

Ch. 13 – Universal is not substance.

  1. a) A thing’s substance is peculiar only to it and nothing else. b) Substance is not predicated of a thing; whereas universals are always predicated of another.
  2. Perhaps universal is merely included in the essence as “animal” in “man” or “horse”. In that case either:
    1. It must be definable. [And thus contain another universal as defining element.] OR
    2. If not all elements are definable, then some are and thus a) above must be true
    3. It is impossible that individual of substance, if composite, should be composed not of substance or individuals but of qualities. [The qualities are not prior to substance in definition or time.]
    4. If “animal” were substance, then the substance Socrates would contain another substance “animal”.
  3. No common predicate denotes a “so-and-so”, rather “such-and-such”.
  4. A substance cannot contain “other substances existing actually”. [But does not a living substance consist of elemental substances?]

“Substance is definable in one sense and not in another.”

Ch. 14 – Forms are not substances.

This chapter looks at further problems with Platonism:

  • Making Forms substances.
  • Making Forms separate from concrete individuals.\
  • Resolving species into genera and differentia.

Ch. 15 – Forms are not substances, continued.

“Substance” is twofold:

  1. The “concrete thing” – the “hylomorph” (form and matter compound)
    • capable of destruction.
    • NOT demonstratable by reason.
  2. The Form – The substance of the concrete thing.
    • NOT capable of destruction.
    • Demonstratable by reason.
  3. Can the Form be defined?
    • Each Form is singular.
    • Which is the overlap of other universals.
    • But universals apply to many, as do any set of universals.
    • Even collections of universals that happen to have only one existing examplar COULD have more. (For example, if you created a copy of the Sun, it could still never be theSun).
    • [So if the Form is substance, then how could it be many? Since substance has predicates but never is a predicate.]

Ch. 16 –

  1. Of the substances, most exist only “potentially”.
    1. Parts of animals.
      1. Do not exist separately.
      2. When separated are merely matter, losing their form.
    2. Earth, fire, air – “None are one, but they are like a heap.”
    3. One might suppose that parts of animals exist “in act” (i.e. are substances?), YET:
      1. Parts exist only potentially.
      2. For parts are connected “by nature”, not “by violence” (biai) or by growing together.
  2.  Universal not substance of a concrete thing.
    1. On ‘x’ = an ‘x’ thing/itself.
    2. The substance of one ‘x’ is one.
    3. No universal can be a substance or the substance of a thing.

Ch. 17 – “The True View of Substance”

There are two ways of asking “Why is ‘x’ a ‘y’?”:

  1. “Why is man an animal?” – Because the from of  animal is in the form of man.
  2. “Why is this matter a man?” – Because the matter has taken the form of man.

A compound which forms a unity (“hylomorph”, meaning “matter-form”):

  1. is not merely an aggregate of material elements. (Gk. “hyle“)
  2. but also includes something destroyed by dissolution. (The Form, “morphe” or “eidos“, not the form itself, but the particular instance of the form that was in the particular bit of matter.)

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One thought on “Notes on Aristotle’s “Metaphysics” Book VII

  1. Pingback: Notes on Aristotle’s “Metaphysics” Book III | Zoon Echon Blogon

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