Thinking about Substance

The Development of Aristotle's Thought

The Aristotelian corpus does not divide into early, middle, and late works (as the Platonic corpus does), but the Outline of Categories 1-5:

Chapter 1. Names
Chapter 2. The division of reality
Chapter 3. Predicates
Chapter 4. The ten categories
Chapter 5. Substance
Categories (the first of the logical works) appears to be among Aristotle's earliest works and to have been written not long after he was in the Academy.

Because he makes no reference to forms in matter, Aristotle appears to have written the Categories before the Physics, On the Soul, and the central books of the Metaphysics.

The Categories, in this way, is a first attempt to do what Aristotle does in these works.

The Ontology in the Categories

"Of the beings: some are said of a subject but are not in any subject. Man is said of a subject, this or that man, but is not in any subject. Some are in a subject but are not said of any subject. By in a subject, I mean what is in something, not as a part, and cannot exist separately from what it is in. For example, the knowledge-of-grammar is in a subject, the soul, but is not said of any subject; and the white is in a subject, the body (for all color is in a body), but is not said of any subject. Some are said of a subject and in a subject. For example, knowledge is in a subject, the soul, and is said of a subject, knowledge-of-grammar. Some are neither in a subject nor said of a subject, for example, this or that man or this or that horse—for nothing of this sort is either in a subject or said of a subject. Things that are individual (ἄτομα) and one in number are, without exception, not said of any subject, but there is nothing to prevent some of them from being in a subject. Knowledge-of-grammar, for example, is one of the things in a subject" (Categories 2.1a).

"A substance--that which is called a substance most strictly, primarily, and most of all--is neither said of a subject nor in a subject, e.g. this or that man or this or that horse. The species in which the things primarily called substances are, are called secondary substances, as also are the genera of these species. This or that man belongs in a species, man, and animal is a genus of the species; so these--both man and animal--are called secondary substances" (Categories 5.2a).
To identify the parts of reality terms in the language signify,
"All the other things are either said of the primary substances as subjects or in them as subjects. ... So if the primary substances did not exist it would be impossible for any of the other things to exist" (Categories 5.2a).

"It is reasonable that, after the primary substances, their species and genera should be the only other things called secondary substances. For only they, of things predicated, reveal the primary substance. For if one is to say of this man what he is, it will be appropriate to give the species or the genus as the answer (though more informative to give man than animal); but to give any of the other things would be out of place--to say, for example, that he is white or that he runs or anything like that" (Categories 5.2b).

Aristotle is correcting the ontology in the Phaedo.

   "Let us then, Cebes, turn to what we were discussing before. Is the reality itself (αὐτὴ ἡ οὐσία), whose reality we give an account in our dialectic process of question and answer, always the same or is it liable to change? Does the equal itself, the beautiful itself, what each thing itself is, the reality, ever admit of any change whatsoever? Or does what each of them is, being uniform and existing by itself, remain the same and never in any way admit of any change?
   It must necessarily remain the same, Socrates.
   But how about the many things, for example, men, or horses, or cloaks, or any other such things, which bear the same names as those objects and are called beautiful or equal or the like? Are they always the same? Or are they, in direct opposition to those others, constantly changing in themselves, unlike each other, and, so to speak, never the same?
   The latter, they are never the same.
   And you can see these and touch them and perceive them by the other senses, whereas the things which are always the same can be grasped only by the reasoning of the intellect, and are invisible and not to be seen?
   Certainly that is true.
   Now, shall we assume two kinds of existences, one visible, the other invisible?
   Let us assume them, Socrates" (Phaedo 78c).

In Aristotle's ontology in the Categories, "the equal itself, the beautiful itself" are general properties and so are not substances at all, neither primary nor secondary substances.
Aristotle divides "the beings" (τὰ ὄντα) according to whether they are "said of a subject" or "in a subject."

This results in a partition of reality into four kinds of things. There are (i) individual objects, (ii) individual properties, (iii) general objects, and (iv) general properties.

The individual objects are the most fundamental of the four. The others depend on these objects for their existence. To mark this, Aristotle calls them "primary substances."

To see some of the implications of this ontology, consider the following two sentences:

Socrates is a man.
Socrates is white.

The term 'Socrates' in these sentences signifies an individual object, Socrates. The term 'man' signifies an object too. According to Aristotle, 'man' signifies a general object, man.

This can be surprising.

It is natural to think individual human beings exist, but man does not seem to exist.

Aristotle's understanding of the truth of the second sentence can be surprising too.

Aristotle thinks that if this sentence is true, then the individual property the term 'white' signifies is in the individual object the term 'Socrates' signifies.

Things get even stranger when think about the individuality of Aristotle's individual objects.

The Oneness of Individuals

Socrates is one thing, not some things heaped together over time. The philosophical problem is to explain this oneness. Aristotle knows this and gives an explanation.

"For the primary substances, it indisputably true that each signifies a this; for the thing revealed is individual [or "atomic" (ἄτομον)] and one in number" (Categories 5.3b).

In the Categories, the objects ("this or that man or this or that horse") Aristotle identifies as primary substances are individuals because they are the "atomic" parts of general objects.

Aristotle thinks the general object animal is divisible into more specific general objects, such as man. Man is not further divisible into general objects, but it is divisible into the many individual men (Socrates, Plato, and so on). These men are indivisible (because the parts of human beings are not human beings) and hence they are the "atomic" parts of the object man.

This is supposed to be the explanation for why Socrates is "one in number."

Problems in the Ontology

Aristotle seems to think again about substance in the Metaphysics because he realized that the "this or that man" of the Categories do not meet the conditions for substance.

Here is the problem.

The "this or that man" is a concrete object that possesses properties. It is some human being with

We ordinarily think that it is possible for Socrates to become pale, but it is not clear that this change can be accommodated within the ontology in the Categories. We need something more basic than Socrates as what persists, but there is nothing in the ontology to play this role.

"[W]hat is most characteristic of substance appears to be this: that, although it remains, notwithstanding, numerically one and the same, it is capable of being the recipient of contrary qualifications. Of things that are other than substance we could hardly adduce an example possessed of this characteristic. For instance, a particular colour, numerically one and the same, can in no wise be both black and white, and an action, if one and the same, can in no wise be both good and bad. So of everything other than substance. But substance, remaining the same, yet admits of such contrary qualities. One and the same individual at one time is white, warm or good, at another time black, cold or bad. This is not so with anything else" (Categories 5.4a).
a certain height, weight, and so on. So it is unclear what "this or that man" is such that it is a subject distinct from its accidents (the height, weight, and other properties it possesses).

This forces Aristotle to think again about what things are substances.

The positive conclusion he reaches remains a matter of debate among historians, but there is general agreement that the primary substances in the Metaphysics are not the primary substances of the Categores. These objects in the Categories are the objects familiar from experience: concrete objects of a certain size, weight, color, and so on.

It also seems clear, as we will see in the next lecture, that Aristotle no longer believes in the general objects ("man" and "horse") he identified as secondary substances. So in the Metaphysics he can no longer accept the explanation he works out in the Catagories for the oneness of "this or that man." In the Metaphysics, because general objects do not exist, Socrates cannot be one thing because he is an atomic and thus indivisible part of the general object man.

Thinking again about Substance

Now we can see little more clearly why Aristotle proceeds in the Metaphysics as he does.

It is natural to think that as we live our lives, Socrates and the other individuals we meet are real. Once, however, we identify them as primary substances, we must explain how they are separate from their accidents, and once we conclude they are not the primary substances, it is unclear what is. So, in the Metaphysics, Aristotle sets out conditions for substance ("this," "subject," and "separate") and investigates whether anything meets them.

The general objects ("man" or "horse") Aristotle identifies in the Categories as secondary substances do not meet these conditions. The same is true for the individual objects ("this or that man" and "this or that horse") he identifies as primary substances.

So, with Plato in his background, Aristotle investigates whether there might a way of thinking about forms so that they meet the three conditions for being a substance.

We can understand this if we imagine Aristotle thinks about concrete objects to discover what in them meets the conditions for being a substance. Socrates can exist without any particular height and weight, but he must have some height and weight or other. This can suggest that although he is a concrete object and so cannot exist without certain properties, there somehow is also a persisting underlying object that needs no particular such properties to exist.

This leaves the question of what this persisting object is.

If we look to what Socrates is for the answer, then we can begin to understand how Aristotle might begin to think there is a way for forms to be a "this," a "subject," and "separate."

What appears to persist unchanged when Socrates changes in height or weight is an organization of flesh, blood, and so on, that makes him be a human being. This organization cannot exist apart from the material it organizes into a human being, but the organization also appears to Aristotle to be separate in account from the material it organizes.

Forms are Substances

We can also begin to see that thinking about how the forms of natural bodies are substances would lead Aristotle to think that these forms are substances with qualification.

Aristotle thinks that a soul (the form of a living natural body) is a substance with qualification because it is a "first actuality." It is an organization that contains unrealized potentialities. Human beings have the potential to walk, but this potential is not always actualized.

This suggests that Aristotle is working with the possibility that existence as an actuality without potentiality is the fundamental way of being a form and a substance.

This in turn provides some insight into how first philosophy is universal.

If divine substances are forms, it falls to theology as first philosophy to explain what existence as a form is. The explanation will be that forms exist as actualities that do not involve any potentialities. They are "pure" actualities. Further, because the explanation of existence as a "pure" actuality includes an explanation of existence as an "impure" actuality (an actuality involving potentialities and so an actuality with qualification), theology explains the existence or being of the forms in matter that physics studies when it studies sensibble substances.

Many questions remain about Aristotle's view that forms are substances. They are all difficult to answer, as Aristotle discussions themselves are exploratory, but we can get some insight into his thinking if we turn to his change of mind in the Metaphysics about the existence of the general objects he had identified as secondary substances in the Categories.

Perseus Digital Library

Aristotle, Metaphysics

Henry George Liddell, Robert Scott, A Greek-English Lexicon

ἀκίνητος, akinētos, adjective, "immovable"
ἄτομος, (ἀ + τέμνω), atomos, adjective, "uncut"
μεταβολή, metabolē, noun, "change"
μεταβάλλω, metaballō, verb, "turn about, change, alter"
χωριστός, chōristos, adjective, "separable"

Arizona State University Library: Loeb Classical Library.
Aristotle, Categories, Physics I-IV

"In the Metaphysics, Aristotle denies that there is anything general--at least, he denies that there are kinds [animal, man, and so on] into which objects fall. Thus, he also abandons the notion of an individual which he had relied on in the Categories, since it presupposes that there are general things, that there are universals" (Michael Frede, "Individuals in Aristotle," 50. Essays in Ancient Philosophy, 49-71). "In the Metaphysics, Aristotle denies that there are genera or species [animal, man] that is, he denies that universals really exist (cf. [Metaphysics] Z 13). Yet, if there are no genera and species, individuals no longer can be taken to be the ultimate, indivisible [or "atomic"] parts of genera [as he claimed in the Categories]" (Michael Frede, "Individuals in Aristotle," 63. Essays in Ancient Philosophy, 49-71).

"[In the Metaphysics, Aristotle] sees that it cannot be the ordinary objects of experience [this or that man, this or that horse] that underlie the properties, if there are to be properties in addition to the objects; for the ordinary objects of experience are the objects together with their properties—an ordinary object has a certain size, weight, temperature, color, and other attributes of this kind. So, if we ask what is it that underlies all these properties and makes them the properties of a single object, we cannot answer: just the object. For the object, as ordinarily understood, already is the object together with all its qualities; what we, however, are looking for is that which underlies these qualities. Thus we can see why Aristotle now considers answers like 'the form' or 'the matter' when considering the question, what actually is the underlying substance" (Michael Frede, "Individuals in Aristotle," 64. Essays in Ancient Philosophy, 49-71).

"Although [in the Metaphysics] he retains the primary substances of the Categories, namely objects, these must now yield their status as primary substances to their substantial forms which now come to be called primary substances. The substantiality of concrete particulars [this or that man] is thus now only secondary. The idea of the Categories that substances are that which underlies everything else is retained, as we see from Metaphysics] Z 1 and Z 3. However, the answer to the question what is it that underlies everything else has changed: now it is the substantial form" (Michael Frede, "The Title, Unity, and Authenticity of the Aristotelian Categories," 26. Essays in Ancient Philosophy, 11-28).

"Aristotle thinks that substances are not as such composite. There are substances that are pure forms, as e.g., the unmoved mover. And it is clear from [Metaphysics] Z 3,1029 b 3ff. and Z 11, 1037 a 10ff. (cf. also Z 17, 1041 a 7ff.) that Aristotle thinks that the discussion of composite substances in [Metaphysics] Z [and Metaphysics] H is only preliminary to the discussion of separate substances. We start by considering composite substances because they are better known to us, we are familiar with them, and they are generally agreed to be substances. But what is better known by nature are the pure forms. Aristotle's remarks suggest that we shall have a full understanding of what substances are only if we understand the way in which pure forms are substances. This, in turn, suggests that he thinks there is a primary use of 'substance' in which 'substance' applies to forms. Particularly clear cases of substance in this first use of 'substance' are pure forms or separate substances. It is for this reason that composite substances are substances only secondarily" (Michael Frede, "Substance in Aristotle's Metaphysics," 79. Essays in Ancient Philosophy, 72-80).

"[S]ubstantial forms rather than concrete objects are the basic entities. Everything else that is depends on these substantial forms for its being and for its explanation. Hence substantial forms, being basic in this way, have a better claim to be called 'ousiai' [οὐσίαι] or 'substances' than anything else does. Some of them are such that they are realized in objects with properties. But this is not true of substantial forms as such. For there are immaterial forms. Properties, on the other hand, cannot exist without a form that constitutes an object. Moreover, though certain kinds of forms do need properties for their realization, they do not need the particular properties they have. The form of a human being needs a body of a weight within certain limits, but it does not need that particular weight. No form needs that particular weight to be realized. But this particular weight depends for its existence on some form as its subject. In fact, it looks as if Aristotle in the Metaphysics thought that the properties, or accidental forms, of objects depended for their existence on the very objects they are the accidental forms of, as if Socrates' color depended on Socrates for its existence. However this may be, on the new theory [in the Metaphysics that supercedes the theory in the Categories] it is forms that exist in their own right, whereas properties merely constitute the way forms of a certain kind are realized at some point of time in their existence" (Michael Frede, "Substance in Aristotle's Metaphysics," 80. Essays in Ancient Philosophy, 72-80).

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