Aristotle's Metaphysics is concerned over all with the question: What is substance? Substance is also a primary subject of attention in the much briefer Categories. How are these two accounts related? I would like to suggest a number of points of contact that may help put Aristotle's project in the Metaphysics into a clearer light.
To that end, here are some notes. Careful-these are unfinished, and they may turn to gibberish by the time you reach the end.
A good place to begin is with the very beginning of the Categories, in which Aristotle makes a distinction between homonymous and synonymous things. Though these terms look just like English words, it's a good idea to pretend that you've never seen them before: those English words are just close enough to Aristotle's in meaning to be seriously confusing. Here are Aristotle's definitions:
Homonymous things, not words. The first point to notice is that these define relationships of things, not of words. In English, homonymy and synonymy are relationships between words. Two words are homonyms if they sound alike but have different spellings, or at least different meanings, and two words are synonymous if they have different sounds (or at least spellings) but the same meaning. From a modern philosophical viewpoint, this at once raises questions about whether it is words or occurrences of words that are homonymous or synonymous and what the identity conditions are for words. Those issues do not really arise for Aristotle's distinction, however, since for him it is things, not words, which are homonymous or synonymous. 'Homonymous' really means 'like-named', and 'synonymous' means 'named together.' Things are homonymous, in Aristotle's sense, if the same word applies to them both but not in virtue of the same definition, and things are synonymous if the same word applies to them in virtue of a single definition.
Aristotle gives as an example a human being and picture. The Greek word zôion (usually translated 'animal') applies to these both, but with different definitions: it applies to a human being because a human being is a certain kind of living entity, whereas it applies to a picture because the Greeks used this same term of drawings or illustrations (rather like our use of the word 'figure'). For an English example, a fingernail and a roofing nail are both called nails, and a fingernail file and a computer file are both called files, but in each case with different definitions.
Homonymy and the snares of language. Though Aristotle doesn't mention this criterion, one frequent characteristic of homonymous things is that they usually don't remain homonymous under translation. Aristotle's own example illustrates this: there is no single English word that reproduces the two uses of Greek zôion to mean both 'animal' and 'figure'. In the same way, my English examples with 'file' and 'nail' don't translate into most other languages. We might want to describe these as mere linguistic coincidences, accidental results of the way some particular language has developed, which do not point to anything deeper about the world.
Coincidental homonyms. The examples Consider the word 'pen' in the following three sentences.
There is obviously no common definition of 'pen' that fits all three of these cases. In fact, it is a mere accident of the history of English that we use 'pen' for each of these. The first 'pen' is derived from Latin 'penna', 'feather,' reflecting the practice of writing with quill pens; the second descends from an Anglo-Saxon word , meaning a corral or enclosure; and the third is a slang abbreviation for 'penitentiary.' The fact that we call a fountain pen, a playpen, and a prison by the same name thus reflects no very interesting similarity about them, only a curious fact about the history of English
Both Plato and Aristotle were well aware that such linguistic coincidences can be exploited by people bent on deceiving in argument. Aristotle, in fact, wrote an entire treatise (On Sophistical Refutations) about fallacious arguments and how to deal with them, and the exploitation of ambiguities of meaning figures prominently in it. Therefore, one good reason for detecting cases of homonymy is to prevent someone else (or even ourselves, if we are not careful) from deceiving us in argument.
Non-coincidental homonymy. We can call caseslike the above coincidental or accidental homonyms Do all cases of homonymy meet this description? Consider these examples:
Any definition we supply for 'healthy' as it applies to Socrates will likely be nonsensical when applied to Socrates' diet, and conversely. Nevertheless, these cases are not merely coincidentally related, since both are connected with what it is to be healthy for a human being. Socrates is healthy because the definition of 'healthy' applies to him; his diet is healthy because it is the sort of diet which tends to sustain and improve his health. We can easily find hosts of other cases like this, in which things appear to be homonymous but not just accidentally so.
As it happens, among these cases are some of crucial importance to Aristotle's views on metaphysics and on ethics. Most prominently, he considers 'being' and 'good' to apply to things homonymously, but not coincidentally so. To see how, we need to explore the territory between plain synonymy and coincidental homonymy.
A good place to start is with Aristotle's classifications of entities. One such classification occurs early in the Categories. At 1a20-b9, Aristotle divides up all 'things that are' into four classes, according as they do or do not have either of two properties: being predicated of a subject and being present in a subject
To be predicated of, or said of, a subject is to be of such a nature as to be applied to many things (cf. Int. 17a38-b1). Aristotle calls a thing with this property universal (kath'holou: 'of a whole'), and he calls a thing without it particular (kath' hekaston: 'according to each'). For example, Socrates is a particular and man is a universal.
To be present in a subject is to exist in something in such a way as not to be capable of existing apart from it (Cat. 1a24-25). For instance, colors cannot exist except as the colors of physical objects. Those objects which are not present in a subject are those Aristotle describes as substances or 'thises.' For instance, Socrates is not present in a subject, though Socrates' color is.
These two characteristics are independent, that is, either may be present or absent in a thing. Since everything must either have or fail to have either characteristic, there are just four types of thing, as given in the table below:
|THINGS THAT ARE:||Not predicated of a subject
|Predicated of a subject
|Not present in a subject
|Primary substance: Socrates||Secondary substance: human, animal|
|Present in a subject
|Particular non-substance: Socrates' knowledge of how to read and write||Universal non-substance: knowledge|
This classification of entities is closely related to the more famous division into the categories. In order to see just how, we need first to take a side trip through Aristotle's views on the meanings of words.
Following Plato, Aristotle distinguishes between meaningfulness and truth. For him, only articulate sentences are susceptible of being true or false. Individual words may be meaningful, but truth and falsehood only arise in combination.
This is an important distinction to make, since it permits Aristotle to solve an old puzzle about the impossibility of false utterances. However, its greatest importance for us just now is in its details. Aristotle has quite definite views on how words may be combined to make sentences and on what their meanings may be. Words take their meanings from the things they designate, and therefore any classification of things will imply a corresponding classification of words. The distinction made above, for instance, lets us separate words as well as things into universal versus individual. Universal words are those which can be predicated of a subject (word), that is, can appear as the predicates of sentences. Individual or particular words, by contrast, can never really be predicated of any subject.
Likewise, the distinction between things which are and things which are not present in a subject gives rise to a corresponding distinction of words. However, Aristotle expands this twofold division into a more complicated classification of kinds of predications (genê tôn katêgoriôn: the word 'category' is derived from the Greek katêgoria, 'predication'). In the Categories and in Topics I.9, this classification is presented in greatest detail, with ten divisions:
|Name||In Greek . . .||. . . Literally||Aristotle's examples|
what it is
this something here
|Socrates, a particular horse, man, horse, animal|
|Quantity||poion||how much||2-foot, 3-foot|
|Quality||poion||what kind||white, literate|
|Relation||pros ti||with respect to what||double, half|
|Place||pou||where||in the marketplace|
|Time||pote||when||yesterday, last year|
|Position||keisthai||to be put, to lie||is sitting, is lying down|
|Possession||echein||to have||is shod, is armed|
|Action||poiein||to do||to burn|
|Passion||paschein||to undergo||to be burned|
Aristotle refers to and uses this division many times, but only in the Categories and Topics do we find ten. Elsewhere, there may be eight, or six, or five, or even four. In every case, however, one critical point is clear: not all categories are equal. The distinction between substance and all the other categories is much more significant than the distinctions among the non-substance categories. In fact, it corresponds to the distinction between what is not, and what is, present in a subject.
Since the categories are fundamentally different kinds of thing, nothing in one category can be the same as anything in another category. This much may seem obvious. However, what is not obvious, and what is equally important for Aristotle, is that when A and B belong to the same category, A can express 'what B is'. For instance, Socrates, human, and animal are all substances, and it is true to predicate animal of human and human of Socrates. Aristotle describes these predications as saying what the subject is.
The relationship between predicate and subject in a true same-category predication has certain properties.
In a case such as this, Aristotle describes the predicate as saying what the subject is.
Contrasted with these are cross-categorial predications, with subjects and predicates from different categories. In 'Socrates is pale', for instance, the subject is a substance and the predicate is a quality. Since the definition of a quality cannot apply to a substance, this predication cannot be synonymous: from the fact that Socrates is pale, it does not follow (and indeed it cannot be true) that the definition of pale applies to Socrates. Similarly, cross-categorial predications are not transitive. Thus, though Socrates is pale and pale is a color, it does not follow that Socrates is a color.
From the standpoint of modern (post-Fregean) logic, this contrast seems to make little sense. A Fregean analysis of 'Socrates is pale' decomposes it into a proper name, 'Socrates', and an incomplete expression 'is pale' which becomes a statement when an appropriate number of arguments is supplied (in this case, one). The meaning of 'Socrates' is that which it names, Socrates. The meaning of 'is pale' is the class of objects to which it applies. The sentence is true if and only if the object named by 'Socrates' is a member of the class named by 'is pale.'
Exactly the same form of analysis applies to 'Socrates is a man': it is true if and only if the object designated by 'Socrates' is a member of the class of objects satisfying '___is a man'.
Aristotle approaches this matter differently. He regards 'pale' as designating, not the class of pale things, but paleness. That is to say, 'paleness' is a name of paleness in the same way that 'Socrates' is a name of Socrates. The difference between Socrates and paleness (and therefore between 'Socrates' and 'paleness') is a categorial one: Socrates is a substance, whereas paleness is a quality. Now, Aristotle notes that we do not say 'Socrates is paleness' but 'Socrates is pale'. He calls this a matter of paronomy, 'naming after': pale things are named 'pale' because they are named after paleness.
Since paleness and Socrates are categorially different, Socrates cannot be paleness. He can, however, have paleness, that is, paleness can be present in him as a subject. When that is the case, then Socrates is paronymously called 'pale' after paleness. To reflect this distinction, Paul Grice and Alan Code have proposed calling the two types of predication izzing and hazzing respectively: if Socrates izz a human and an animal, whereas he hazz paleness.
To summarize this in a table:
|Subject and predicate in the same category||Subject and predicate in different categories|
|Predicate says what subject is||Predicate says what subject has|
|Subject and predicate are synonymous||Subject is paronymous with|
|Whatever is said of the predicate is said of the subject||What is said of the predicate cannot be said of the subject|
|Definition of the predicate applies to the subject||Definition of the predicate does not apply to the subject|
In fact, matters are more complicated than this. The twofold distinction between izzing and hazzing gets complicated by the categories in a manner exactly analogous to the distinction between what is not and what is present in a subject. Thispassage from Topics I.9 gives Aristotle's view:
It is clear at once that an <expression> signifying the what-it-is will sometimes signify a substance, sometimes a quantity, sometimes a quality, and sometimes one of the other categories. For, supposing the example under consideration is a man, if it says that the example is a human or an animal, then it says what it is and signifies a substance. On the other hand, supposing the example under consideration is a white color, if it says that the subject is a white or a color, then it says what it is and signifies a quality. Similarly, supposing that the example under consideration is a foot-long length, if it says that the example is a foot-long length, then it says what it is and signifies a quantity. And likewise with the other <categories>. For any of these, both in the case in which the same thing is said about itself and in the case in which its genus is said about it, signifies what it is. But when it is said about another <category>, then it does not signify what it is, but how much or what sort or one of the other categories. (Top. 103b27-39)
Here, Aristotle is using the categories for a third purpose. In addition to classifying things and words, they also classify predications, that is, relationships expressed by the predication of one term of another. One relationship, 'saying what something is,' applies to all same-category predications. The other relationship, however, has no single name. Instead, it takes as many forms as there are non-substance categories.
This table summarizes the relationship of predicate to subject in various predications:
|synonymous, says what subject is||paronymous, says what subject has (relationship is given by category of predicate)|
|(not a genuine predication)||synonymous and says what subject is, if both are in same category|
Coming soon: Homonymy and the Science of Being as Being