Brian Schwartz

Ancient Philosophy Seminar, Spring 1997, Swarthmore College

Essence in Aristotle's Categories and Metaphysics: Is it Epistemological or Metaphysical?

When I first read Aristotle's Categories, I experienced the pleasure of recognizing my own ideas in his, and being able to integrate his ideas into my own. Yet, when I began Metaphysics VII, I did not understand what motivated Aristotle to explore the issues brought up in the work. What struck me most was how his notion of primary substance in Metaphysics VII differed from the relatively simple one he related in the Categories. The main difference is the Metaphysics involves the use of matter and form in relation to primary substances. The purpose of this paper is to explore what philosophical issues motivated Aristotle to change, and perhaps abandon, his view on primary substance as described in the Categories.

Primary Substance: Categories

In Aristotle's Categories, the term primary substance is nearly1 equivalent to what we call proper nouns, and the term secondary substance refers to what we commonly call nouns. Formally, Aristotle defines a primary substance as something that is "neither said of any subject nor in any subject" (1a15). "Further, the primary substances are subjects for all the other things, and all the other things are predicated of them or are in them; this is why they, most of all, are called substances" (2b15). "A feature common to every substance is not being in a subject; for a primary substance is neither said of nor in a subject" (3a9).

If x is to be said of a subject, x's name and account must be predicated of the subject. For example, in the statement: Jerry Seinfeld is a comedian, Jerry Seinfeld is the primary substance, and a secondary substance, comedian, is said of him. Jerry Seinfeld can be categorized as a comedian. Since he can be categorized as an entertainer and as a man, entertainer and man are both secondary substances. As Aristotle writes:

"[A]fter the primary substances, only their species and genera are said to be secondary substances; for they are the only things predicated that reveal the primary substance" (2b30). "The species in which the things primarily called substances belong are called secondary substances, and so are their genera" (1b15).

Primary substances are "individual and numerically one" (3b10). Jerry Seinfeld is a primary substance because he is unique. He is one of the things people talk about when they speak of men, entertainers, or comedians (3a35). Yet, as a primary substance, Jerry Seinfeld is not a genera of anything else. He can not be said of or in anything.

Aristotle writes that "if something is in a subject, in most cases neither its name nor its account is predicated of the subject. In some cases the name may well be predicated of the subject, but the account still cannot be predicated" (2a20ff). For example, in the statement: Jerry Seinfeld is funny, funny is said in Jerry Seinfeld. This statement can be rephrased as: Jerry Seinfeld is a funny person, where funny person is said of Seinfeld. In terms of Aristotle's ten categories, funny is a quality as are "white" and grammatical," while comedian, entertainer are substances as are "man" and "horse."

Only secondary substances are said of substances, while nonsubstances are said in substances. The nonsubstance categories are quantity, quality, relative, where, when, being is a position, having, acting on, and being effected. I will call nonsubstances attributes. Each of them describes the substance being predicated upon, but are not secondary substances because they are not genera of the substance.

Aristotle makes a metaphysical claim with his distinction between saying things of and in subjects. To make clear the difference between predicating a substance rather than an attribute on something, i.e., saying is of or in something else, we must look at the relationship between substances and attributes. Aristotle writes:

"All other things [that are not primary substances] are either said of the primary substances as subjects or in them as subjects. This is evident if we examine particular cases. Animal, for instance, is predicated of man, and so also of an individual man; for if it is not predicated of any individual man; neither is it predicated of man at all. Again, color is in body, and so also in an individual body; for if it is not in any of the particular bodies, neither is it in body at all.

"...If, then, the primary subjects did not exist, neither could any of the other things exist. For all other things are either said of these as subjects or are in these as subjects, so that if the primary substances did not exist, neither could any of the other things exist" (2a35ff).

This is an explicitly anti-Platonic metaphysical view. Plato categorizes things as either universals (forms) and particulars, and for him, if the forms did not exist, the particulars could not exist. For Aristotle, primary substances are "ontologically prior" to all secondary substances that can be said of them, and all nonsubstances that can be said in them. Further, Aristotle differentiates between secondary substances and nonsubstances, while Plato speaks of forms (of attributes) such as beauty, piety, and equality as if they were substances, i.e., he predicates upon them.

As Meinwald (1992) writes, Plato's predications upon what Aristotle calls nonsubstances are self-predication statements, which are defined by their form: X is in itself X. For Plato, the form of beauty, piety, or equality is "in itself" beautiful, pious, or equal. While Plato does not articulate what such statements mean, Meinwald regards them as "self-predicating tree statements." A "other-predicating tree statement" is what Aristotle would call a predication of a genus onto a species. These predications say that the subject can be categorized as the substance predicated upon it. For example, the statement "Comedians are people" indicates that a comedian is a type of person, while other types in this categorization scheme are other professions people might have. The "tree" is shown below.

People

/ \

comedians non-comedians

/ \

Jerry Seinfeld, Dennis Miller Bill Gates, Tibor Machan

While Plato might say that Seinfeld and Miller "partake in the form of" comedian and man, "other-predication" statements need not contain any Platonism. They just as easily apply to Aristotle's Categories as they do Plato's metaphysics. Further, they correspond to how people really speak of things. Meinwald even appeals to common sense when she says the predication "Cathood has vertebrae" means that the category "cats" is a differentia of the genus "organisms with vertebrae." Clearly only particular cats have vertebrae, she says.

Yet, self-predication statements are foreign to our everyday language. For example, instead of categorizing people by their occupation, let's change the middle tier of the above tree to the attributes (for Aristotle) "Large" and "Small." For Plato, the form of large, Large, is in itself large, and Small is in itself small. By extension of Meinwald's cathood example, only particulars are large or small, where for simplicity we define our terms by an arbitrary volume, say, 10 cm3. Meinwald writes that self-predicating tree-statements "exemplify the limit case of predication of a subject in relation to itself: It is uninformative but safe" (380). "Self predication sentences will always be true when they are used to make tree predications" (M 385). Since she never says what these statements actually mean, I can not conclude whether she has succeeded in showing (what I call) attributes to be substances. The burden of proof is on her.

Secondary substances, the genera of particulars, signify "a sort of thing," and it is these things people are talking about when they predicate upon secondary substances (3b15). By defining his categories by how things are said, by people, Aristotle has tied the metaphysics implied by the categories to epistemology. People will categorize different particulars as the same secondary substance, says Aristotle, if they have the same essence (ousia). Man and ox (i.e., all individual human beings and oxen) are called animals, says Aristotle, because they have "the same account of the essence." "For if one gives an account of each, saying what being an animal is for each of them [people and oxen], one will give the same account (logos)" (1a6ff). So to give an account a particular thing's essence is to identify what it is about that the particular that makes it the type of thing that it is.2 In this case, the essence of people and oxen are the same, i.e., each are animals for the same reason (account). Aristotle does not say what this reason is. By saying so little about essence in the Categories, Aristotle does not tell what determines how people comes to classify things together. Due to limited textual evidence, we can not conclude that the account is a shared characteristic or attribute (nonsubstance) of the primary substances.

The ontological dependence, if any, of primary substances on attributes is another unresolved issue in the Categories. Aristotle differentiates primary substances from secondary substances and attributes with a negative predication: that they are neither said of or in anything (1a15, 2b15). He has said what they are not, but has said only that they are "individual and numerically one" (3b10).

Another attribute for substances is that they "receive contraries" by changes in themselves. Aristotle appeals to experience to assert this, as he can not think of any non-substances that can receive contraries, but the only things that can receive them are primary substances:

• if a table, a secondary substance, is defined by a planar surface elevated by things below it that leave room for stuff under it receives the contrary of becoming a big block, then it is no longer a table.

• if X, a quality, is defined as the property of being pale, and it receives the contrary of not being pale, it is no longer X.

• I, a primary substance, receive the contrary of not being pale, I am still me, no matter what they do or say (3b10ff, 4a10, 4b18).

The burden of proof is on those who try to find non-primary substances that can receive contraries. This is not an appeal to ignorance, i.e., we can't prove it false, so it's true. We have reason to think A.'s claim about substances is true, and no reason to think it is false.

Before I move on to discuss Aristotle's notion of primary substance in the Metaphysics, let's review what he says about it in the Categories:

1. A primary substance is never said of or in something, rather things are said of or in it.

2. A primary substance is "individual and numerically one."

3. Only primary substances can "receive contraries" and still be what they are.

Substance: Metaphysics

Aristotle devotes Metaphysics IV to the study "being insofar as it is being, and also the properties of being in its own right." As a science, metaphysics concerns itself with being in general, whereas the "special sciences" consider certain aspects of things. Just as chemistry concerns itself with things insofar as atoms react to form molecules, and biology concerns itself things insofar as they are alive, metaphysics concerns itself with things insofar as they are as they are beings (1003a21, b15). Aristotle still has in mind the categories, as he writes that

"[B]eing is spoken of in many ways, but in all cases it is spoken of with reference to one principle (arché). For some things are called beings because they are substances, others because they are attributes of substance (ousia), others because they are a road to substance, or because they are perishings or privations or qualities of substance, or productive or generative of substance or of things spoken of with reference to it, or because they are negations of one of these or of substance. This is why we also say that not being is-i.e., is not being" (Met. 1003b5).

Aristotle categorizes beings as substance or things that exist in relation to substance. These relations are attributes, perishings, privations, qualities, etc. of substances. According to Irwin and Fine (1995), "principle" in this context is the beginning or origin, as a seed might be the principle of a plant (Met. 1072b33). He continues:

"In every case the dominant concern of a science is with its primary object, the one which the others depend and because of which they are spoken of as they are. If, then, this primary object is substance, the philosopher must grasp the principles and causes of these substances" (1003b18).

With the conditional "If" above, Aristotle appears to have retreated from his assertion in the Categories that if "the primary subjects did not exist, neither could any of the other things exist" (Cat. 2a35ff). He has also introduced a new idea the substances have "principles" and "causes." What this means is not immediately clear.

The first thing Aristotle says about being is that being and unity are "the same and a single nature" (Met. 1003b23). He illustrates this point by stating that "[one man] is the same as a [man], and moreover a [man who is] is the same as a [man]" (1003b27, brackets added). The first part equates the determiner "a" with "one" which calls attention to the function of the determiner "a," which is to signify one thing. The second part says that to be a man is the same as to be a man who is, which generalizes, substituting "something that" for "man who," to:

[something that is] = [something].

This formulation implies that

[to be something that is] = [to be something],

where I have added "to be" to the right side of each phrase. Replacing "is" with "exists," we have:

[to be something that exists] = [to be something].

Separating the verbs on the right we have

[to exist + to be something] = [to be something].

Here, Aristotle claims that to exist is not merely to be, but to be something, a certain specific thing. That something exists means that it is something, or in my terms, to have an identity. For Aristotle, according to my interpretation of (1003b27), existence (to be) and identity (to be something) are inseparable.

Aristotle makes my conclusion more explicit in Book V, when he tells how things are said to be "in their own right." By noting that "being signifies the same as each of these [predications involving the categories]" (1017b26). So, to be is to be something, where something belongs to one of the categories. Note that being one "something" often, if not always, necessitates that [what is that something] is also something else. For example, a green thing must be material for it to reflect green light, as only materials reflect, and a thing is green only if it reflects green light.

To the above passage about the equivalence of being and unity, Aristotle adds that "the substance of a thing is noncoincidentally one thing; and similarly it is essentially some being" (1003b33). Apostle (1966) notes that "substance" here refers to "the substance of a thing in any category. In this way, also a color would be a being and one. The substance of a thing is the cause of its unity; for example, the soul in the case of a man." "Matter, for example, being indefinite and without form, would not be one or a being if it were not for the form or substance which is with it, so to say." At this point, Apostle's interpretation needs more textual support than that which he footnotes (it comes later in Book V.8). I find it significant that the use of term "substance" as "substance of a thing" did not appear in the Categories, where substance was a type of thing, rather than what a thing (may) possess.

Substance in the Metaphysics is not only what something has (rather than just a type of being as it was in the Categories), but something that can be signified, or spoken of:

"For, as we saw, one thing is signified, and this is the substance of something. Now, to signify a thing's substance is to signify that being that thing is nothing other" (1007a25).

So to talk about something is to talk about its substance. Further, to be something is "nothing other" than being the substance of that something. Recall from the Categories that man and ox are both animals because they have the same essence (Cat. 1a6ff). If, by (Met. 1007a25), [to be an animal] is [to be the substance of an animal], and what we call animals are animals because they have "the same account of the essence," then the essence of a particular animal (primary substance) is the substance of an animal.

So in general, the essence of a primary substance is the substance of the secondary substance that is predicated upon it. According to Apostle nonsubstances (like color) can have essences, since they can have a substance. Just as we call an ox an animal because its essence is the substance of animal, we call green a color because its essence is the substance of color.3 In both cases, what Aristotle means by the essence of an secondary substance is not yet clear at this point on the Metaphysics, Book IV.

Book V may clear up some confusion, as Aristotle distinguishes between two ways to talking about being. Being is spoken of "coincidentally," which is to predicate something, either a secondary substance or an attribute, upon a secondary substance that into which a primary substance can be categorized. For example, "The musician is pale," predicates "pale" on a person who happens to be a musician. Being a musician and being pale coincide on the same person.

Things are also said to be "in their own right." These things are

"signified by the types of predication; for they are said to be in as many ways as there are ways of signifying a being. Among the things predicated, some signify what-it-is, some quality, some relative, some acting, some being acted on, some where, some when, and so being signifies the same as each of these. For there is no difference between 'a man is flourishing' and 'a man flourishes', or between 'a man is walking (or cutting) and 'a man walks (or cuts)', and the same is true in the other cases" (1017a23ff).

Aristotle has clearly enumerated the types of being (except for "quantity," "being in a position," and "having") he introduced in the Categories. This distinction does not appear valid, as saying that "the musician is pale" is to predicate a quality (pale) on a secondary substance, musician. It can only make sense if predicating what something is "in its own right" is to predicate its essence, i.e., what makes the thing what it is (called). Aristotle states this explicitly later in the Metaphysics: "[I]n the case of primary things, those spoken of in their own right, a thing and its essence are one in the same" (1032a6ff).4

Aristotle states explicitly what he regards as substance Metaphysics V.8. Before I review this chapter, I will extract what he has said about substance thus far in the Metaphysics. While there exist substances and things that exist in relation to them (1072b33), substance is not necessarily a primary object. A primary object is "the one which the others depend and because of which they are spoken of as they are. If, then, this primary object is substance, the philosopher must grasp the principles and causes of these substances" (1003b18). As noted above, primary substances appeared to be primary objects in the Categories. Yet Aristotle may be searching for something else that is the primary object.

Metaphysics V.8 begins with a return to the notion of (primary) substances spoken of in the Categories. They "are said to be substances because they are not said of a subject, but the other things are said of them" (1017b12). Aristotle introduces "another way" things are called substances. Such substances, "by being present in things that are not said of a subject, is the cause of their being-for instance, the soul for an animal-is called substance" (1017b15). It is now clear what Aristotle means by the substance of a thing: it is what makes a thing what it is. Since the a being must be something, as shown above, its substance determines what that something is.

Recall Aristotle's explanation of why people categorize different particulars as the same secondary substance: they have the same essence (Cat. 1a6ff). The essence of a primary substance is what it is about that the particular that makes it the type of thing that it is. In the above passage from the Metaphysics, Aristotle identifies essence with a use of the term substance.

Before concluding that "substance is spoken of in two ways," Aristotle claims that

"the parts present in such things, defining them and signifying a this, the things whose destruction the whole is destroyed, are called substances...Further, the essence, whose account is the definition, is also said to be the substance of a thing...[Substance] is both the ultimate object, which is no longer said of anything else, and whatever, being a this, is also separable-this is true of the shape, i.e., the form (morphé), of a thing" (1017b18-26).

So the two things Aristotle means by the term "substance" are:

• substance1: primary substances: "the ultimate object," particular individual things, as spoken of in the Categories.

• substance2: Essence: the thing which makes a primary substance what it is and whose account is a definition. The essence of a thing Aristotle calls the form of a thing.

With his concept of essence, Aristotle has appears to have retreated from his position in the Categories that if "primary subjects did not exist, neither could any of the other things exist" (2a35ff). He calls primary substances the "ultimate objects," but attributes essence or form to be "the cause of their being" (1017b15).

His example of a primary substance, an individual organism, illustrates his point. The thing would not be an organism without its substance of form: its soul. In De Anima II.1 (412b), Aristotle defines the soul of a organism to be its function of its matter, the material the primary substance consists of. Hence, an organism's soul is its biological functions, without which it would be dead, i.e., not what it is: an organism.

Yet, does Aristotle mean that essence and form of a primary substance is (a) the cause its being, or (b) the cause people's naming it as they do? In (a), essence is metaphysical, and this position is at odds with the one Aristotle takes in the Categories, namely that primary substances are just that, primary, and that nothing is ontologically prior to them. In (b), essence is epistemological, and the essence of something is the attribute of it people use to define it and differentiate it from and with other things. If (b) the case, then Aristotle's metaphysics in the Metaphysics is consistent and complimentary to that of the Categories. Metaphysics VII makes clear which position Aristotle takes.

Aristotle introduces the term "separable" as an attribute of essence at the end of Book V, above. He elaborates on this concept in Book VII, where he claims that "substance is primary in every way: in nature, in account, and in knowledge. For none of the other things predicated is separable, but only substance" (1028a33). Earlier in Book VII he writes that walking, flourishing and sitting do not exist "in their own right not is any of them capable of being separated from substance, but it is more true that the walking or sitting or flourishing things is a being (if indeed it is a being). This latter type of thing is apparently more of a being because it has some definite subject-the substance and the particular-which is discerned in such a predication" (1028a21ff). If by "separable," Aristotle means separable from substance, as he writes above, what can it mean for substance to be separable from substance, as he writes of essence and form in Book V.8 (1017b18-26)? Since something can not be separated from itself, Aristotle means that the essence of a primary substance is separable from the primary substance. The question still remains whether Aristotle means "separable" to be metaphysical or epistemological.

At this point Aristotle states that the "old question...'What is being?' is just the question 'What is substance?'" (1028b3). It is not clear whether Aristotle is speaking of substance1 or substance2.

Aristotle answers this question by investigating the primary subject. Since "subject is that of which the other things are said, but which is not itself in turn said of any other thing," "the primary subject seems to be substance most of all" (1029a1ff). Primary subjects then are, or at least resemble, the primary substances introduced in the Categories. Thus far he is talking about substance1.

Yet, primary subjects are spoken of in three ways: the matter (hulé), the form, and the compound of matter and form. His now canonical example to illustrate these concepts is a bronze statue, a compound with "figure and character" as form and bronze as matter.5 Aristotle has already identified the form to be the essence and a substance (1017b18-26), and his example illustrates it: The compound is a statue (or at least we call it a statue) rather than an ashtray (made of bronze) because of the compound's form. Note that the primary substances introduced in the Categories are what Aristotle calls "composites" in the Metaphysics. Which of the three, matter, form, and composite, is substance, i.e., "is not said of a subject but has other things said of it"?

Aristotle first considers matter. He concludes at a point that matter is the only substance because "affections, products, and potentialities of bodies" are "abstracted" or "removed," nothing is left, except for "what is determined by these," the matter (1029a10-20). The attributes "determine" the matter because matter is "spoken of in its own right neither as being something, not as having some quantity, not as having any of the other things by which being is determined" (1029a20). Yet, because matter exists, but is not something, or "a this," it can not be substance, "[f]or being separable and being a this seem to belong to substance most of all" (1029a28). After rejecting matter as substance, Aristotle considers form and compounds to be substances. He rejects compounds as substances because they are "posterior to the other two," matter and form, and considers form as substance. In other words, compounds qualify as substance1, but not as substance2. Aristotle has thus stated explicitly that there exists something ontologically prior to compounds, i.e., the primary substances spoken of in the Categories.

Aristotle is mistaken in assigning matter and form ontological priority to compounds. Just because we can look at particulars in terms of their matter and form does not mean that they are posterior to the matter and form. Further, the matter and form are posterior to particulars. As Aristotle said of matter, it is not "a this" unless form can be predicated upon it. Bronze, for example, exists and we can talk about its properties, e.g., its melting point, but all bronze that exists in some shape or form-regardless our ability to describe the form mathematically. Yet, the same goes for form. We can speak of spheres and souls, but only spheres made of a particular matter and souls that are particular bodily functions exist in reality. Further, matter and form can be predicated upon each other: The hunk of bronze is a sphere; The sphere is made of bronze. No form is separable from its matter, and no matter is separable from its form.

We can avoid the complexity of Metaphysics VII if we remember that to exist is to be something (1003b27). Recall that in the Categories, A. states that if "primary subjects did not exist, neither could any of the other things exist" (2a35ff). These other things that could not exist is what the primary substances are: attributes. Aristotle showed that by stripping off the attributes of a compound we are left with nothing (1029a10-20). This shows that if the attributes did not exist, the primary substance would not either, as it would somehow exist, but not be "a this." A primary substance is not some sort of thing with no attributes, like some sort of bare existent. It is a compound.

Aristotle's criterion for rejecting matter as substance, "being separable and being a this" (1029a28), is impossible to satisfy. By separable, Aristotle means that some substances are separable from attributes. An easy example is the attribute "sitting down," which is in Aristotle's "being in a position" category. I can be sitting or not sitting and still be what I am. Yet, consider the attribute "rational." If I ceased to be that, I would cease to be what I am, a human being. In Aristotle's terms (1017a), I am sitting or standing coincidentally, but rational in my own right. Hence, rationality would be my essence, and since I am a primary substance, it is what defines me as a human being (1030a5ff). I am not separable from being rational because my rationality explains many of my other characteristics. As Aristotle writes "the account of a thing's essence is the account that describes but does not mention the thing" (1029b20). If I were not rational, I would not be "a this." Since to be (exist) is to be something, an existent can not be separated from its attributes, as being certain attributes is precisely what "being a this" is.

I believe much of the above difficulties can be cleared up if we view essence as epistemological rather than metaphysical. Aristotle has been trying to explain how people come to classify primary subjects into the same secondary subject category, for example, how and why we classify both people and oxen as animals. His answer is that people and oxen have the same essence, and this essence is the cause of people's and oxen's being animals, as opposed to something else.

Problems arise because for Aristotle, because a thing's essence is also its form (1017b26). Yet, people predicate different secondary substances onto the same composites (primary substances, particulars). For each predication of a different secondary substance upon a primary substance, there must be a corresponding essence the primary substance has. Yet, since a thing's essence is what it is in its own right (1029b15), a thing can only have one essence.

Consider the following scenario. An assassin is in hiding in the home of his victim. The victim, feeling safe, wants to write in his journal, and is looking for his favorite pen, a 1953 Waterman. The burglar want to murder this man, but stupidly forgot a weapon. They both spot the shiny pen sitting on the rolltop desk and construct the following trees:

Assassin Victim

Everything Everything

/ \ / \

~ weapons weapons writing utensils ~writing utensils

/ \ / \

blunt objects sharp objects pens ~ pens

\ /

the 1953 Waterman

For Aristotle, the particular pen shares an essence with the other pens (Victim's tree) and shares an essence with other sharp objects. Since "essences will belong only to species of a genus and to nothing else" (1030a13), and the particular "pen" is a species of the genus "sharp objects" and "pens," my example fits the above criterion for essences.

One might object to this example because the 1953 Waterman really is a type of pen, and that the above trees predicate coincident attributes onto the primary substance that need not apply to the thing for it to be what it is "in its own right." Such an objection is based on the premise that I am trying to refute: that essence is metaphysical.

In a sense, even Aristotle says essences are not metaphysical because he defines things by their function:

"a proper definition of each part [of a body] requires reference to its function...For a hand is not part of a man in just any condition, but only when it is capable of fulfilling its function" (1035a17, 1036b25-33).

In my example, the function of the "pen" is, for the collector, something to write with, and for the assassin, a weapon. In general, the functions of things are not intrinsic to them, but are based on the people's context., which determines how they will categorize a particular thing and declare what the thing is. My argument is as follows:

1. The essence of a particular makes the thing what it is.

2. To give an account of the essence is to give a definition.

3. A proper definition of a thing refers to its function.

4. The function of something depends on a person's context.

5. By (4), definitions are contextual, and by (2), essence is contextual.

Conclusion

In the Categories, he does not explain how people categorized things into the same genus, but just says that the particulars grouped together had the same "essence." Rather than claiming, as Plato does, that such particulars partake in something other-worldly i.e., the Forms, Aristotle claimed that they possessed essences, which were the "form" of the particular thing. Yet Aristotle's essences function as Plato's Forms do: they make particulars what they are, i.e. are the cause of a particular's "being a this," rather than "being a that," and are ontologically prior to the existence of particulars.

I have argued that essences are not prior to particulars, nor are they a metaphysically special attribute of things that make the things what they are. Rather, in the tradition of Aristotle's appealing to how we speak and his use of functional definitions, I have concluded that essences and the ways people categorize things depend on their context.

Beyond the scope of this paper is how people to categorize things when all attributes of things are on the same "metaphysical level." It has been argued by myself in previous papers and by Rand (1979), Kelley (1984), and Edelman (1992), that people categorize according to what is valuable to them and by grouping things as less different from each other than they are from a third thing.

Notes

1 Proper nouns are primary substances, but so are particular nouns like "this x," where x is a noun, e.g., tree. Primary substances, as described later, are "being a this."

2 Aristotle is not clear as to whether he means a thing's essence determines what it is metaphysically, or how people categorize it. Perhaps these is no difference for him. This issue will acome up later.

3 Again, whether essence makes a thing what it is (essence as metaphysical), or its the cause of our categorizing it as we do (essence as epsitemological) , or both, is not yet clear.

4 I have found making this distinction between predicating essentials and coincidences useful when trying to understand other people's ideas.

5 A more general notion of matter is given in Met. I.3, where the substance remianig throughout but changing in respect to its attributes...it persists in every change. (983b10)