## 1. The Four-Fold Division



The *Categories* divides naturally into three distinct parts
-- what have come to be known as the *Pre-Predicamenta*
(chs.1-4), the *Predicamenta* (chs. 5-9), and the
*Post-Predicamenta* (chs. 10-15). (These section titles reflect
the traditional Latin title of the entire work, the
*Predicamenta*.) In the *Pre-Predicamenta*, Aristotle
discusses a number of semantic relations (1a1-16), gives a
division of beings (ta onta), into four
kinds (1a20-1b9), and then presents his canonical list of ten
categories (1b25-2a4). In the *Predicamenta,* Aristotle
discusses in detail the categories of substance (2a12-4b19),
quantity (4b20-6a36), relatives (6a37-8b24), and quality
(8b25-11a39), and provides a cursory treatment of the other
categories (11b1-14). And finally, in the
*Post-Predicamenta*, he discusses a number of concepts relating
to modes of opposition (11b15-14A25), priority and simultaneity
(14a26-15a13), motion (15a14-15b17), and ends with a brief
discussion of having (15b18-31). There is considerable debate
about whether Aristotle thought all three parts belong to a single
work, and if he did, why he thought they are all needed for the work
to be a unified whole. There is nonetheless widespread agreement that
at the very heart of the *Categories* are two systems of
classification, one given in the *Pre-Predicamenta*, and the
other in the *Predicament*a.



Aristotle's first system of classification is of beings,
(ta onta) (1a20). The division proceeds
by way of two concepts: (1) said-of and (2) present-in. Any being,
according to Aristotle, is either said-of another or is not said-of
another. Likewise, any being is either present-in another or is not
present-in another. Because these are technical notions, one would
expect Aristotle to have defined them. Unfortunately, he does not
define the said-of relation; and his definition of the present-in
relation is either circular or rests on an undefined concept of being
in. He says: 'By "present in a subject" I mean what
is in something, not as a part, and cannot exist separately from what
it is in' (1a24-5). Notice that the word 'in'
occurs in this definition of present-in. So, either 'in'
means the same as 'present-in', in which case the
definition is circular; or 'in' is itself in need of a
definition, which Aristotle does not give. Hence, Aristotle's
first system of classification rests on technical concepts whose
precise characterization is not settled by anything Aristotle
says.



Despite the lack of helpful definitions of these two concepts, there
is a fairly straightforward, though certainly not uncontroversial,
characterization of them that many scholars have adopted. By focusing
on Aristotle's illustrations, most scholars conclude that beings
that are said-of others are universals, while those that are not
said-of others are particulars. Beings that are present-in others are
accidental, while those that are not present-in others are
non-accidental. Now, non-accidental beings that are universals are
most naturally described as essential, while non-accidental beings
that are particulars are best described simply as non-accidental. If
we put these possibilities together, we arrive at the following
four-fold system of classification: (1) accidental universals; (2)
essential universals; (3) accidental particulars; (4) non-accidental
particulars, or what Aristotle calls *primary substances*. This
system maps readily onto Aristotle's own terminology, given at
1a20: (1) Said-of and present-in: accidental universals; (2) Said-of
and not present-in: essential universals; (3) Not said-of and
present-in: accidental particulars; and (4) Not said-of and not
present-in: primary substances. A brief discussion of each of these
classes should suffice to bring out their general character.


### 1.1 Not Said-Of and Not Present-In



The pride of place in this classificatory scheme, according to
Aristotle, goes to those entities that are neither said-of nor
present-in anything. Such entities, Aristotle says, are primary
substances (2a11). Although he only gives a negative characterization
of primary substances in the *Categories* -- they are
*neither* said-of *nor* present-in -- the examples
of them that he provides allow us to form a more robust conception of
what a primary substance is supposed to be. His favorite examples are
an individual man and a horse (1a20, 2a11). So, it is natural to
interpret him as thinking that among primary substances are concrete
particulars that are members of natural kinds. Whether in the
*Categories* Aristotle intended to restrict the class of
primary substances to just members of natural kinds turns out to be
among the more controversial topics in Aristotle scholarship. But at
the very least, he seems to think that members of natural kinds
present enough of a paradigmatic case that he can use them as
examples.



Now, given the above interpretation of the said-of and present-in
relation, a primary substance is a particular that is non-accidental.
It must be admitted that it is difficult to say exactly what it means
to say that a particular is non-accidental. In highlighting the fact
that primary substances are not the sorts of beings that can be
accidents, Aristotle seems to be indicating both that they are not
predicated of anything accidentally and that they are not entities
that are manifestly temporary, accidentally characterized, or
artificially unified, such as Socrates-seated-in-a-chair. Similarly,
by treating them as not said-of anything, Aristotle draws attention to
the fact that primary substances are not predicated of anything
either. Rather, they are themselves essential unities, and indeed not
predicable at all. Beyond these few remarks, however, it is difficult
to say exactly, given only what is made explicit in the
Pre-predicamenta what a primary substance is. But this, one might
argue, is appropriate for a metaphysically fundamental entity --
we can say of it what it is not, but because it is so basic, we lack
the vocabulary to say in an informative way what it is. And indeed,
Aristotle thinks that primary substances are fundamental in this way
since he thinks that all other entities bear some type of asymmetric
dependence relation to primary substances (2a34-2b6).


### 1.2 Not Said-Of and Present-In



If we continue to understand the said-of and present-in distinctions
as I have characterized them, we will also find that Aristotle thinks
that in addition to particulars in the category of substance there are
accidental, or what we can now call *non-substantial*,
particulars. Aristotle's example of such an entity is an
individual piece of grammatical knowledge (1a25). Perhaps a more
intuitive example is the particular whiteness that some object has. If
there are non-substantial particulars, then Socrates' whiteness
is a numerically distinct particular from Plato's whiteness.
Contemporary metaphysicians might call such entities tropes, and such
a label is acceptable as long as one is careful not to expect
Aristotle's theory to resemble too much contemporary trope
theories. In the first instance, if Aristotle does accept the
existence of non-substantial particulars, he certainly does not think
that they can exist apart from primary substances -- indeed, it
is most natural to interpret Aristotle on this point as thinking that
a non-substantial particular is a dependent entity, individuated only
by reference to the primary substance that it is present in. Hence,
Socrates' whiteness cannot exist without Socrates. Moreover,
thinking of such entities as standing in a primitive relation of
resemblance to one another is quite foreign to Aristotle's way
of thinking. Nonetheless, if the present interpretation is correct,
Aristotle did accept what are appropriately called particularized
properties.


### 1.3 Said-Of and Not Present-In



Returning, then, to those beings that are not-present in other beings,
Aristotle thinks that in addition to primary substances, which are
particulars, there are secondary substances, which are universals
(2a11-a18). His example of such an entity is man (1a21), which,
according to the present interpretation, is a universal in the
category of substance. If we again accept the distinctions in question
as I have drawn them, we should interpret secondary substances as
essential characteristics of primary substances. Moreover, because
primary substances seem to be members of natural kinds, it is natural
to interpret secondary substances as the kinds to which primary
substances belong. If that is so, then Aristotle thinks that not only
are primary substances members of natural kinds but that they are
essentially characterized by the kinds to which they belong.


### 1.4 Said-Of and Present-In



Finally, a being is both said-of and present-in a primary substance if
it is an accidental universal. Aristotle's example of such an
entity is knowledge; but again, whiteness provides a somewhat more
intuitive example. The universal whiteness is said-of many primary
substances but is only accidental to them.


### 1.5 A Recent Debate



The way in which I have characterized the concepts of said-of and
present-in is, as I have said, natural and relatively straightforward.
Moreover, it was by far the orthodox interpretation amongst
Aristotle's Medieval interpreters. I would be remiss, however,
were I not to mention the recent debate started by G.E.L. Owen about
the said-of/present-in distinction (Owen, 1965a). According to Owen,
Aristotle did not accept the existence of non-substantial particulars.
Instead, Owen argues, a being that is not said-of but present-in
primary substances is an accidental universal of the lowest possible
generality. Hence, Owen denies that the said-of/not-said-of
distinction is one between universals and particulars. I shall not
discuss Owen's interpretation but shall simply note that it has
spawned a huge deal of scholarly attention. The interested reader can
find a discussion of these issues here:



> 
> Supplement on Nonsubstantial Particulars
>  for
>  Aristotle Metaphysics
> 


## 2. The Ten-Fold Division


### 2.1 General Discussion



After providing his first system of classification, Aristotle turns to
the *predicamenta* and presents a second, which ends up
occupying him for much of the remainder of the *Categories.*
Aristotle divides what he calls *ta legomena* (ta
legomena), i.e.
*things that are said*, into ten distinct kinds (1b25). Things
that are said according to Aristotle, are words (*De Int*
16a3), and so it is natural to interpret his second system as a
classification of words. And because the English word
'category' comes from the Greek word for
*predicate*, one might naturally think of the second system as
a classification of distinct types of linguistic predicates. There is,
however, considerable debate about the subject matter of the second
system of classification.



There are three reasons to think that Aristotle is not primarily
interested in words but rather in the objects in the world to which
words correspond. First, his locution *ta legomena* is in fact
ambiguous, as between 'things said'--where these
might or might not be words--and 'things spoken
of'--where these are more naturally taken to be things
referred to by means of words. Second, Aristotle's examples of
items belonging to the various categories are generally
extra-linguistic. For instance, his examples of substances are an
individual man and a horse. Third, Aristotle explicitly accepts a
doctrine of meaning according to which words conventionally signify
concepts, and concepts naturally signify objects in the world (*De
Int* 16a3). So, even if he is in some sense classifying words, it
is natural to view his classification as ultimately driven by concerns
about objects in the world to which our words correspond.



Those scholars dissatisfied with the linguistic interpretation of
Aristotle's second system of classification have moved in one of
several directions. Some have interpreted Aristotle as classifying
concepts. The objections raised against the linguistic interpretation,
however, can again be raised against the concept interpretation as
well. Other scholars have interpreted Aristotle as classifying
extra-linguistic and extra-conceptual reality. Finally, some scholars
have synthesized the linguistic and extra-linguistic interpretations
by interpreting Aristotle as classifying linguistic predicates *in
so far* as they are related to the world in semantically
significant ways. Although I think that this latter interpretation is
probably the one that best withstands close textual scrutiny, the
general character of the second system of classification is most
easily seen by focusing on the extra-linguistic interpretation. So, in
what follows, I shall simplify matters by talking as if
Aristotle's first classificatory system is really a
classification of extra-linguistic items; and I shall note places at
which such an interpretation faces difficulties.



What then is Aristotle's second classificatory system? Quite
simply, it is a list of the highest kinds, which are also known as
*categories*. That there are highest kinds (or perhaps that
there is one single highest kind) can be motivated by noticing the
fact that the ordinary objects of our experience fall into classes of
increasing generality. Consider, for instance, a maple tree. It is in
the first instance a maple and so belongs in a class with all and only
other maples. It is also, however, a tree and so belongs in a broader
class, namely the class of trees, whose extension is wider than the
class of maples. Continuing on, it is also a living thing and so
belongs in a class whose extension is wider still than the class of
trees. And so on. Now, once this basic pattern is before us, we can
ask the following question: does this increase in generality go on ad
infinitum or does it end at a class that is the most general possible?
Does it end, in other words, at a highest kind?



It might seem that the answer to this question is obvious: of course
there is a highest kind -- being. After all, someone might argue,
everything exists. So the class that contains all and only beings must
be the class with the greatest possible extension. In the
*Metaphysics*, however, Aristotle argues that being is not a
genus (998b23, 1059b31). According to Aristotle, every genus must be
differentiated by some differentia that falls outside that genus.
Hence, if being were a genus, it would have to be differentiated by a
differentia that fell outside of it. In other words, being would have
to be differentiated by some non-being, which, according to Aristotle,
is a metaphysical absurdity. Although he does not explicitly make this
claim, Aristotle's argument, if cogent, would generalize to any
proposal for a single highest kind. Hence, he does not think that
there is one single highest kind. Instead, he thinks that there are
ten: (1) substance; (2) quantity; (3) quality; (4) relatives; (5)
somewhere; (6) sometime; (7) being in a position; (8) having; (9)
acting; and (10) being acted upon (1b25-2a4). I shall discuss
the first four of these kinds in detail in a moment. But doing so will
take us into matters that, while interesting, nonetheless distract
from the general nature of the scheme. So I will first discuss some of
the general structures inherent in Aristotle's second system of
classification, and then proceed to a more detailed discussion.



In addition to positing ten highest kinds, Aristotle also has views
about the structure of such kinds. Each kind is differentiated into
species by some set of differentiae. In fact, the essence of any
species, according to Aristotle, consists in its genus and the
differentia that together with that genus defines the species. (It is
for this reason that the highest kinds are, strictly speaking,
indefinable -- because there is no genus above a highest kind,
one cannot define it in terms of its genus and a differentia.) Some of
the species in various categories are also genera -- they are, in
other words, differentiated into further species. But at some point,
there is a lowest species that is not further differentiated. Under
these species, we can suppose, fall the particulars that belong to
that species.



Now, if we accept the characterization of said-of and present-in that
I have given, we can see that Aristotle's two classificatory
systems can, so to speak, be laid on top of each other. The resulting
structure would look something like the following.



> 
> 
> 
> |  |  |
> | --- | --- |
> | Substance | Quantity  Relatives  Quality  ... |
> | Said-of
> 
> Not Present-In | Said-of
> 
> Present-In |
> | Not Said-of
> 
> Not Present-In | Not Said-of
> 
> Present-In |
> 
> 
> 



Some features of this system are worth pointing out. First, as I have
already noted, Aristotle gives pride of place in this scheme to
primary substances. He says that were primary substances not to exist
then no other entity would exist (2b6). As a result, Aristotle's
categorialism is firmly anti-Platonic. Whereas Plato treated the
abstract as more real than material particulars, in the
*Categories* Aristotle takes material particulars as
ontological bedrock -- to the extent that being a primary
substance makes something more real than anything else, entities such
as Socrates and a horse are the most real entities in
Aristotle's worldview. Moreover, among secondary substances,
those at a lower level of generality are what Aristotle calls
'prior in substance' than those at a higher level (2b7).
So, for instance, human is prior in substance than body. Whether this
is to be interpreted in terms of the greater *reality* of the
kind human is an open question. Nonetheless, Aristotle's
equating an increase in generality with a decrease in substantiality
is at least in spirit strongly anti-Platonic.



There is one other interesting general feature of this scheme that is
worth pointing out before looking at its details. Aristotle's
rejection of the view that being is a genus and his subsequent
acceptance of ten distinct highest kinds leads to a doctrine
concerning being itself that is at the center of Aristotle's
*Metaphysics*. (It should be noted, however, that there is
genuine disagreement over the extent to which Aristotle accepted the
doctrine of being that appears in the *Metaphysics* when he
wrote the *Categories*.) According to Aristotle, some words do
not express a genus but instead are what he calls *pros hen*
homonyms -- that is, homonyms *related to one thing (pros
hen)*, variously called cases of 'focal meaning' or
'focal connection' or 'core-dependent
homonymy' in the literature on this topic (1003a35 ff.). Such
words are applicable to various items in the world in virtue of the
fact that those items all bear some type of relation to some one thing
or type of thing. An example of such a homonym, according to
Aristotle, is 'healthy'. A regimen, he says, is healthy
because it is productive of health; urine is healthy because it is
indicative of health; and Socrates is healthy because he has health.
In this case, a regimen, urine, and Socrates are all called
'healthy' not because they stand under some one genus,
namely healthy things, but instead because they all bear some relation
to health. Similarly, according to Aristotle, things in the world are
not beings because they stand under some genus, being, but rather
because they all stand in a relation to the primary being, which in
the *Categories* he says is substance. This explains in part
why he says in the *Metaphysics* that in order to study being
one must study substance (1004a32, 1028a10-1028b8).


### 2.2 Detailed Discussion



It must be admitted, I think, that when stated in the abstract there
is a certain beauty about the structure of Aristotle's two
classificatory schemes. Aristotle's system, however, begins to
look somewhat awkward when his list of highest kinds is scrutinized.
Some of the categories are natural, but others seem much less so. As a
result, philosophers have proposed changes to Aristotle's list,
arguing that various categories should be eliminated, and scholars
have suggested that Aristotle's categories are not merely the
highest kinds but rather represent various complex relations between
words and different aspects of the world. A brief discussion of the
first four categories, which are the only ones that Aristotle
discusses at length, should bring out both the interest of
Aristotle's list as well as some of its peculiarities.


#### 2.2.1 Substance



The most fundamental category is substance. We have already seen that
according to Aristotle substances divide into primary and secondary
substances. Although Aristotle does not discuss the different kinds of
secondary substances in the *Categories*, various remarks he
makes throughout his corpus suggest that he would divide secondary
substances into at least the following kinds (*DA* 412a17,
413a21, 414a35, *Meta.* 1069a30, *NE* 1098a4):


* Substance
	+ Immobile Substances -- Unmoved Mover(s)
	+ Mobile Substances -- Body
		- Eternal Mobile Substances -- Heavens
		- Destructible Mobile Substances -- Sublunary bodies
			* Unensouled Destructible Mobile Substances -- Elements
			* Ensouled Destructible Mobile Substances -- Living things
				+ Incapable of Perception -- Plants
				+ Capable of Perception -- Animals
					- Irrational -- Non-Human Animals
					- Rational -- Humans



This genus/species hierarchy is far from complete --
Aristotle's biological treatises contain a remarkably rich
taxonomy of animals that is neither captured nor indeed obviously
commensurate with the division into irrational and rational
animals-- but it does nicely illustrate the general structure of
Aristotle's categories. The lowest species in this taxonomy give
way to kinds of increasing generality until the highest kind,
substance is reached. Moreover, there is something rather intuitive
about the idea that members of natural kinds are a fundamental type of
entity in the world and hence that there is a system of kinds of
increasing generality to which each such entity belongs. Of course,
someone might think that some kind stands above substance. But it is
not clear what such a kind would be except being, or perhaps the even
more general kind *thing;* and as I have already said, not only
does Aristotle reject the idea that being is a genus, but it is
difficult to see what the relevant sense of *thing* is, if this
is not simply another word for *substance*.


#### 2.2.2 Quantity



The second category Aristotle discusses in the *Categories* is
quantity, and in the chapter devoted to quantity Aristotle actually
divides quantity into distinct species. In fact, he gives two
divisions; but for the sake of illustrating the general nature of the
category, discussing the first division he gives should suffice.
According to Aristotle, quantity divides into continuous and discrete
quantities; continuous quantity divides into line, surface, body,
time, and place; and discrete quantity divides into number and speech
(4b20-23). Hence, we have the following genus/species
structure:


* Quantity
	+ Continuous Quantities
		- line
		- surface
		- body
		- time
		- place
	+ Discrete Quantities
		- number
		- speech



Like substance, quantity seems like a reasonable candidate for a
highest kind -- quantities exist; quantities are not substances;
substances are not quantities, and it is not clear what kind would
stand above quantity. So, Aristotle's decision to make quantity
a highest kind appears well motivated. Aristotle's treatment of
quantity, however, does raise some difficult questions.



Perhaps the most interesting question concerns the fact that some of
the species in quantity appear to be quantified things rather than
quantities themselves. Consider, for instance, body. In its most
natural sense, 'body' signifies bodies, which are not
quantities but rather things with quantities. The same is true of
line, surface, place, and arguably speech. Of course, there are
quantities naturally associated with some of these species. For
instance, length, breadth, and depth are associated with line, body,
and surface. But Aristotle does not list these as the species under
quantity. So, in the first instance, we can ask: does Aristotle intend
his division of Quantity to be a division of quantities or quantified
things?



The difficulties involved in Aristotle's list of species in the
category of quantity can be made more precise by noting that in
several places he seems to commit himself to the view that body is a
species in the category of substance (*Top.* 130b2, *DC*
2681-3, *DA* 434b12, *Meta.* 1079a31, 1069b38).
And as I have drawn the genus-species structure in the category of
substance above, body is one of the two species immediately under
substance. Yet body also appears as a species under the species
Continuous Quantity. The difficulty arises because Aristotle is
committed to the view that no species can occur in both the category
of substance and in some other category. For, he thinks that a species
in substance is said-of primary substances while species in the other
categories are not said-of primary substances. Hence, any species in
both substance and some accidental category would be said-of and not
said-of primary substance. Aristotle's list of species in the
Category of Quantity is thus not merely puzzling but seems to commit
Aristotle to a contradiction. So, a second question about
Aristotle's category of quantity naturally suggests itself: how
can body be a species in both the category of quantity and the
category of substance? (Studtman 2002)



A number of other questions about Quantity could be asked. For
instance, Aristotle's treatment of quantity in the
*Metaphysics* includes species not present in his treatment in
the *Categories* (*Meta.* 1020a7-34), which raises
questions as to the extent to which the set of doctrines in the
*Categories* coheres with the doctrines in his other physical
and metaphysical works. Furthermore, questions about Aristotle's
views about the nature of some of the species in quantity arise. So,
for instance, to what does Aristotle think the species number
corresponds? He surely does not think that numbers exist apart from
the material world. But then what exactly does Aristotle think a
number is? All we get for an answer from the *Categories* is
that number is a discrete quantity. But such an answer hardly provides
much of an understanding as to what Aristotle has precisely in mind.
Moreover, why does Aristotle include speech as a species in the
category of quantity? Speech hardly seems like a natural candidate for
this category. Perhaps, Aristotle has in mind the quantities of vowels
and syllables of Greek words. But, if anything, speech would seem to
be some kind of vocal sound, which arguably is a kind of affection.
Each of these questions is interesting and worth pursuing. I shall
not, however, offer any answers to them here. Rather, I hope only to
have illustrated how deeply intriguing and yet difficult to pin down
fully Aristotle's *Categories* is.


#### 2.2.3 Relatives



After quantity, Aristotle discusses the category of relatives, which
both interpretively and philosophically raises even more difficulties
than his discussion of quantity. A contemporary philosopher might
naturally think that this category contains what we would nowadays
call 'relations'. But this would be a mistake. The name
for the category is *ta pros ti* (ta
pros ti), which literally means
'things toward something'. In other words, Aristotle seems
to be classifying not relations but rather things in the world in so
far as they are toward something else. It would seem, however, that
for Aristotle things are toward something else insofar as a relational
predicate applies to them. Aristotle says: Things are called
'relative' if *as such* they are said to be of
something else or to be somehow referred to something else. So, for
instance, the greater, *as such*, is said to be of something
else, for it is said to be greater than something (6a36).



Perhaps the most straightforward reading of Aristotle's
discussion is the following. He noticed that certain predicates in
language are logically incomplete -- they are not used in simple
subject/predicate sentences of the form '*a* is
*F*' but rather require some type of completion. To say
'three is greater' is to say something that is incomplete
-- to complete it requires saying what three is greater than.
Nonetheless, Aristotle accepted a doctrine according to which
properties in the world always inhere in a single subject. In other
words, although Aristotle countenanced relational predicates, and
though he certainly thought that objects in the world are related to
other objects, he did not accept relations as a genuine type of
entity. So, Aristotle's category of relatives is a kind of
halfway house between the linguistic side of relations, namely
relational predicates, and the ontological side, namely relations
themselves.



For our purposes, we need not determine how to best interpret
Aristotle's theory of relatives, but can rather consider some
issues that Aristotle's discussion raises. First, anyone who is
comfortable with relational properties will no doubt find
Aristotle's discussion somewhat confused. Although Aristotle
does discuss important features of relational predicates, for
instance, that relational predicates involve a kind of reciprocal
reference (6b28), his fundamental stance, according to which all
properties in the world are non-relational, will appear wrongheaded.
Second, Aristotle's category of relatives raises interpretive
issues, in particular the issue concerning what exactly his
categorical scheme is meant to classify. As in the case of quantity,
Aristotle seems to be focusing on things that are related rather than
relations themselves. Indeed, this is evident from the name of the
category.



This latter fact, namely that in his discussion of relatives Aristotle
seems focused on related things rather than relations, places pressure
on the easy characterization of the categories that I discussed
previously, namely that each category is a distinct type of
extra-linguistic entity. If that easy characterization were correct,
Aristotle should have countenanced some type of entity corresponding
to relatives as a highest kind. But he did not. Hence, it is tempting
to shift to an interpretation according to which Aristotle is after
all focused on linguistically characterized items. And perhaps he
thinks that the world contains just a few basic types of entity and
that different types of predicates apply to the world in virtue of
complex semantic relations to just those types of entity. As it turns
out, many commentators have interpreted him in this way. But their
interpretations face their own difficulties. To raise just one, we can
ask: what are the basic entities in the world if not just those that
fall under the various categories? Perhaps there is a way to answer
this question on Aristotle's behalf, but the answer is not
clearly contained in his texts. So again we are once again forced to
admit just how difficult it is to pin down a precise interpretation of
Aristotle's work.


#### 2.2.4 Quality



After relatives, Aristotle discusses the category of quality. Unlike
quantity and relatives, quality does not present any obvious
difficulties for the interpretation according to which the
*Categories* classify basic types of entity. Aristotle divides
quality as follows (8b26-10a11):


* Quality
	+ Habits and Dispositions
	+ Natural Capabilities and Incapabilities
	+ Affective Qualities and Affections
	+ Shape



Each of these species looks like an extra-linguistic type of entity,
and none of the species appears to be a species in another category.
Hence, any difficulties with Aristotle's treatment of quality
concern the appropriateness of the divisions he makes rather than the
extent to which the category fits into a larger interpretation of the
categorial scheme. But, as with just about everything in
Aristotle's scheme, the divisions he makes among qualities have
been severely criticized. J.L. Ackrill, for instance, criticizes
Aristotle as follows:



> 
> He [Aristotle] gives no special argument to show that [habits and
> dispositions] are qualities. Nor does he give any criterion for
> deciding that a given quality is or is not a [habit-or-disposition];
> why, for example, should affective qualities be treated as a class
> quite distinct from [habits and dispositions]? (Ackrill 1963)
> 



Ackrill finds Aristotle's division of quality at best
unmotivated. And Ackrill, it would seem, is being polite. Montgomery
Furth has said: 'I shall largely dispense with questions
like...the rationale (if there be one) for comprehending into a
single category the monstrous motley horde yclept
Quality...' (Furth 1988).



It must be admitted, that Aristotle's list of the species in
quality is at first blush a bit odd. For instance, why should we
consider any of the species listed as falling directly under quality?
Indeed, when Aristotle lists the species, he does not follow his usual
procedure and provide the differentiae that distinguish them. If there
are such differentiae, we should expect that habits and dispositions,
for instance, can be defined as such and such a quality. The same
would of course be true for the other qualities. But not only does
Aristotle not provide these differentiae, but it is also difficult to
see what they might be. To appreciate the difficulty, one need only
ask: what differentia can be added to quality so as to define
shape?



To be fair, Aristotle's category of quality has had its
defenders. In fact, some of those defenders have gone so far as to
provide something of a deduction of the species in the category from
various metaphysical principles. Aquinas, for instance, says the
following about the category in his *Summa Theologiae*:



> 
> 
> Now the mode of determination of the subject to accidental being may
> be taken in regard to the very nature of the subject, or in regard to
> action, and passion resulting from its natural principles, which are
> matter and form; or again in regard to quantity. If we take the mode
> or determination of the subject in regard to quantity, we shall then
> have the fourth species of quality. And because quantity, considered
> in itself, is devoid of movement, and does not imply the notion of
> good or evil, so it does not concern the fourth species of quality
> whether a thing be well or ill disposed, nor quickly or slowly
> transitory.
> 
> 
> 
> But the mode of determination of the subject, in regard to action or
> passion, is considered in the second and third species of quality. And
> therefore in both, we take into account whether a thing be done with
> ease or difficulty; whether it be transitory or lasting. But in them,
> we do not consider anything pertaining to the notion of good or evil:
> because movements and passions have not the aspect of an end, whereas
> good and evil are said in respect of an end.
> 
> 
> 
> On the other hand, the mode or determination of the subject, in regard
> to the nature of the thing, belongs to the first species of quality,
> which is habit and disposition: for the Philosopher says
> (*Phys*. vii, text. 17), when speaking of habits of the soul
> and of the body, that they are "dispositions of the perfect to
> the best; and by perfect I mean that which is disposed in accordance
> with its nature." And since the form itself and the nature of a
> thing is the end and the cause why a thing is made (*Phys*. ii,
> text. 25), therefore in the first species we consider both evil and
> good, and also changeableness, whether easy or difficult; inasmuch as
> a certain nature is the end of generation and movement. (Aquinas,
> *Summa Theologica*, Part I-II, Q. 49, Art. 2)
> 
> 
> 



Aquinas seems to see the species in the category of quality as
unfolding systematically from some basic metaphysical principles.
Whether Aquinas's derivation of the species in the category of
quality is plausible or whether some other derivation that stems from
Aristotelian principles can be given has become the subject of recent
scholarship (Kahm 2016, Studtmann 2003a). Although the issue may seem
a local one pertaining only to Aristotle's category of quality,
it is in fact relevant to the larger issue, which I will discuss
shortly, of Aristotle's method of deriving the categories
generally. A systematic derivation of Aristotle's category of
quality would give credence to the claim that Aristotle's
categorial scheme as a whole admits of some kind of systematic
derivation.



It may seem odd to quote Aquinas at such length in an essay devoted to
Aristotle's categories, but I have done so for two reasons.
First, as Ackrill's and Furth's comments illustrate,
Aristotle's scheme has been severely criticized by scholars and
philosophers alike. Aquinas's comments about quality, however,
show that in the hands of a truly talented interpreter -- and
there certainly has been no interpreter of Aristotle greater than
Aquinas -- many of the criticisms can be met. Second, and more
importantly, the attention that Aquinas gives to the category of
quality is indicative of one of the most important facts about
Aristotle's categories, namely its profound historical
importance in the development of metaphysical speculation. Whether
philosophers have agreed or disagreed with Aristotle's
categorial scheme, his categorialism has played a significant
instrumental role -- it has provided in the millennia since its
appearance the starting point for a great deal of metaphysical
inquiry. In this respect, it can be compared to the quantifier in
Twentieth-century metaphysics. Whether or not the quantifier is of
philosophical interest, it is hard to imagine twentieth-century
analytical metaphysics without it. So, to the extent that interest in
the history of philosophy lies in the way in which ideas have had an
influence from generation to generation, Aristotle's categorial
scheme is worth studying not only for the doctrines it contains but
also for the interest that other philosophers have taken in it and the
philosophy that they produced by using it as a springboard. (See the
entry on
 Commentators on Aristotle.)



It is a tradition that scholars are increasingly attending to. Much of
the recent scholarship concerning Aristotle's
*Categories* has either been translations of commentaries or
discussions that stem from them.



After quality, Aristotle's discussion of individual categories
becomes very sparse. He devotes a few comments to the categories of
action and passion (11b1) and then has a brief discussion of one of
the odder categories, having, at the end of the work
(15b17-35).



The bulk of the remaining discussion, which is known as the
*Post-Predicamenta*, is directed at concepts involving some
kind of opposition, the concepts of priority, posteriorty,
simultaneity, and change. Although the latter part of the
*Categories* is interesting, it is not clear that it is
integral to either of Aristotle's classificatory schemes.
Moreover, his discussion there is largely superseded by his discussion
of the same concepts in the *Metaphysics*. Hence, instead of
discussing the *Post-Predicamenta* in detail, I shall at this
point turn to a topic about Aristotle's categories that is of
fundamental philosophical and interpretive interest: how did Aristotle
arrive at his list of categories?


## 3. Whence the Categories?



The issue concerning the origin of the categories can be raised by
asking the most difficult question there is about any philosophical
position: why think that it is correct? Why, in other words, should we
think that Aristotle's list of highest kinds contains all and
only the highest kinds there are?



One might, of course, reject the idea that there are some
metaphysically privileged kinds in the world. But here it is important
to distinguish between internal and external questions concerning a
system of categories. We can approach category theory externally in
which case we would ask questions about the status of any system of
categories. So, for instance, we could ask whether any system of
categories must exhibit some kind of dependency on the mind, language,
conceptual schemes, or whatever. Realists will answer this question in
the negative, and idealists of one stripe or another in the
affirmative. In addition, we can ask about our epistemic access to the
ultimate categories in the world. And we can adopt positions ranging
from a radical skepticism about our access to categories to a kind of
infallibilism about such access.



If, on the other hand, we approach category theory from an internal
perspective, we will assume some answer to the external questions and
then go on to ask about the correctness of the system of categories
under those assumptions. So, for instance, we might adopt a realist
perspective and hence assume that there is some correct metaphysically
privileged list of mind and language independent highest kinds as well
as a correct account of the relations between them. And we can then
try to determine what that list is. Now, Aristotle certainly belongs
to this latter tradition of speculation about categories: he assumes
rather than defends a posture of realism with respect to the
metaphysical structures in the world. It is thus appropriate to assume
realism along with him and then inquire into the question of which
categories there might be.



One way of approaching this question is to ask whether there is some
principled procedure by which Aristotle generated his list of
categories. For, if there is, then one could presumably assess his
list of highest kinds by assessing the procedure by which he generated
it. Unfortunately, with the exception of some suggestive remarks in
the *Topics*, Aristotle does not indicate how he generated his
scheme. Without some procedure by which one can generate his list,
however, Aristotle's categories arguably lack any justification.
The issue is, of course, complicated by the fact that his list might
be justified without some procedure to generate it -- perhaps we
can use a combination of metaphysical intuition and philosophical
argumentation to convince ourselves that Aristotle's list is
complete. Nonetheless, without some procedure of generation
Aristotle's categories at least appear in an uneasy light. And
as a matter of historical fact, the lack of any justification for his
list of highest kinds has been the source of some famous criticisms.
Kant, for instance, just prior to the articulation of his own
categorial scheme, says:



> 
> It was an enterprise worthy of an acute thinker like Aristotle to make
> search for these fundamental concepts. But as he did so on no
> principle, he merely picked them up as they came his way, and at first
> procured ten of them, which he called *categories*
> (predicaments). (Kant, *Critique of Pure Reason*,
> Transcendental Doctrine of Elements, Second Part, First Division, Book
> I, Chapter 1, Section 3, 10)
> 



According to Kant, Aristotle's list of categories was the result
of an unsystematic, albeit a brilliant, bit of philosophical
brainstorming. Hence, it cannot stand firm as a correct set of
categories.



As it turns out, although Kant did not know of any procedure by which
Aristotle might have generated his list of categories, scholars have
given a number of proposals. The proposals can be classified into four
types, which I shall call: (1) *The Question Approach*; (2)
*The Grammatical Approach*; (3) *The Modal Approach*;
(4) *The Medieval Derivational Approach.*



J.L. Ackrill (1963) is the most prominent defender of the Question
Approach. He takes as evidence for his interpretation
Aristotle's remarks in *Topics* I 9. Ackrill claims that
there are two different ways to generate the categories, each of which
involves asking questions. According to the first method, we are to
ask a single question -- what is it? -- of as many things as
we can. So, for instance, we can ask of Socrates, what is Socrates?
And we can answer -- Socrates is a human. We can then direct the
same question to the answer we have given: what is a human? And we can
answer: a human is an animal. Eventually, this process of question
asking will lead us to some highest kind, in this case, Substance. If,
on the other hand, we had begun asking that same question of
Socrates' color, say his whiteness, we would eventually have
ended at the highest kind quality. When carried out completely,
Ackrill claims, this procedure will yield the ten distinct and
irreducible kinds that are Aristotle's categories. According to
the second method of questioning, we are to ask as many different
questions as we can about a single primary substance. So, for
instance, we might ask -- how tall is Socrates? Where is
Socrates? What is Socrates? And in answering these questions, we will
respond five feet, in the Agora, Human. We will then realize that our
answers to our various questions group into ten irreducible kinds.



Of all the proposals that scholars have given, Ackrill's is the
most supported by Aristotle's texts, though the evidence he
cites is far from conclusive. But from a philosophical point of view,
the question method suffers from some serious problems. First, it is
far from clear that either method actually produces Aristotle's
list. Suppose, for instance, I employ the second method and ask: does
Socrates like Plato? The answer, let us grant, is 'yes'.
But where does that answer belong in the categorical scheme? Ackrill
might respond by forcing the question to be one that is not answered
with 'yes' or 'no'. But we can still ask the
question: is Socrates present-in or not present-in something else? The
answer, of course, is: not present-in; but where in Aristotle's
list of categories does not present-in belong? It is indeed hard to
see. Similar problems face the first method. Suppose I were to ask:
what is Socrates' whiteness? I might respond by saying 'a
particular'. Again, where does being a particular belong in
Aristotle's list of categories. Of course, particulars are part
of the four-fold system of classification that Aristotle articulates.
But we are not at the moment concerned with that scheme. Indeed, to
advert to that scheme in the present context is simply to re-open the
question of the relations between the two main systems of
classification in the *Categories.*



Even if Ackrill can find some plausible route from questions to
Aristotle's categories, the methods he proposes still seem
unsatisfactory for the simple reason that they depend far too much on
our question-asking inclinations. It may be that the questions that we
in fact ask will yield Aristotle's categories, but what we
should want to know is whether we are asking the right questions.
Unless we can be confident that our questions are tracking the
metaphysical structures of the world, we should be unimpressed by the
fact that they yield any set of categories. But to know whether our
questions are tracking the metaphysical structures of the world
requires us to have some way of establishing the correctness of the
categorial scheme. Clearly, at this point, we are in a circle that is
too small to be of much help. Maybe all metaphysical theorizing is at
some level laden with circularity, but circles this small are
generally unacceptable to a metaphysician.



According to the grammatical approach, which traces to Trendelenburg
(1846) and has most recently been defended by Michael Baumer (1993),
Aristotle generated his list by paying attention to the structures
inherent in language. On the assumption that the metaphysical
structure of the world mirrors the structures in language, we should
be able to find the basic metaphysical structures by examining our
language. This approach is quite involved but for our purposes can be
illustrated with a few examples. The distinction between substance and
the rest of the categories, for instance, is built into the
subject-predicate structure of our language. Consider, for instance,
the two sentences: (1) Socrates is a human; and (2) Socrates is white.
First, we see that each sentence has a subject, namely
'Socrates'. Corresponding to that subject, one might
think, is an entity of some kind, namely a primary substance.
Moreover, the first sentence contains what might be called an
individuating predicate -- it is a predicate of the form,
*a* such and such, rather than of the form, such and such. So,
one might think, there are predicates that attribute to primary
substances properties the having of which suffices for that substance
to be an individual of some kind. On the other hand, the second
sentence contains a non-individuating predicate. So by examining the
details of the predicates in our language, we have some grounds for
distinguishing between the category of substance and the accidental
categories.



The grammatical approach certainly does have some virtues. First, we
have ample evidence that Aristotle was sensitive to language and the
structures inherent in it. So it would not be all that surprising were
he led by his sensitivity to linguistic structures to his list of
categories. Moreover, some of the peculiarities of his list are nicely
explained in this way. Two of the highest kinds are action and
passion. In *Physics* III 3, however, Aristotle argues that in
the world there is only motion and that the distinction between action
and passion lies in the way in which one is considering the motion. So
why should there be two distinct categories, namely action, and
passion, rather than just one, namely motion? Well, the grammatical
approach offers an explanation: in language, we differentiate between
active and passive verbs. Hence, there are two distinct categories,
not just one.



Despite these virtues, the grammatical approach faces a difficult
question: why think that the structures we find in language reflect
the metaphysical structures of the world? For instance, it may simply
be a historical accident that our language contains individuating and
non-individuating predicates. Likewise, it may be a historical
accident that there are active and passive verbs in our language. Of
course, this type of objection, when pushed to its limits, leads to
one of the more difficult philosophical questions, namely how can we
be sure that the structures of our representations are in any way
related to what some might call the basic metaphysical structures and
to what others might call the things in themselves? But one might hold
out hope that some justification for a categorial scheme could be
given that did not rest entirely on the unjustified assertion of some
deep correspondence between linguistic and metaphysical
structures.



The Modal Approach, which traces to Bonitz (1853) and has most
recently been defended by Julius Moravscik (1967), avoids the defects
of both the previous two approaches. As Moravscik formulates this
view, the categories are those types of entities to which any sensible
particular *must* be related. He says:



> 
> According to this interpretation the constitutive principle of the
> list of categories is that they constitute those classes of items to
> each of which any sensible particular -- substantial or otherwise
> -- must be related. Any sensible particular, substance, event,
> sound, etc. must be related to some substance; it must have some
> quality and quantity; it must have relational properties, it must be
> related to times and places; and it is placed within a network of
> causal chains and laws, thus being related to the categories of
> affecting and being affected.
> 



In virtue of its explicitly modal nature, the Modal Approach avoids
the defects of the previous two approaches. Whereas the first two
approaches ultimately rely on some connection between metaphysical
structures and what appear to be merely contingent features of either
our question asking proclivities or the structures inherent in our
language, the Modal Approach eliminates contingency altogether.



Despite its explicitly modal character, the Modal Approach does face a
difficulty similar to the one faced by the Question Approach. It might
turn out that employing the approach yields exactly the list of
Aristotle's categories, but then again it might not. So, for
instance, every material particular must be related to a particular.
But there is no category of particulars. There are, of course, beings
that are not said-of other beings. But not being said-of is not one of
Aristotle's categories. Moreover, must not every material
particular be related to matter? But matter is not a highest kind.
Indeed, it is far from clear where matter belongs in the categories.
So, even if the Modal Approach is a good one for generating some list
of kinds, it is not obvious that it is a good approach for generating
Aristotle's list of kinds. This problem could of course be
alleviated somewhat if instead of merely appealing to modal structures
as such, one could appeal to modal structures that arguably Aristotle
would have thought are part of the very fabric of the world. Then one
would at least have an explanation as to why Aristotle derived the
list he in fact derived, even if one is inclined to reject
Aristotle's list.



The last approach to the categories, namely the Medieval derivational
approach, goes some way in the direction suggested but not taken by
Moravscik's Modal Approach. There is a rich tradition of
commentators including Radulphus Brito, Albert the Great, Thomas
Aquinas, and most recently their modern heir Franz Brentano, who
provide precisely the kind of derivation for Aristotle's
categorial scheme found wanting by Kant. According to the commentators
in this tradition, Aristotle's highest kinds are capable of a
systematic and arguably entirely *a priori* derivation. The
following quotation from Brentano captures nicely the philosophical
import of such derivations.



> 
> On the contrary, it seems to me that there is no doubt that Aristotle
> could have arrived at a certain *a priori* proof, a deductive
> argument for the completeness of the distinction of categories
> ... (*On the Several Senses of Being in Aristotle*, Ch.5,
> section 12)
> 



Brentano's enthusiasm about the possibility of deriving
Aristotle's categories is perhaps unjustified, but the idea that
an *a priori* proof of the completeness of Aristotle's
categories is certainly an intriguing one.



Perhaps the best representative of this type of interpretation occurs
in Aquinas's commentaries on Aristotle's
*Metaphysics*. All of Aquinas's derivation deserves
considerable attention, but for our purposes, it will suffice to quote
just a portion of it so as to bring out its general character as well
as one of its more interesting aspects.



> 
> A predicate is referred to a subject in a second way when the
> predicate is taken as being in the subject, and this predicate is in
> the subject either essentially and absolutely and as something flowing
> from its matter, and then it is quantity; or as something flowing from
> its form, and then it is quality; or it is not present in the subject
> absolutely but with reference to something else, and then it is
> relation. (*Commentaries on Aristotle's Metaphysics*,
> Book V, Lesson 9, Section 890)
> 



This passage illustrates the tenor of the Medieval derivational
approach. Aquinas articulates what appear to be principled
metaphysical principles concerning the way in which a predicate can
be, in his words, 'taken as being in a subject'. There are
two such ways: (1) essentially and absolutely; or (2) essentially and
not absolutely but with reference to something else. The latter way
corresponds to the category of relatives; the former, to the
categories of quality and quantity. Aquinas then divides the former
way of being in a subject in terms of form and matter. He claims,
strikingly, that the category of quality *flows from* form and
that the category of quantity *flows from* matter.



Inspecting all of Aquinas's derivation to determine its cogency
is far too large a project to undertake here. I have quoted the
portion above to show the way in which the Medieval derivational
approach augments in an interesting way Moravscik's Modal
Approach. The Modal Approach, I argued, would gain some plausibility
if there were some way of seeing Aristotle's own attitudes about
the modal structures in the material world somehow determining the
generation of the categories. By invoking a combination of *a
priori* sounding semantic principles and theses about the
relationship between form and quality and matter and quantity, Aquinas
has gone some way toward doing this. Aristotle is certainly committed
to the claim that form and matter are two of the absolutely
fundamental aspects of the material world. Indeed, he argues in the
*Physics* that form and matter are necessary for the existence
of motion, which, he thinks, essentially characterizes bodies.



If the Medieval Derivational Approach is correct, Aristotle's
categories ultimately trace to the ways in which form, matter, and
perhaps motion relate to substances and the predicates that apply to
them. Whether the derivations can withstand philosophical scrutiny is
of course an important question, one that I will not pursue here,
though I will say that Brentano was probably a bit too enthusiastic
about the prospects for an entirely satisfactory *a priori*
proof of the completeness of Aristotle's categories. Moreover,
the Medieval interpretations face the charge that they are an
over-interpretation of Aristotle. Aristotle simply does not provide in
his surviving writings the sort of conceptual connections that
underlie the Medieval derivations. So perhaps the Medievals have
succumbed to the temptation to read into Aristotle's system
connections that Aristotle did not accept. Indeed, from a
twentieth-century perspective, the Medieval derivations look very
strange. It is commonplace in contemporary Aristotle scholarship to
view the *Categories* as an early work and to think that
Aristotle had not developed his theory of form and matter until later
in his career. If this general approach is correct, the claim that the
categorial scheme can somehow be derived at least in part from form
and matter appears implausible.



As should be clear from this brief discussion, providing a complete
derivation of Aristotle's categorical scheme would be a
difficult, indeed perhaps impossible, task. After all, someone might
conclude that Aristotle's categorial scheme was either in part
or in whole mistaken. Minimally, the task is a daunting one. But of
course, the difficulty in establishing its ultimate correctness is not
peculiar to Aristotle's categorial scheme. Indeed, it should not
be at all surprising that the difficulties that have beset
metaphysical speculation in the Western tradition can be seen in such
a stark and provocative fashion in one of the great founding works of
that very tradition. In fact, it is in part due to such difficulties
that external questions about categorial and other metaphysical
structures arise. Such difficulties understandably lead to questions
about the legitimacy of category theory and metaphysical speculation
in general. Unfortunately, the history of metaphysical speculation has
shown that it is no less difficult to establish answers to external
than to internal questions about category theory. That acknowledged it
is noteworthy that questions of both sorts owe their first
formulations, ultimately, to the categorialism of Aristotle's
seminal work, the *Categories*.


## 4. Recent Work



Two trends in recent philosophical scholarship are of special note.
These engage Aristotle's categorialism in different ways. The
first considers it directly, as a topic of investigation in its own
right; see Shields (ed.) 2012. The second treats it more indirectly,
either by considering issues in Aristotle's philosophy on which
his categorialism bears or, more generally, by advancing the tradition
his categorialism inaugurated; see Haaparanta and Koskinen (eds.)
2012.



In Shields (ed.) 2012, we find an argument that Aristotle's
categorialism and his hylomorphism can be systematically unified
(Studtmann 2012). The role of the famous phrase--Being Qua
Being--in Aristotle's thought is thoroughly examined, first
by way of the many criticisms of Aristotle's views and second by
way of interpretation of Aristotle's famous slogan that can
withstand philosophical scrutiny (Shields 2012). The ontology of the
Categories is examined with a critical lens sharpened by a number of
contemporary debates (Loux 2012a).



Haaparanta and Koskinen (eds.) 2012 begins with Michael Loux's
(2012b) examination of a thesis that structures Aristotle's
categorialism, namely that being is said in many ways (pollachos
legomenon). Many commentators have thought such a thesis to be deeply
problematic. Loux agrees in part with such a sentiment, arguing that
the thesis makes univocal but transcategorial reference impossible,
thereby rendering a statement of the thesis that being is said in many
ways impossible as well. Loux, however, finds a way to salvage the
Aristotelian thesis by denying the claim that it is about the meaning
or sense of universal terms. The volume continues with discussions
that become increasingly remote in time but which therefore show the
lasting influence of his categorialism. Kukkonen (2012), Knuttilla
(2012), and Normore (2012) discuss in separate essays the influence
Aristotle's categories on aspects of Medieval philosophy. And by
the latter part of the volume, the essays begin to focus on other
philosophers, e.g., Hegel, Pierce, Bolzano, and Meinong, each of whom
avowedly manifests a clear and deep debt to Aristotle and his
categorialism.