smooth, because its parts lie, so to speak, evenly; rough, because
some parts project beyond others.

  There may be other sorts of quality, but those that are most
properly so called have, we may safely say, been enumerated.

  These, then, are qualities, and the things that take their name from
them as derivatives, or are in some other way dependent on them, are
said to be qualified in some specific way. In most, indeed in almost
all cases, the name of that which is qualified is derived from that of
the quality. Thus the terms 'whiteness', 'grammar', 'justice', give us
the adjectives 'white', 'grammatical', 'just', and so on.

  There are some cases, however, in which, as the quality under
consideration has no name, it is impossible that those possessed of it
should have a name that is derivative. For instance, the name given to
the runner or boxer, who is so called in virtue of an inborn capacity,
is not derived from that of any quality; for lob those capacities have
no name assigned to them. In this, the inborn capacity is distinct
from the science, with reference to which men are called, e.g.
boxers or wrestlers. Such a science is classed as a disposition; it
has a name, and is called 'boxing' or 'wrestling' as the case may
be, and the name given to those disposed in this way is derived from
that of the science. Sometimes, even though a name exists for the
quality, that which takes its character from the quality has a name
that is not a derivative. For instance, the upright man takes his
character from the possession of the quality of integrity, but the
name given him is not derived from the word 'integrity'. Yet this does
not occur often.

  We may therefore state that those things are said to be possessed of
some specific quality which have a name derived from that of the
aforesaid quality, or which are in some other way dependent on it.

  One quality may be the contrary of another; thus justice is the
contrary of injustice, whiteness of blackness, and so on. The
things, also, which are said to be such and such in virtue of these
qualities, may be contrary the one to the other; for that which is
unjust is contrary to that which is just, that which is white to
that which is black. This, however, is not always the case. Red,
yellow, and such colours, though qualities, have no contraries.

  If one of two contraries is a quality, the other will also be a
quality. This will be evident from particular instances, if we apply
the names
used to denote the other categories; for instance, granted that
justice is the contrary of injustice and justice is a quality,
injustice will also be a quality: neither quantity, nor relation,
nor place, nor indeed any other category but that of quality, will
be applicable properly to injustice. So it is with all other
contraries falling under the category of quality.

  Qualities admit of variation of degree. Whiteness is predicated of
one thing in a greater or less degree than of another. This is also
the case with reference to justice. Moreover, one and the same thing
may exhibit a quality in a greater degree than it did before: if a
thing is white, it may become whiter.

  Though this is generally the case, there are exceptions. For if we
should say that justice admitted of variation of degree,
difficulties might ensue, and this is true with regard to all those
qualities which are dispositions. There are some, indeed, who
dispute the possibility of variation here. They maintain that
justice and health cannot very well admit of variation of degree
themselves, but that people vary in the degree in which they possess
these qualities, and that this is the case with grammatical learning
and all those qualities which are classed as dispositions. However
that may be, it is an incontrovertible fact that the things which in
virtue of these qualities are said to be what they are vary in the
degree in which they possess them; for one man is said to be better
versed in grammar, or more healthy or just, than another, and so on.

  The qualities expressed by the terms 'triangular' and 'quadrangular'
do not appear to admit of variation of degree, nor indeed do any
that have to do with figure. For those things to which the
definition of the triangle or circle is applicable are all equally
triangular or circular. Those, on the other hand, to which the same
definition is not applicable, cannot be said to differ from one
another in degree; the square is no more a circle than the
rectangle, for to neither is the definition of the circle appropriate.
In short, if the definition of the term proposed is not applicable
to both objects, they cannot be compared. Thus it is not all qualities
which admit of variation of degree.

  Whereas none of the characteristics I have mentioned are peculiar to
quality, the fact that likeness and unlikeness can be predicated
with reference to quality only, gives to that category its distinctive
feature. One thing is like another only with reference to that in
virtue of which it is such and such; thus this forms the peculiar mark
of quality.

  We must not be disturbed because it may be argued that, though
proposing to discuss the category of quality, we have included in it
many relative terms. We did say that habits and dispositions were
relative. In practically all such cases the genus is relative, the
individual not. Thus knowledge, as a genus, is explained by
reference to something else, for we mean a knowledge of something. But
particular branches of knowledge are not thus explained. The knowledge
of grammar is not relative to anything external, nor is the
knowledge of music, but these, if relative at all, are relative only