Another sort of quality is that in virtue of which, for example,
we call men good boxers or runners, or healthy or sickly: in fact it
includes all those terms which refer to inborn capacity or incapacity.
Such things are not predicated of a person in virtue of his
disposition, but in virtue of his inborn capacity or incapacity to
do something with ease or to avoid defeat of any kind. Persons are
called good boxers or good runners, not in virtue of such and such a
disposition, but in virtue of an inborn capacity to accomplish
something with ease. Men are called healthy in virtue of the inborn
capacity of easy resistance to those unhealthy influences that may
ordinarily arise; unhealthy, in virtue of the lack of this capacity.
Similarly with regard to softness and hardness. Hardness is predicated
of a thing because it has that capacity of resistance which enables it
to withstand disintegration; softness, again, is predicated of a thing
by reason of the lack of that capacity.

  A third class within this category is that of affective qualities
and affections. Sweetness, bitterness, sourness, are examples of
this sort of quality, together with all that is akin to these; heat,
moreover, and cold, whiteness, and blackness are affective
qualities. It is evident that these are qualities, for those things
that possess them are themselves said to be such and such by reason of
their presence. Honey is called sweet because it contains sweetness;
the body is called white because it contains whiteness; and so in
all other cases.

  The term 'affective quality' is not used as indicating that those
things which admit these qualities are affected in any way. Honey is
not called sweet because it is affected in a specific way, nor is this
what is meant in any other instance. Similarly heat and cold are
called affective qualities, not because those things which admit
them are affected. What is meant is that these said qualities are
capable of producing an 'affection' in the way of perception. For
sweetness has the power of affecting the sense of taste; heat, that of
touch; and so it is with the rest of these qualities.

  Whiteness and blackness, however, and the other colours, are not
said to be affective qualities in this sense, but -because they
themselves are the results of an affection. It is plain that many
changes of colour take place because of affections. When a man is
ashamed, he blushes; when he is afraid, he becomes pale, and so on. So
true is this, that when a man is by nature liable to such
affections, arising from some concomitance of elements in his
constitution, it is a probable inference that he has the corresponding
complexion of skin. For the same disposition of bodily elements, which
in the former instance was momentarily present in the case of an
access of shame, might be a result of a man's natural temperament,
so as to produce the corresponding colouring also as a natural
characteristic. All conditions, therefore, of this kind, if caused
by certain permanent and lasting affections, are called affective
qualities. For pallor and duskiness of complexion are called
qualities, inasmuch as we are said to be such and such in virtue of
them, not only if they originate in natural constitution, but also
if they come about through long disease or sunburn, and are
difficult to remove, or indeed remain throughout life. For in the same
way we are said to be such and such because of these.

  Those conditions, however, which arise from causes which may
easily be rendered ineffective or speedily removed, are called, not
qualities, but affections: for we are not said to be such virtue of
them. The man who blushes through shame is not said to be a
constitutional blusher, nor is the man who becomes pale through fear
said to be constitutionally pale. He is said rather to have been
affected.

  Thus such conditions are called affections, not qualities.

  In like manner there are affective qualities and affections of the
soul. That temper with which a man is born and which has its origin in
certain deep-seated affections is called a quality. I mean such
conditions as insanity, irascibility, and so on: for people are said
to be mad or irascible in virtue of these. Similarly those abnormal
psychic states which are not inborn, but arise from the concomitance
of certain other elements, and are difficult to remove, or
altogether permanent, are called qualities, for in virtue of them
men are said to be such and such.

  Those, however, which arise from causes easily rendered
ineffective are called affections, not qualities. Suppose that a man
is irritable when vexed: he is not even spoken of as a bad-tempered
man, when in such circumstances he loses his temper somewhat, but
rather is said to be affected. Such conditions are therefore termed,
not qualities, but affections.

  The fourth sort of quality is figure and the shape that belongs to a
thing; and besides this, straightness and curvedness and any other
qualities of this type; each of these defines a thing as being such
and such. Because it is triangular or quadrangular a thing is said
to have a specific character, or again because it is straight or
curved; in fact a thing's shape in every case gives rise to a
qualification of it.

  Rarity and density, roughness and smoothness, seem to be terms
indicating quality: yet these, it would appear, really belong to a
class different from that of quality. For it is rather a certain
relative position of the parts composing the thing thus qualified
which, it appears, is indicated by each of these terms. A thing is
dense, owing to the fact that its parts are closely combined with
one another; rare, because there are interstices between the parts;