The Categories - Aristotle (reading eggs books .TXT) 📗
- Author: Aristotle
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For instance, if the characteristic ‘terrestrial’ is predicated
of the species ‘man’, the definition also of that characteristic
may be used to form the predicate of the species ‘man’: for ‘man’
is terrestrial.
The fact that the parts of substances appear to be present in the
whole, as in a subject, should not make us apprehensive lest we
should have to admit that such parts are not substances: for in
explaining the phrase ‘being present in a subject’, we stated’
that we meant ‘otherwise than as parts in a whole’.
It is the mark of substances and of differentiae that, in all
propositions of which they form the predicate, they are
predicated univocally. For all such propositions have for their
subject either the individual or the species. It is true that,
inasmuch as primary substance is not predicable of anything, it
can never form the predicate of any proposition. But of secondary
substances, the species is predicated of the individual, the
genus both of the species and of the individual. Similarly the
differentiae are predicated of the species and of the
individuals. Moreover, the definition of the species and that of
the genus are applicable to the primary substance, and that of
the genus to the species. For all that is predicated of the
predicate will be predicated also of the subject. Similarly, the
definition of the differentiae will be applicable to the species
and to the individuals. But it was stated above that the word
‘univocal’ was applied to those things which had both name and
definition in common. It is, therefore, established that in every
proposition, of which either substance or a differentia forms the
predicate, these are predicated univocally.
All substance appears to signify that which is individual. In the
case of primary substance this is indisputably true, for the
thing is a unit. In the case of secondary substances, when we
speak, for instance, of ‘man’ or ‘animal’, our form of speech
gives the impression that we are here also indicating that which
is individual, but the impression is not strictly true; for a
secondary substance is not an individual, but a class with a
certain qualification; for it is not one and single as a primary
substance is; the words ‘man’, ‘animal’, are predicable of more
than one subject.
Yet species and genus do not merely indicate quality, like the
term ‘white’; ‘white’ indicates quality and nothing further, but
species and genus determine the quality with reference to a
substance: they signify substance qualitatively differentiated.
The determinate qualification covers a larger field in the case
of the genus that in that of the species: he who uses the word
‘animal’ is herein using a word of wider extension than he who
uses the word ‘man’.
Another mark of substance is that it has no contrary. What could
be the contrary of any primary substance, such as the individual
man or animal? It has none. Nor can the species or the genus have
a contrary. Yet this characteristic is not peculiar to substance,
but is true of many other things, such as quantity. There is
nothing that forms the contrary of ‘two cubits long’ or of ‘three
cubits long’, or of ‘ten’, or of any such term. A man may contend
that ‘much’ is the contrary of ‘little’, or ‘great’ of ‘small’,
but of definite quantitative terms no contrary exists.
Substance, again, does not appear to admit of variation of
degree. I do not mean by this that one substance cannot be more
or less truly substance than another, for it has already been
stated’ that this is the case; but that no single substance
admits of varying degrees within itself. For instance, one
particular substance, ‘man’, cannot be more or less man either
than himself at some other time or than some other man. One man
cannot be more man than another, as that which is white may be
more or less white than some other white object, or as that which
is beautiful may be more or less beautiful than some other
beautiful object. The same quality, moreover, is said to subsist
in a thing in varying degrees at different times. A body, being
white, is said to be whiter at one time than it was before, or,
being warm, is said to be warmer or less warm than at some other
time. But substance is not said to be more or less that which it
is: a man is not more truly a man at one time than he was before,
nor is anything, if it is substance, more or less what it is.
Substance, then, does not admit of variation of degree.
The most distinctive mark of substance appears to be that, while
remaining numerically one and the same, it is capable of
admitting contrary qualities. From among things other than
substance, we should find ourselves unable to bring forward any
which possessed this mark. Thus, one and the same colour cannot
be white and black. Nor can the same one action be good and bad:
this law holds good with everything that is not substance. But
one and the selfsame substance, while retaining its identity, is
yet capable of admitting contrary qualities. The same individual
person is at one time white, at another black, at one time warm,
at another cold, at one time good, at another bad. This capacity
is found nowhere else, though it might be maintained that a
statement or opinion was an exception to the rule. The same
statement, it is agreed, can be both true and false. For if the
statement ‘he is sitting’ is true, yet, when the person in
question has risen, the same statement will be false. The same
applies to opinions. For if any one thinks truly that a person is
sitting, yet, when that person has risen, this same opinion, if
still held, will be false. Yet although this exception may be
allowed, there is, nevertheless, a difference in the manner in
which the thing takes place. It is by themselves changing that
substances admit contrary qualities. It is thus that that which
was hot becomes cold, for it has entered into a different state.
Similarly that which was white becomes black, and that which was
bad good, by a process of change; and in the same way in all
other cases it is by changing that substances are capable of
admitting contrary qualities. But statements and opinions
themselves remain unaltered in all respects: it is by the
alteration in the facts of the case that the contrary quality
comes to be theirs. The statement ‘he is sitting’ remains
unaltered, but it is at one time true, at another false,
according to circumstances. What has been said of statements
applies also to opinions. Thus, in respect of the manner in which
the thing takes place, it is the peculiar mark of substance that
it should be capable of admitting contrary qualities; for it is
by itself changing that it does so.
If, then, a man should make this exception and contend that
statements and opinions are capable of admitting contrary
qualities, his contention is unsound. For statements and opinions
are said to have this capacity, not because they themselves
undergo modification, but because this modification occurs in the
case of something else. The truth or falsity of a statement
depends on facts, and not on any power on the part of the
statement itself of admitting contrary qualities. In short, there
is nothing which can alter the nature of statements and opinions.
As, then, no change takes place in themselves, these cannot be
said to be capable of admitting contrary qualities.
But it is by reason of the modification which takes place within
the substance itself that a substance is said to be capable of
admitting contrary qualities; for a substance admits within
itself either disease or health, whiteness or blackness. It is in
this sense that it is said to be capable of admitting contrary
qualities.
To sum up, it is a distinctive mark of substance, that, while
remaining numerically one and the same, it is capable of
admitting contrary qualities, the modification taking place
through a change in the substance itself.
Let these remarks suffice on the subject of substance.
Quantity is either discrete or continuous. Moreover, some
quantities are such that each part of the whole has a relative
position to the other parts: others have within them no such
relation of part to part.
Instances of discrete quantities are number and speech; of
continuous, lines, surfaces, solids, and, besides these, time and
place.
In the case of the parts of a number, there is no common boundary
at which they join. For example: two fives make ten, but the two
fives have no common boundary, but are separate; the parts three
and seven also do not join at any boundary. Nor, to generalize,
would it ever be possible in the case of number that there should
be a common boundary among the parts; they are always separate.
Number, therefore, is a discrete quantity.
The same is true of speech. That speech is a quantity is evident:
for it is measured in long and short syllables. I mean here that
speech which is vocal. Moreover, it is a discrete quantity for
its parts have no common boundary. There is no common boundary at
which the syllables join, but each is separate and distinct from
the rest.
A line, on the other hand, is a continuous quantity, for it is
possible to find a common boundary at which its parts join. In
the case of the line, this common boundary is the point; in the
case of the plane, it is the line: for the parts of the plane
have also a common boundary. Similarly you can find a common
boundary in the case of the parts of a solid, namely either a
line or a plane.
Space and time also belong to this class of quantities. Time,
past, present, and future, forms a continuous whole. Space,
likewise, is a continuous quantity; for the parts of a solid
occupy a certain space, and these have a common boundary; it
follows that the parts of space also, which are occupied by the
parts of the solid, have the same common boundary as the parts of
the solid. Thus, not only time, but space also, is a continuous
quantity, for its parts have a common boundary.
Quantities consist either of parts which bear a relative position
each to each, or of parts which do not. The parts of a line bear
a relative position to each other, for each lies somewhere, and
it would be possible to distinguish each, and to state the
position of each on the plane and to explain to what sort of part
among the rest each was contiguous. Similarly the parts of a
plane have position, for it could similarly be stated what was
the position of each and what sort of parts were contiguous. The
same is true with regard to the solid and to space. But it would
be impossible to show that the arts of a number had a relative
position each to each, or a particular position, or to state what
parts were contiguous. Nor could this be done in the case of
time, for none of the parts of time has an abiding existence, and
that which does not abide can hardly have position. It would be
better to say that such parts had a relative order, in virtue of
one being prior to another. Similarly with number: in counting,
‘one’ is prior to ‘two’, and ‘two’ to ‘three’, and thus the parts
of number may be said to possess a relative order, though it
would be impossible to discover
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