by Aristotle
acting in a certain way: so that to be 'capable of being acted upon or
of acting' would be a property of 'being'.
Next, for destructive purposes, see if he has stated the property in
the superlative: for then what has been stated to be a property will
not be a property. For people who render the property in that way find
that of the object of which the description is true, the name is not
true as well: for though the object perish the description will
continue in being none the less; for it belongs most nearly to
something that is in being. An example would be supposing any one were
to render 'the lightest body' as a property of 'fire': for, though
fire perish, there eh re will still be some form of body that is the
lightest, so that 'the lightest body' could not be a property of fire.
For constructive purposes, on the other hand, see if he has avoided
rendering the property in the superlative: for then the property
will in this respect have been property of man has not rendered the
property correctly stated. Thus (e.g.) inasmuch as he in the
superlative, the property would in who states 'a naturally civilized
animal' as a this respect have been correctly stated.
Book VI
1
THE discussion of Definitions falls into five parts. For you have to
show either (1) that it is not true at all to apply the expression
as well to that to which the term is applied (for the definition of
Man ought to be true of every man); or (2) that though the object
has a genus, he has failed to put the object defined into the genus,
or to put it into the appropriate genus (for the framer of a
definition should first place the object in its genus, and then append
its differences: for of all the elements of the definition the genus
is usually supposed to be the principal mark of the essence of what is
defined): or (3) that the expression is not peculiar to the object
(for, as we said above as well, a definition ought to be peculiar): or
else (4) see if, though he has observed all the aforesaid cautions, he
has yet failed to define the object, that is, to express its
essence. (5) It remains, apart from the foregoing, to see if he has
defined it, but defined it incorrectly.
Whether, then, the expression be not also true of that of which
the term is true you should proceed to examine according to the
commonplace rules that relate to Accident. For there too the
question is always 'Is so and so true or untrue?': for whenever we
argue that an accident belongs, we declare it to be true, while
whenever we argue that it does not belong, we declare it to be untrue.
If, again, he has failed to place the object in the appropriate genus,
or if the expression be not peculiar to the object, we must go on to
examine the case according to the commonplace rules that relate to
genus and property.
It remains, then, to prescribe how to investigate whether the object
has been either not defined at all, or else defined incorrectly.
First, then, we must proceed to examine if it has been defined
incorrectly: for with anything it is easier to do it than to do it
correctly. Clearly, then, more mistakes are made in the latter task on
account of its greater difficulty. Accordingly the attack becomes
easier in the latter case than in the former.
Incorrectness falls into two branches: (1) first, the use of obscure
language (for the language of a definition ought to be the very
clearest possible, seeing that the whole purpose of rendering it is to
make something known); (secondly, if the expression used be longer
than is necessary: for all additional matter in a definition is
superfluous. Again, each of the aforesaid branches is divided into a
number of others.
2
One commonplace rule, then, in regard to obscurity is, See if the
meaning intended by the definition involves an ambiguity with any
other, e.g. 'Becoming is a passage into being', or 'Health is the
balance of hot and cold elements'. Here 'passage' and 'balance' are
ambiguous terms: it is accordingly not clear which of the several
possible senses of the term he intends to convey. Likewise also, if
the term defined be used in different senses and he has spoken without
distinguishing between them: for then it is not clear to which of them
the definition rendered applies, and one can then bring a captious
objection on the ground that the definition does not apply to all
the things whose definition he has rendered: and this kind of thing is
particularly easy in the case where the definer does not see the
ambiguity of his terms. Or, again, the questioner may himself
distinguish the various senses of the term rendered in the definition,
and then institute his argument against each: for if the expression
used be not adequate to the subject in any of its senses, it is
clear that he cannot have defined it in any sense aright.
Another rule is, See if he has used a metaphorical expression, as,
for instance, if he has defined knowledge as 'unsupplantable', or
the earth as a 'nurse', or temperance as a 'harmony'. For a
metaphorical expression is always obscure. It is possible, also, to
argue sophistically against the user of a metaphorical expression as
though he had used it in its literal sense: for the definition
stated will not apply to the term defined, e.g. in the case of
temperance: for harmony is always found between notes. Moreover, if
harmony be the genus of temperance, then the same object will occur in
two genera of which neither contains the other: for harmony does not
contain virtue, nor virtue harmony. Again, see if he uses terms that
are unfamiliar, as when Plato describes the eye as 'brow-shaded', or a
certain spider as poison-fanged', or the marrow as 'boneformed'. For
an unusual phrase is always obscure.
Sometimes a phrase is used neither ambiguously, nor yet
metaphorically, nor yet literally, as when the law is said to be the
'measure' or 'image' of the things that are by nature just. Such
phrases are worse than metaphor; for the latter does make its
meaning to some extent clear because of the likeness involved; for
those who use metaphors do so always in view of some likeness: whereas
this kind of phrase makes nothing clear; for there is no likeness to
justify the description 'measure' or 'image', as applied to the law,
nor is the law ordinarily so called in a literal sense. So then, if
a man says that the law is literally a 'measure' or an 'image', he
speaks falsely: for an image is something produced by imitation, and
this is not found in the case of the law. If, on the other hand, he
does not mean the term literally, it is clear that he has used an
unclear expression, and one that is worse than any sort of
metaphorical expression.
Moreover, see if from the expression used the definition of the
contrary be not clear; for definitions that have been correctly
rendered also indicate their contraries as well. Or, again, see if,
when it is merely stated by itself, it is not evi
dent what it defines:
just as in the works of the old painters, unless there were an
inscription, the figures used to be unrecognizable.
3
If, then, the definition be not clear, you should proceed to examine
on lines such as these. If, on the other hand, he has phrased the
definition redundantly, first of all look and see whether he has
used any attribute that belongs universally, either to real objects in
general, or to all that fall under the same genus as the object
defined: for the mention of this is sure to be redundant. For the
genus ought to divide the object from things in general, and the
differentia from any of the things contained in the same genus. Now
any term that belongs to everything separates off the given object
from absolutely nothing, while any that belongs to all the things that
fall under the same genus does not separate it off from the things
contained in the same genus. Any addition, then, of that kind will
be pointless.
Or see if, though the additional matter may be peculiar to the given
term, yet even when it is struck out the rest of the expression too is
peculiar and makes clear the essence of the term. Thus, in the
definition of man, the addition 'capable of receiving knowledge' is
superfluous; for strike it out, and still the expression is peculiar
and makes clear his essence. Speaking generally, everything is
superfluous upon whose removal the remainder still makes the term that
is being defined clear. Such, for instance, would also be the
definition of the soul, assuming it to be stated as a 'self-moving
number'; for the soul is just 'the self-moving', as Plato defined
it. Or perhaps the expression used, though appropriate, yet does not
declare the essence, if the word 'number' be eliminated. Which of
the two is the real state of the case it is difficult to determine
clearly: the right way to treat the matter in all cases is to be
guided by convenience. Thus (e.g.) it is said that the definition of
phlegm is the 'undigested moisture that comes first off food'. Here
the addition of the word 'undigested' is superfluous, seeing that 'the
first' is one and not many, so that even when undigested' is left
out the definition will still be peculiar to the subject: for it is
impossible that both phlegm and also something else should both be the
first to arise from the food. Or perhaps the phlegm is not
absolutely the first thing to come off the food, but only the first of
the undigested matters, so that the addition 'undigested' is required;
for stated the other way the definition would not be true unless the
phlegm comes first of all.
Moreover, see if anything contained in the definition fails to apply
to everything that falls under the same species: for this sort of
definition is worse than those which include an attribute belonging to
all things universally. For in that case, if the remainder of the
expression be peculiar, the whole too will be peculiar: for absolutely
always, if to something peculiar anything whatever that is true be
added, the whole too becomes peculiar. Whereas if any part of the
expression do not apply to everything that falls under the same
species, it is impossible that the expression as a whole should be
peculiar: for it will not be predicated convertibly with the object;
e.g. 'a walking biped animal six feet high': for an expression of that
kind is not predicated convertibly with the term, because the
attribute 'six feet high' does not belong to everything that falls
under the same species.
Again, see if he has said the same thing more than once, saying
(e.g.) 'desire' is a 'conation for the pleasant'. For 'desire' is
always 'for the pleasant', so that what is the same as desire will
also be 'for the pleasant'. Accordingly our definition of desire
becomes 'conation-for-the-pleasant': for the word 'desire' is the
exact equivalent of the words 'conation for-the-pleasant', so that
both alike will be 'for the pleasant'. Or perhaps there is no
absurdity in this; for consider this instance:-Man is a biped':
therefore, what is the same as man is a biped: but 'a walking biped
animal' is the same as man, and therefore walking biped animal is a
biped'. But this involves no real absurdity. For 'biped' is not a
predicate of 'walking animal': if it were, then we should certainly
have 'biped' predicated twice of the same thing; but as a matter of
fact the subject said to be a biped is'a walking biped animal', so
that the word 'biped' is only used as a predicate once. Likewise
also in the case of 'desire' as well: for it is not 'conation' that is
said to be 'for the pleasant', but rather the whole idea, so that
there too the predication is only made once. Absurdity results, not
when the same word is uttered twice, but when the same thing is more
than once predicated of a subject; e.g. if he says, like Xenocrates,
that wisdom defines and contemplates reality:' for definition is a
certain type of contemplation, so that by adding the words 'and
contemplates' over again he says the same thing twice over.
Likewise, too, those fail who say that 'cooling' is 'the privation
of natural heat'. For all privation is a privation of some natural
attribute, so that the addition of the word 'natural' is
superfluous: it would have been enough to say 'privation of heat', for
the word 'privation' shows of itself that the heat meant is natural
heat.
Again, see if a universal have been mentioned and then a
particular case of it be added as well, e.g. 'Equity is a remission of
what is expedient and just'; for what is just is a branch of what is
expedient and is therefore included in the latter term: its mention is
therefore redundant, an addition of the particular after the universal
has been already stated. So also, if he defines 'medicine' as
'knowledge of what makes for health in animals and men', or 'the
law' as 'the image of what is by nature noble and just'; for what is
just is a branch of what is noble, so that he says the same thing more
than once.
4
Whether, then, a man defines a thing correctly or incorrectly you
should proceed to examine on these and similar lines. But whether he
has mentioned and defined its essence or no, should be examined as
follows: First of all, see if he has failed to make the definition
through terms that are prior and more intelligible. For the reason why
the definition is rendered is to make known the term stated, and we
make things known by taking not any random terms, but such as are
prior and more intelligible, as is done in demonstrations (for so it
is with all teaching and learning); accordingly, it is clear that a
man who does not define through terms of this kind has not defined
at all. Otherwise, there will be more than one definition of the
same thing: for clearly he who defines through terms that are prior
and more intelligible has also framed a definition, and a better
one, so that both would then be definitions of the same object. This
sort of view, however, does not generally find acceptance: for of each
real object the essence is single: if, then, there are to be a
number of definitions of the same thing, the essence of the object
will be the same as it is represented to be in each of the
definitions, and these representations are not the same, inasmuch as
the definitions are different. Clearly, then, any one who has not
defined a thing through terms that are prior and more intelligible has
not defined it at all.
The statement that a definition has not been made through more
intelligible terms may be understood in two senses, either supposing
that its terms are absolutely less intelligible, or supposing that
they are less intelligible to us: for either sense is possible. Thus
absolutely the prior is more intelligible than the posterior, a point,
for instance, than a line, a line than a plane, and a plane than a
solid; just as also a unit is more intelligible than a number; for
it is the prius and starting-point of all number. Likewise, also, a
letter is more intelligible than a syllable. Whereas to us it
sometimes happens that the converse is the case: for the solid falls
under perception most of all-more than a plane-and a plane more than a
line, and a line more than a point; for most people learn things
like the former earlier than the latter; for any ordinary intelligence
can grasp them, whereas the others require an exact and exceptional
understanding.
Absolutely, then, it is better to try to make what is posterior
known through what is prior, inasmuch as such a way of procedure is
more scientific. Of course, in dealing with persons who cannot
recognize things through terms of that kind, it may perhaps be
necessary to frame the expression through terms that are
intelligible to them. Among definitions of this kind are those of a
point, a line, and a plane, all of which explain the prior by the
posterior; for they say that a point is the limit of a line, a line of
a plane, a plane of a solid. One must, however, not fail to observe