The Complete Aristotle (eng.)

in the same relation as well, e.g. in relation to medical
treatment (for a man may exhibit both daring and right reasoning in
respect of medical treatment), still, none the less, not even this
combination of ‘the one+the other ‘makes him ‘courageous’. For the
two must not relate to any casual object that is the same, any more
than each to a different object; rather, they must relate to the
function of courage, e.g. meeting the perils of war, or whatever is
more properly speaking its function than this.
    Some definitions rendered in this form fail to come under the
aforesaid division at all, e.g. a definition of anger as ‘pain with
a consciousness of being slighted’. For what this means to say is
that it is because of a consciousness of this sort that the pain
occurs; but to occur ‘because of’ a thing is not the same as to
occur ‘+ a thing’ in any of its aforesaid senses.
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14
    Again, if he have described the whole compounded as the
‘composition’ of these things (e.g. ‘a living creature’ as a
‘composition of soul and body’), first of all see whether he has
omitted to state the kind of composition, as (e.g.) in a definition
of ‘flesh’ or ‘bone’ as the ‘composition of fire, earth, and air’.
For it is not enough to say it is a composition, but you should
also go on to define the kind of composition: for these things do
not form flesh irrespective of the manner of their composition, but
when compounded in one way they form flesh, when in another, bone.
It appears, moreover, that neither of the aforesaid substances is
the same as a ‘composition’ at all: for a composition always has a
decomposition as its contrary, whereas neither of the aforesaid has
any contrary. Moreover, if it is equally probable that every
compound is a composition or else that none is, and every kind of
living creature, though a compound, is never a composition, then no
other compound could be a composition either.
    Again, if in the nature of a thing two contraries are equally
liable to occur, and the thing has been defined through the one,
clearly it has not been defined; else there will be more than one
definition of the same thing; for how is it any more a definition
to define it through this one than through the other, seeing that
both alike are naturally liable to occur in it? Such is the
definition of the soul, if defined as a substance capable of
receiving knowledge: for it has a like capacity for receiving
ignorance.
    Also, even when one cannot attack the definition as a whole for
lack of acquaintance with the whole, one should attack some part of
it, if one knows that part and sees it to be incorrectly rendered:
for if the part be demolished, so too is the whole definition.
Where, again, a definition is obscure, one should first of all
correct and reshape it in order to make some part of it clear and
get a handle for attack, and then proceed to examine it. For the
answerer is bound either to accept the sense as taken by the
questioner, or else himself to explain clearly whatever it is that
his definition means. Moreover, just as in the assemblies the
ordinary practice is to move an emendation of the existing law and,
if the emendation is better, they repeal the existing law, so one
ought to do in the case of definitions as well: one ought oneself
to propose a second definition: for if it is seen to be better, and
more indicative of the object defined, clearly the definition
already laid down will have been demolished, on the principle that
there cannot be more than one definition of the same thing.
    In combating definitions it is always one of the chief
elementary principles to take by oneself a happy shot at a
definition of the object before one, or to adopt some correctly
expressed definition. For one is bound, with the model (as it were)
before one’s eyes, to discern both any shortcoming in any features
that the definition ought to have, and also any superfluous
addition, so that one is better supplied with lines of attack.
    As to definitions, then, let so much suffice.

Topics, Book VII
    Translated by W. A. Pickard-Cambridge
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    1
    Whether two things are ‘the same’ or ‘different’, in the most
literal of the meanings ascribed to ‘sameness’ (and we said’ that
‘the same’ applies in the most literal sense to what is numerically
one), may be examined in the light of their inflexions