The Complete Aristotle (eng.)

knowledge.
<
    div id="section59" class="section" title="10">
10
    Moreover, see whether the like inflexions in the definition
apply to the like inflexions of the term; e.g. if ‘beneficial’
means ‘productive of health’, does ‘beneficially’ mean productively
of health’ and a ‘benefactor’ a ‘producer of health’?
    Look too and see whether the definition given will apply to the
Idea as well. For in some cases it will not do so; e.g. in the
Platonic definition where he adds the word ‘mortal’ in his
definitions of living creatures: for the Idea (e.g. the absolute
Man) is not mortal, so that the definition will not fit the Idea.
So always wherever the words ‘capable of acting on’ or ‘capable of
being acted upon’ are added, the definition and the Idea are
absolutely bound to be discrepant: for those who assert the
existence of Ideas hold that they are incapable of being acted
upon, or of motion. In dealing with these people even arguments of
this kind are useful.
    Further, see if he has rendered a single common definition of
terms that are used ambiguously. For terms whose definition
corresponding their common name is one and the same, are
synonymous; if, then, the definition applies in a like manner to
the whole range of the ambiguous term, it is not true of any one of
the objects described by the term. This is, moreover, what happens
to Dionysius’ definition of ‘life’ when stated as ‘a movement of a
creature sustained by nutriment, congenitally present with it’: for
this is found in plants as much as in animals, whereas ‘life’ is
generally understood to mean not one kind of thing only, but to be
one thing in animals and another in plants. It is possible to hold
the view that life is a synonymous term and is always used to
describe one thing only, and therefore to render the definition in
this way on purpose: or it may quite well happen that a man may see
the ambiguous character of the word, and wish to render the
definition of the one sense only, and yet fail to see that he has
rendered a definition common to both senses instead of one peculiar
to the sense he intends. In either case, whichever course he
pursues, he is equally at fault. Since ambiguous terms sometimes
pass unobserved, it is best in questioning to treat such terms as
though they were synonymous (for the definition of the one sense
will not apply to the other, so that the answerer will be generally
thought not to have defined it correctly, for to a synonymous term
the definition should apply in its full range), whereas in
answering you should yourself distinguish between the senses.
Further, as some answerers call ‘ambiguous’ what is really
synonymous, whenever the definition rendered fails to apply
universally, and, vice versa, call synonymous what is really
ambiguous supposing their definition applies to both senses of the
term, one should secure a preliminary admission on such points, or
else prove beforehand that so-and-so is ambiguous or synonymous, as
the case may be: for people are more ready to agree when they do
not foresee what the consequence will be. If, however, no admission
has been made, and the man asserts that what is really synonymous
is ambiguous because the definition he has rendered will not apply
to the second sense as well, see if the definition of this second
meaning applies also to the other meanings: for if so, this meaning
must clearly be synonymous with those others. Otherwise, there will
be more than one definition of those other meanings, for there are
applicable to them two distinct definitions in explanation of the
term, viz. the one previously rendered and also the later one.
Again, if any one were to define a term used in several senses,
and, finding that his definition does not apply to them all, were
to contend not that the term is ambiguous, but that even the term
does not properly apply to all those senses, just because his
definition will not do so either, then one may retort to such a man
that though in some things one must not use the language of the
people, yet in a question of terminology one is bound to employ the
received and traditional usage and not to upset matters of that
sort.
<
    div id="section60" class="section" title="11">
11
    Suppose now that a definition has been rendered of some complex
term, take away the definition of one of the elements in the
complex, and see if also the rest of the definition defines the
rest of it: if not, it is clear that neither