The Complete Aristotle (eng.)

are
not so, and for constructive purposes, whether they are so. Of the
terms not being more intelligible, one test is to see whether the
property which he renders is altogether more unintelligible than
the subject whose property he has stated: for, if so, the property
will not have been stated correctly. For the object of getting a
property constituted is to be intelligible: the terms therefore in
which it is rendered should be more intelligible: for in that case
it will be possible to conceive it more adequately, e.g. any one
who has stated that it is a property of ‘fire’ to ‘bear a very
close resemblance to the soul’, uses the term ‘soul’, which is less
intelligible than ‘fire’-for we know better what fire is than what
soul is-, and therefore a ‘very close resemblance to the soul’
could not be correctly stated to be a property of fire. Another
test is to see whether the attribution of A (property) to B
(subject) fails to be more intelligible. For not only should the
property be more intelligible than its subject, but also it should
be something whose attribution to the particular subject is a more
intelligible attribution. For he who does not know whether it is an
attribute of the particular subject at all, will not know either
whether it belongs to it alone, so that whichever of these results
happens, its character as a property becomes obscure. Thus (e.g.) a
man who has stated that it is a property of fire to be ‘the primary
element wherein the soul is naturally found’, has introduced a
subject which is less intelligible than ‘fire’, viz. whether the
soul is found in it, and whether it is found there primarily; and
therefore to be ‘the primary element in which the soul is naturally
found’ could not be correctly stated to be a property of ‘fire’. On
the other hand, for constructive purposes, see whether the terms in
which the property is stated are more intelligible, and if they are
more intelligible in each of the aforesaid ways. For then the
property will have been correctly stated in this respect: for of
constructive arguments, showing the correctness of a rendering,
some will show the correctness merely in this respect, while others
will show it without qualification. Thus (e.g.) a man who has said
that the ‘possession of sensation’ is a property of ‘animal’ has
both used more intelligible terms and has rendered the property
more intelligible in each of the aforesaid senses; so that to
‘possess sensation’ would in this respect have been correctly
rendered as a property of ‘animal’.
    Next, for destructive purposes, see whether any of the terms
rendered in the property is used in more than one sense, or whether
the whole expression too signifies more than one thing. For then
the property will not have been correctly stated. Thus (e.g.)
seeing that to ‘being natural sentient’ signifies more than one
thing, viz. (1) to possess sensation, (2) to use one’s sensation,
being naturally sentient’ could not be a correct statement of a
property of ‘animal’. The reason why the term you use, or the whole
expression signifying the property, should not bear more than one
meaning is this, that an expression bearing more than one meaning
makes the object described obscure, because the man who is about to
attempt an argument is in doubt which of the various senses the
expression bears: and this will not do, for the object of rendering
the property is that he may understand. Moreover, in addition to
this, it is inevitable that those who render a property after this
fashion should be somehow refuted whenever any one addresses his
syllogism to that one of the term’s several meanings which does not
agree. For constructive purposes, on the other hand, see whether
both all the terms and also the expression as a whole avoid bearing
more than one sense: for then the property will have been correctly
stated in this respect. Thus (e.g.) seeing that ‘body’ does not
bear several meanings, nor quickest to move upwards in space’, nor
yet the whole expression made by putting them together, it would be
correct in this respect to say that it is a property of fire to be
the ‘body quickest to move upwards in space’.
    Next, for destructive purposes, see if the term of which he
renders the property is used in more than one sense, and no
distinction has been drawn as to which of them it is whose property
he is stating: for then the property will not have been