Aristotle - The Organon - index for TOPICA Book 4 Part 6

If the term rendered fails to be the genus of anything

Paragraph 1 Moreover, see whether the term rendered fail to be the genus of anything at all;
Paragraph 2 Again, see whether he has named as genus or differentia some feature that goes with everything:
Paragraph 3 Moreover, see if the description 'inherent in S' be used of the genus rendered in relation to its species, as it is used of 'white' in the case of snow, thus showing clearly that it could not be the genus:
Paragraph 4 Moreover, beware, whenever both species and genus have a contrary, and he places the better of the contraries inside the worse genus:
Paragraph 5 Moreover, judge by means of greater and less degrees:
Paragraph 6 Again, if what is more generally, or as generally, thought to be the genus be not so, clearly neither is the genus rendered.
Paragraph 7 In demolishing a view, therefore, you should follow the rule as stated.
Paragraph 8 Moreover, to establish a view, you should look and see if the genus is predicated in the category of essence of those things of which it has been rendered as the genus, supposing the species rendered to be not one single species but several different ones:
Paragraph 9 Since some people think that the differentia, too, is a predicate of the various species in the category of essence, you should distinguish the genus from the differentia by employing the aforesaid elementary principles - (a) that the genus has a wider denotation than the differentia;
Paragraph 10 The differentia, then, should be distinguished from the genus in this manner.
Paragraph 11 Moreover, seeing that it is difficult to distinguish whatever always follows along with a thing, and is not convertible with it, from its genus, if A follows B universally, whereas B does not follow A universally - as e.g. 'rest' always follows a 'calm' and 'divisibility' follows 'number', but not conversely (for the divisible is not always a number, nor rest a calm) - you may yourself assume in your treatment of them that the one which always follows is the genus, whenever the other is not convertible with it:

UPHOME HTML by RBJ created 1996/11/25 modified 2009/04/26