Page - 253 - in The Complete Aristotle

happens in the case of inanimate things. Clearly, also, the species, in the instances given, has a wider denotation than the genus, whereas it ought to be vice versa. Again, see whether he has placed the differentia inside the species, by taking (e.g.) ‘immortal’ to be ‘a god’. For the result will be that the species has an equal or wider denotation: and this cannot be, for always the differentia has an equal or a wider denotation than the species. Moreover, see whether he has placed the genus inside the differentia, by making ‘colour’ (e.g.) to be a thing that ‘pierces’, or ‘number’ a thing that is ‘odd’. Also, see if he has mentioned the genus as differentia: for it is possible for a man to bring forward a statement of this kind as well, e.g. that ‘mixture’ is the differentia of ‘fusion’, or that change of place’ is the differentia of ‘carriage’. All such cases should be examined by means of the same principles: for they depend upon common rules: for the genus should have a wider denotation that its differentia, and also should not partake of its differentia; whereas, if it be rendered in this manner, neither of the aforesaid requirements can be satisfied: for the genus will both have a narrower denotation than its differentia, and will partake of it. Again, if no differentia belonging to the genus be predicated of the given species, neither will the genus be predicated of it; e.g. of ‘soul’ neither ‘odd’ nor ‘even’ is predicated: neither therefore is ‘number’. Moreover, see whether the species is naturally prior and abolishes the genus along with itself: for the contrary is the general view. Moreover, if it be possible for the genus stated, or for its differentia, to be absent from the alleged species, e.g. for ‘movement’ to be absent from the ‘soul’, or ‘truth and falsehood’ from ‘opinion’, then neither of the terms stated could be its genus or its differentia: for the general view is that the genus and the differentia accompany the species, as long as it exists. < div id=“section38” class=“section” title=“3”> 3 Look and see, also, if what is placed in the genus partakes or could possibly partake of any contrary of the genus: for in that case the same thing will at the same time partake of contrary things, seeing that the genus is never absent from it, while it partakes, or can possibly partake, of the contrary genus as well. Moreover, see whether the species shares in any character which it is utterly impossible for any member of the genus to have. Thus (e.g.) if the soul has a share in life, while it is impossible for any number to live, then the soul 253