It is this definitely rational tone that constitutes the differentia of the teaching of the sages.
17-25): definition (6pos), genus (yEvos), differentia (b&a40pa), property (i&eov), accident (avµ(3e(3771c6s).
(3) Differentia is that part of the essence which distinguishes one species from another.
This classification, though it is of high value in the clearing up of our conceptions of the essential contrasted with the accidental, the relation of genus, differentia and definition and so forth, is of more significance in connexion with abstract sciences, especially mathematics, than for the physical sciences.
Henceforth a significant differentia Gratian.
To quote the differentia of Sir Oliver Lodge: "A solid has volume and shape; a liquid has volume, but no shape; a gas has neither volume nor shape."
In this irreversible catena proceeding from ground to consequent, we have left far behind such things as the formal parity of genus and differentia considered as falling under the same predicable, 3 and hence justified in part Porphyry's divergence from the scheme of predicables.