Return to Porphyry, Introduction
1. Genus and Species possess in common, as we have said, the being predicated of many things.
2. Species however must be assumed as Species only, and not also as Genus, if the same thing should be both Genus and Species.
3. It is likewise common to them to be prior to the things of which they are predicated.
4. And also that each of them is a certain whole.
5. They differ however, because Genus indeed comprehends Species, but Species are comprehended, and do not comprehend Genera.
6. For Genus is predicated to a greater extent than Species.
7. Again, it is necessary that Genera should be pre-supposed, and when invested with form by specific Differences, that they should give consummation to Species.
8. Whence also Genera are prior by nature.
9. They also subvert other things together with themselves, but are not co-subverted with other things.
10. Thus, Species existing, Genus also entirely exists; but Genus existing, it does not entirely follow that Species exists.
11. And Genera indeed, are synonymously predicated of the Species which are under them; but Species are not; thus, predicated of Genera.
12. Farther still, Genera are more copious than Species, in consequence of comprehending the Species which are under them; but Species are more copious than Genera by their proper Differences.
13. Again, neither Species can become most General, nor Genus most specific.
Return to Porphyry, Introduction
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