Return to Porphyry, Introduction
1. Difference, however, is predicated in common, peculiarly, and most peculiarly.
2. For one thing is said to differ from another in common, in consequence of differing in some respect or other, either from itself, or from something else. For Socrates differs from Plato, in being another person, and he differs from himself when a boy, and when he becomes a man, and when he does any thing, or ceases to do it. And Difference is always perceived in the various ways in which a thing is after a certain manner affected.
3. But one thing is said to differ peculiarly from another, when one thing differs from another by an inseparable Accident. And an inseparable Accident is such as an azure colour of the eye, crookedness of the nose, or a scar from a wound when it becomes scirrhous.
4. One thing also is said to differ most peculiarly from another, when it varies from it by a specific Difference. Thus, man differs from horse by a specific Difference, viz. by the quality of rational.
5. Universally, therefore, every Difference, when connected with anything, causes that thing to be altered. But Differences which subsist in common and peculiarly, cause a thing to be different in quality: and Differences which are most peculiar, cause one thing to be another thing.
6. Hence, those Differences which cause it to be another thing, are called specific Differences; but those which cause it to be changed in quality, are simple Differences. For the Difference of rational acceding to animal, causes it to be another thing, and makes it to be a Species of animal; but the Difference of being moved makes it to differ in quality alone from that which is at rest. Hence, the one makes it to be another thing, but the other only makes it to be different in quality.
7. According to specific Differences therefore, which cause a thing to be another thing, the divisions of Genera into Species are produced, and the definitions are assigned, which consist from Genus and Differences of this kind. But according to those Differences which alone cause a thing to be different in quality, alterations alone are constituted, and the mutations of that which subsists after a certain manner.
8. Beginning therefore again, we must say, that of Differences some are separable, but others inseparable. For to be moved, and to be at rest, to be ill, and to be well, and such things as are similar to these, are separable Differences; but to have a crooked, or a flat nose, to be rational or irrational, are inseparable Differences.
9. Of inseparable Differences too, some subsist essentially, but others from Accident. Thus, rational, mortal, and to be capable of receiving science, are essentially inherent in man; but to have a crooked or a flat nose, are inherent from Accident, and not essentially.
10. The Differences therefore, which are essentially present, are assumed in the definition of Essence, and make a thing to be another thing; but those which are from Accident, are neither assumed in the definition of Essence, nor make a thing to be another thing, but cause it to be different in quality.
11. And those Differences indeed, which are essential, do not admit of the more and the less; but those which are from Accident, though they should be inseparable, admit of intension and remission. For neither is Genus more and less predicated of that of which it is the Genus, nor the Differences of Genus according to which it is divided. For these are the things which give completion to the definition of every thing. But the Essence of every thing is one and the same, and neither admits of intension nor remission. To have a crooked or a flat nose however, or to be after a certain manner coloured, admit of intension and remission.
12. Since therefore, three Species of Difference are beheld; and some indeed are separable, but others inseparable; and, of the inseparable some are essential, but others from Accident; again, of essential Differences, some are those according to which we divide Genera into Species; but others are those according to which the things divided become specific. Thus, with respect to such Differences of animal as the following; viz. animated and sensitive, rational and irrational, mortal and immortal; the Difference of animated and sensitive is constitutive of the Essence of animal; but the Difference of mortal and immortal, and also of rational and irrational, are the divisive Differences of animal; for through these we divide Genera into Species.
13. These divisive Differences however of Genera, give completion to, and constitute Species. For animal is divided by the Difference of rational and irrational, and again, by the Difference of mortal and immortal; but the Differences of rational and mortal, become constitutive of man; those of rational and immortal, of a God; and those of mortal and irrational, of irrational animals. Thus, also, since the Differences, animated and inanimate, sensitive and deprived of sense, divide Essence or substance, which is arranged in the highest place; animated and sensitive added to Essence, form animal; but animated and deprived of sense, form plant.
14. Since, therefore, the same Differences assumed in a certain respect, become constitutive; and in a certain respect become divisive; all of them are called specific.
15. And these are especially useful in the divisions of Genera, and in definitions; but this is not the case with Differences which are inseparable from Accident, and much less with those that are separable.
16. These also defining, they say Difference is that by which Species is more abundant than Genus. Thus, man has more than animal in consequence of being rational and mortal. For animal is neither any. one of these (since if it were, whence, would Species have Differences?) nor has it all opposite Differences; (because if it had, the same thing would at the same time have opposites) but as they conceive, it contains in capacity all the Differences which are under it) but possesses no one of them in energy. And thus, neither is any thing Generated from non-entities, nor will opposites subsist at once about the same thing.
17. They also define Difference as follows: Difference is that which is predicated of many things differing in Species, in answer to the question “What kind of a thing is this?”. Thus, rational and mortal, when predicated of man, are predicated in answer to the question, “What kind of a thing is man?”, and not in answer to the question, “What is man?”. For being asked “What is man?”, we appropriately answer, “an animal”; but when we are asked, “What kind of an animal is man?”, we properly reply, that “He is a rational and mortal animal.”. For since things consist from matter and form, or from things which are analogous to matter and form, as a statue is composed from brass, as matter, but from figure, as form; Thus, also man, both the common and specific consists from Genus which is analogous to matter, and from Difference which is analogous to form. This whole however, viz. animal rational mortal, is man, in the same manner as the statue there.
18. They also describe it as follows: Difference is that which is naturally adapted to separate things which are arranged under the same Genus. Thus, rational and irrational, separate man and horse, which are under the same Genus, viz. animal.
19. They likewise explain it thus: Difference is that by which every thing differs. For man and horse, do not indeed differ according to Genus; for both we and horses are animals; but the addition of rational separates us from them. We also and angels are rational, but the addition of mortal separates us from them.
20. Those however who more elegantly discuss what pertains to Difference, do not say that Difference is any thing casual which separates things under the same Genus, but they assert it to be that which contributes to the Essence and the very nature of a tiling, and which is a part of a thing. Thus, to be naturally adapted to sail is not the Difference of man, though it is the Peculiarity of man. For we may say, that of animals some are naturally adapted to sail, and others are not; separating man from other animals. But a natural ability of sailing, does not give completion to the Essence of man, nor is a part of his Essence, but is alone an aptitude of it; because it is not such a Difference, as those are which are called specific Differences. Hence, specific Differences will be those, which produce another Species, and which are assumed in explaining in what the very nature of a thing consists.
21. Thus, much may suffice concerning Difference.
Return to Porphyry, Introduction
The lessons published on this site are freely available to read. If you wish to move from reading to formal study — with graded assessments, academic records, and the support of the Academy — you may enroll at any time. Enrollment is open year round, to students of all ages.
