PORPHYRY'S INTRODUCTION.

Each of these original: "each of these" consists of properties, the sum of which could never exist in any other of the particulars; the properties of Socrates could not be the same in any other of the particulars. However, the properties of Man (I mean the common one) could be the same in many, or rather in all of the particular men, insofar as they are men. It contains the individual under the species, and the species under the genus. For the genus is a whole, the individual is a part, and the species is both a whole and a part; but it is a part of one thing and a whole of another, and it is in others. The whole is in the parts. Thus, regarding genus and species, whether the most generic or the most specific, or which are the same as genera and species, or which are the individuals, or in how many ways genus and species are spoken of, it has been said.

3 A difference is spoken of commonly, properly, and most properly. Commonly, one thing is said to differ from another if it is distinguished by otherness in any way, either from itself or from another. Socrates differs from Plato by otherness, and he differs from himself as a child versus a grown man, or when active versus when resting; he is always viewed in the otherness of his conditions. Properly, one thing is said to differ from another when it differs from the other by an inseparable accident. An inseparable accident is such as blue eyes, a hooked nose, or a scar resulting from a wound. Most properly, one thing is said to differ from another when it is distinguished by a specific difference, just as man differs from horse by the specific difference of being "rational" and "mortal." Generally, every difference, when added to something, makes it something else. But those spoken of commonly and properly make it "different" meaning: altered in quality, while those spoken of most properly make it "another" meaning: a different kind of thing. Of differences, some make it "different" and others make it "another." Those that make it "another" are called specific differences, while those that make it "different" are simple differences. When the difference "rational" is added to "animal," it makes it "another" by making it a species; but when "moving" is added, it only makes it "different" compared to "resting," so that in one case it made it "another," and in the other only "different." Divisions of genera into species are made by the differences that make it "another," and definitions are rendered from the genus and these differences. But the differences that only make it "different" constitute only othernesses and changes in condition. We must start again from the beginning and say that differences are either separable or inseparable. Those such as "moving" and "resting," or "being healthy" and "being sick," and similar things, are separable. Being "hooked-nosed" or "snub-nosed," or "rational" or "irrational," are inseparable. Of the inseparable ones, some exist essentially, others by accident. For example, "rational" exists essentially in man, as does "mortal" and "capable of science," while being "hooked-nosed" or "snub-nosed" is an accident, not essential. Those that are present essentially are taken into the account of the substance and make it "another," while those that are accidental are neither taken into the account of the substance nor make it "another," but only "different." And those that are essential admit of the "more" and "less," whereas the accidental ones, even if they are inseparable, admit of intensification and remission; when the genus is predicated more or less, it is because of the differences of the genus, by which it is divided. For these are the ones that complete the account of the substance, and for each thing, the same thing admits of remission and intensification,

while being snub-nosed or hooked-nosed, or having a certain color, admits of intensification and remission. Since three kinds of difference are observed—some being separable, some inseparable, and again among the inseparable ones, some are essential and some are accidental—and again, among the essential differences, some are those by which we divide genera into species, and others are those by which the divided things are specified. For example, of all these essential differences, "animal" consists of animate and sensory, rational and irrational, mortal and immortal. Animate and sensory is a constitutive difference of the substance of "animal," from which "animal" is an animate, sensory substance. The difference of mortal and immortal, as well as rational and irrational, are divisive differences of the animal; for through them we divide genera into species. But these divisive differences of the genera become complementary and constitutive of the species; for it divides "animal" by the rational and irrational difference, and again by the mortal and immortal difference. But the rational and mortal differences become constitutive of man, the rational and immortal of God, and the mortal and irrational of the irrational animals. Thus, those that are highest among the divisive substances of the animate and inanimate difference, and of the sensory and non-sensory, when taken as animate and sensory, completed the "animal" when added to the substance, while when taken as animate and non-sensory, they completed the "plant." Since, therefore, the same things, when taken in one way, become constitutive, and in another way, divisive, they are all called specific. These are needed most for the divisions of genera and for definitions, but not for the accidental inseparable ones, and even less for the separable ones. As those who define it say, a difference is that by which the species exceeds the genus. For the man has more than the animal: the rational and the mortal. But the animal is none of these; otherwise, where would the species get the differences? But it possesses them all, not because it has contradictory things at the same time, but as it claims, it has all the differences of those under it in potentiality, but none in actuality. Thus, when something comes to be from things that exist, the opposites will not be around the same things at the same time. Defining it this way, a difference is that which is predicated of several things differing in species in the "what kind of thing it is." "Rational" and "mortal" are predicated of man in the "what kind of thing is man," not in the "what it is." For if we are asked what man is, it is appropriate to say "animal," but if we are asked what kind of animal, we will appropriately respond "rational and mortal." For of things that consist of matter and form, and have their composition analogous to matter and form—just as a statue consists of matter in the bronze and form in the shape—so the common and specific man consists of matter analogous to the genus, and from the form of the difference. The whole of this, "rational mortal animal," is the man, just as the statue is there. They define it thus: a difference is that which is naturally suited to separate things under the same genus. "Rational" and "irrational" separate man and horse, which are under the same genus, "animal." They render it thus: a difference is how each differs. Man and horse differ by the genus; we are animals,