Clement of Alexandria · a new plain-English translation from the original language
We must first put forward, from among definitions and demonstrations and divisions, how many ways the thing sought is spoken of, and the homonymous terms must be handled and the synonymous terms clearly arranged according to their meanings. Next it must be inquired whether the subject before us belongs to the class of things considered in relation to other things, or is taken by itself. After this comes: whether it is, what it is, what belongs to it, or alternatively: whether it exists, what it is, on account of what it is so. For the contemplation of these things, both the knowledge of particulars and the knowledge of universals contribute, and prior knowledge, and the divisions made according to the differences of these things. Induction, then, brings the universal and the definition, and the divisions bring the species and the essence and the individual, while the contemplation of the many senses in which a thing is said brings the grasp of what is proper to it; and the puzzling-out of difficulties increases the differences arising from these, and the demonstrations, and the contemplation itself in other ways, together with what accompanies it. From all these together, knowledge and truth are established. Again, what is summed up from the division becomes a definition; for the determination is taken both prior to the division and posterior to it — prior, when it is conceded or set forth as a premise, posterior, when it has been demonstrated. And likewise by way of sense-perception, the particular yields up the universal in summary; for sense-perception is where induction begins, and it ends in the universal. Induction, then, does not reveal what something is, only that it exists or does not; division discloses its nature. The determination, likewise with division, teaches the substance and what a thing is, but not whether it is; while demonstration makes clear all three — whether it is, what it is, and why it is. And there are some definitions that also embrace the cause.
Since to know scientifically is to have seen the cause, and the causes are four — matter, the moving cause, the form, and the end — the determination will accordingly be fourfold. First one must adopt the genus — within it lie the things immediately above — and after that, the nearest difference. And the continuous series of differences, being cut and divided off, fills out the essence. It is not necessary to state all the differences of each thing, but only those that make the species. Geometrical analysis and synthesis resemble dialectical division and definition; and from division we run back up to the simpler and more elementary things. The genus of the thing sought, at any rate, we divide into the species contained in it — take man, for example: animal, the genus, we split into its contained species, mortal and immortal, and so, always cutting the things that seem to be composite genera into simpler species, we arrive at the thing sought, which no longer admits of cutting. For having divided animal into mortal and immortal, then again mortal into land-dwelling and water-dwelling, and again land-dwelling into winged and footed — and so, dividing the species that comes nearest to the thing sought, which also embraces the thing sought, we shall arrive, by cutting, at the simplest species, which embraces nothing else but the thing sought alone. For again we divide the footed into rational and irrational; and then, choosing out the species nearest to man from among those taken by division, and putting them together into a single account, we render the definition of man, which is: a mortal animal, land-dwelling, footed, rational.
Hence division holds the place of matter for the definition, seeking the simplicity proper to the name, while the definition holds the place of the craftsman and maker, putting together and constructing and setting forth the knowledge of the thing that is. Definitions belong neither to the things themselves nor to the ideas, but rather we say that of those things of which we have universal conceptions, the definitions are the interpretive accounts of these conceptions; for it is of these conceptions that the divisions also come to be. Of divisions, one divides the thing divided into species as a genus; another divides it into parts as a whole; another divides it into accidents. The division of the whole into parts is conceived for the most part according to magnitude, while the division into accidents can never be taken as complete, if indeed substance must belong altogether to each of the things that are. Hence both these divisions are disreputable, and only the cutting of genus into species is reputable, by which both the identity according to genus and the difference according to the specific differences are marked out. The species is always seen within some part, but not conversely — if something is a part of something, this will not necessarily also be a species. For a hand belongs to man as a part, yet counts as no species. And the genus is present within the species — for animal is found both in man and in ox — but the whole does not exist within the parts, for man does not exist within his feet. Hence the species is more properly so called than the part. And whatever is predicated of the genus, all this will also be predicated of the species.
The genus, then, is best split into two species, or failing that, into three. Now when the species undergo the more generic division, sameness and otherness mark them out; and then, when divided by way of the things signified generically, they are characterized accordingly. For each of the species is either substance (as when we say: of things that are, some are bodies, others are incorporeal) or quantity or quality or relation or place or time or position or possession or action or being-acted-upon. Whoever has scientific knowledge of anything whatsoever will also be able to render its definition, since one who is unable to grasp and define anything in an account could never have scientific knowledge of it. And it is from ignorance of definition that many disputes and deceptions come to arise. For if one who knows a thing has knowledge of it in his understanding, and is also able to make clear in speech what he understands, and the interpretation of the understanding is a definition, then it is necessary that one who knows the thing should also be able to render its definition.
Definitions also take on, in addition, the difference, which holds for the definition the place of a distinguishing mark. To the definition of man, for instance, the addition of "capable of laughter" makes the whole: a rational, mortal, land-dwelling, footed, laughter-capable animal. For the marks added to a definition according to difference belong properly to the things in question, but do not indicate the nature of the things themselves. At once they say that the rendering of what is proper is the difference; and since whatever bears the difference stands apart from everything else — the difference belonging to it alone and being counter-predicated of the thing in definitions — it is necessary to take the first genus as a starting-point and as underlying subject. In the longer definitions, then, is found the multitude of species discovered through the ten categories, while in the shortest ones the foremost of the proximate species taken together indicate the substance and nature of the thing; and the shortest definition is composed of three elements, the genus and two of the most necessary species. This happens for brevity's sake: thus we state that man is a laughter-capable, rational animal. And whatever belongs distinctively to the thing being defined must also be taken in addition — either its proper virtue or its proper function or certain other such things. The definition, then, being explanatory of the substance of the thing, is unable to grasp with precision the nature of the thing, but makes its disclosure of the substance through the most proper species, and the definition holds the substance, so to speak, within a quality.
← All of Clement of Alexandria: Exhortation, Instructor & Miscellanies