(21) The claim of Motion to be established as a genus will depend upon three conditions: first, that it cannot rightly be referred to any other genus; second, that nothing higher than itself can be predicated of it in respect of its essence; third, that by assuming differences it will produce species. These conditions satisfied, we may consider the nature of the genus to which we shall refer it.

Clearly it cannot be identified with either the Substance or the Quality of the things which possess it. It cannot, further, be consigned to Action, for Passivity also comprises a variety of motions; nor again to Passivity itself, because many motions are actions: on the contrary, actions and passions are to be referred to Motion.

Furthermore, it cannot lay claim to the category of Relation on the mere ground that it has an attributive and not a self-centred existence: on this ground, Quality too would find itself in that same category; for Quality is an attribute and contained in an external: and the same is true of Quantity.

If we are agreed that Quality and Quantity, though attributive, are real entities, and on the basis of this reality distinguishable as Quality and Quantity respectively: then, on the same principle, since Motion, though an attribute has a reality prior to its attribution, it is incumbent upon us to discover the intrinsic nature of this reality. We must never be content to regard as a relative something which exists prior to its attribution, but only that which is engendered by Relation and has no existence apart from the relation to which it owes its name: the double, strictly so called, takes birth and actuality in juxtaposition with a yard's length, and by this very process of being juxtaposed with a correlative acquires the name and exhibits the fact of being double.

What, then, is that entity, called Motion, which, though attributive, has an independent reality, which makes its attribution possible- the entity corresponding to Quality, Quantity and Substance?

But first, perhaps, we should make sure that there is nothing prior to Motion and predicated of it as its genus.

Change may be suggested as a prior. But, in the first place, either it is identical with Motion, or else, if change be claimed as a genus, it will stand distinct from the genera so far considered: secondly, Motion will evidently take rank as a species and have some other species opposed to it- becoming, say- which will be regarded as a change but not as a motion.

What, then, is the ground for denying that becoming is a motion? The fact, perhaps, that what comes to be does not yet exist, whereas Motion has no dealings with the non-existent. But, on that ground, becoming will not be a change either. If however it be alleged that becoming is merely a type of alteration or growth since it takes place when things alter and grow, the antecedents of becoming are being confused with becoming itself. Yet becoming, entailing as it does these antecedents, must necessarily be a distinct species; for the event and process of becoming cannot be identified with merely passive alteration, like turning hot or white: it is possible for the antecedents to take place without becoming as such being accomplished, except in so far as the actual alteration has "come to be"; where, however, an animal or a vegetal life is concerned, becoming takes place only upon its acquisition of a Form.

The contrary might be maintained: that change is more plausibly ranked as a species than is Motion, because change signifies merely the substitution of one thing for another, whereas Motion involves also the removal of a thing from the place to which it belongs, as is shown by locomotion. Even rejecting this distinction, we must accept as types of Motion knowledge and musical performance- in short, changes of condition: thus, alteration will come to be regarded as a species of Motion- namely, motion displacing.

(1) With respect to your inquiry, “ what the peculiarities are in each of the more excellent genera, by which they are separated from each other? ” if you understand by peculiarities the specific differences under the same genus, which are distinguished by opposite qualities, as the rational and irrational under animal; we by no means admit peculiarities of this kind, in things which neither have one common essence, nor an equal contradistinction, nor receive a composition from something common, which is indefinite, and defines the peculiarity. But if you apprehend the peculiarity to be, as in prior and secondary natures, differing in their whole essence and whole genus, a certain simple condition of being, definite in itself; in this case, your conception of peculiarities will be reasonable. For these peculiarities of things, which have an eternal subsistence, are simple, and entirely exempt. The inquiry, however, proceeds imperfectly. For it was necessary, in the first place, to inquire what the peculiarities are of the more excellent genera, according to essence; in the next place, what they are according to power; and thus afterwards, what they are according to energy.

(1) Now every single class of living thing, Asclepius, of whatsoever kind, or it be mortal or be rational, whether it be endowed with soul, or be without one, just as each has its class, so does each several [class] have images of its own class. And though each separate class of animal has in it every form of its own class, still in the selfsame [kind of] form the units differ from each other. And so although the class of men is of one kind, so that a man can be distinguished by his [general] look, still individual men within the sameness of their [common] form do differ from each other.

(19) Having established our four primary genera, it remains for us to enquire whether each of them of itself alone produces species. And especially, can Being be divided independently, that is without drawing upon the other genera? Surely not: the differentiae must come from outside the genus differentiated: they must be differentiae of Being proper, but cannot be identical with it.

Where then is it to find them? Obviously not in non-beings. If then in beings, and the three genera are all that is left, clearly it must find them in these, by conjunction and couplement with these, which will come into existence simultaneously with itself.

But if all come into existence simultaneously, what else is produced but that amalgam of all Existents which we have just considered ? How can other things exist over and above this all-including amalgam? And if all the constituents of this amalgam are genera, how do they produce species? How does Motion produce species of Motion? Similarly with Stability and the other genera.

A word of warning must here be given against sinking the various genera in their species; and also against reducing the genus to a mere predicate, something merely seen in the species. The genus must exist at once in itself and in its species; it blends, but it must also be pure; in contributing along with other genera to form Substance, it must not destroy itself. There are problems here that demand investigation.

But since we identified the amalgam of the Existents with the particular intellect, Intellect as such being found identical with Being or Substance, and therefore prior to all the Existents, which may be regarded as its species or members, we may infer that the intellect, considered as completely unfolded, is a subsequent.

Our treatment of this problem may serve to promote our investigation; we will take it as a kind of example, and with it embark upon our enquiry.

(18) These problems at any rate all serve to show that, while in general it is necessary to look for differences by which to separate things from each other, to hunt for differences of the differences themselves is both futile and irrational. We cannot have substances of substances, quantities of quantities, qualities of qualities, differences of differences; differences must, where possible, be found outside the genus, in creative powers and the like: but where no such criteria are present, as in distinguishing dark-green from pale-green, both being regarded as derived from white and black, what expedient may be suggested?

Sense-perception and intelligence may be trusted to indicate diversity but not to explain it: explanation is outside the province of sense-perception, whose function is merely to produce a variety of information; while, as for intelligence, it works exclusively with intuitions and never resorts to explanations to justify them; there is in the movements of intelligence a diversity which separates one object from another, making further differentiation unnecessary.

Do all qualities constitute differentiae, or not? Granted that whiteness and colours in general and the qualities dependent upon touch and taste can, even while they remain species , become differentiae of other things, how can grammar and music serve as differentiae? Perhaps in the sense that minds may be distinguished as grammatical and musical, especially if the qualities are innate, in which case they do become specific differentiae.

It remains to decide whether there can be any differentia derived from the genus to which the differentiated thing belongs, or whether it must of necessity belong to another genus? The former alternative would produce differentiae of things derived from the same genus as the differentiae themselves- for example, qualities of qualities. Virtue and vice are two states differing in quality: the states are qualities, and their differentiae qualities- unless indeed it be maintained that the state undifferentiated is not a quality, that the differentia creates the quality.

But consider the sweet as beneficial, the bitter as injurious: then bitter and sweet are distinguished, not by Quality, but by Relation. We might also be disposed to identify the sweet with the thick, and the Pungent with the thin: "thick" however hardly reveals the essence but merely the cause of sweetness- an argument which applies equally to pungency.

We must therefore reflect whether it may be taken as an invariable rule that Quality is never a differentia of Quality, any more than Substance is a differentia of Substance, or Quantity of Quantity.

Surely, it may be interposed, five differs from three by two. No: it exceeds it by two; we do not say that it differs: how could it differ by a "two" in the "three"? We may add that neither can Motion differ from Motion by Motion. There is, in short, no parallel in any of the other genera.

In the case of virtue and vice, whole must be compared with whole, and the differentiation conducted on this basis. As for the differentia being derived from the same genus as themselves, namely, Quality, and from no other genus, if we proceed on the principle that virtue is bound up with pleasure, vice with lust, virtue again with the acquisition of food, vice with idle extravagance, and accept these definitions as satisfactory, then clearly we have, here too, differentiae which are not qualities.

(5) In short, whether you think that there is one genus of the Gods, one of dæmons, and in a similar manner of heroes, and souls essentially incorporeal; or whether you admit that these are severally many, you inquire what the difference of them is according to peculiarities. For if you apprehend that each of these is one [and the same genus] the whole arrangement of scientific theology is confounded. But if, as truth requires, you admit that they are genetically distinguished, and that there is not in them one common essential definition, but that those of them which are prior, are exempt from those that are inferior, it is not possible to discover their common boundaries. And even if this were possible, this very thing would destroy their peculiarities. In this way, therefore, the object of investigation cannot be found. He, however, he who directs his attention to the analogous sameness which exists in superior natures, as, for instance, in the many genera of the Gods, and again in dæmons and heroes, and, in the last place, in souls, will be able to define their peculiarities. Hence through this, it is demonstrated by us what the rectitude is of the present inquiry, and what its [accurate] distinction, and also in what manner it is impossible, and in what manner it is possible, for it to subsist.

(12) It should however be added that if the Idea of man exists in the Supreme, there must exist the Idea of reasoning man and of man with his arts and crafts; such arts as are the offspring of intellect Must be There.

It must be observed that the Ideas will be of universals; not of Socrates but of Man: though as to man we may enquire whether the individual may not also have place There. Under the heading of individuality there is to be considered the repetition of the same feature from man to man, the simian type, for example, and the aquiline: the aquiline and the simian must be taken to be differences in the Idea of Man as there are different types of the animal: but Matter also has its effect in bringing about the degree of aquilinity. Similarly with difference of complexion, determined partly by the Reason-Principle, partly by Matter and by diversity of place.

(28) We have already indicated that Activity and Passivity are to be regarded as motions, and that it is possible to distinguish absolute motions, actions, passions.

As for the remaining so-called genera, we have shown that they are reducible to those which we have posited.

With regard to the relative, we have maintained that Relation belongs to one object as compared with another, that the two objects coexist simultaneously, and that Relation is found wherever a substance is in such a condition as to produce it; not that the substance is a relative, except in so far as it constitutes part of a whole- a hand, for example, or head or cause or principle or element.

We may also adopt the ancient division of relatives into creative principles, measures, excesses and deficiencies, and those which in general separate objects on the basis of similarities and differences.

Our investigation into the kinds of Being is now complete.

(2) Our first observations must be directed to what passes in the Sensible realm for Substance. It is, we shall agree, only by analogy that the nature manifested in bodies is designated as Substance, and by no means because such terms as Substance or Being tally with the notion of bodies in flux; the proper term would be Becoming.

But Becoming is not a uniform nature; bodies comprise under the single head simples and composites, together with accidentals or consequents, these last themselves capable of separate classification.

Alternatively, Becoming may be divided into Matter and the Form imposed upon Matter. These may be regarded each as a separate genus, or else both may be brought under a single category and receive alike the name of Substance.

But what, we may ask, have Matter and Form in common? In what sense can Matter be conceived as a genus, and what will be its species? What is the differentia of Matter? In which genus, Matter or Form, are we to rank the composite of both? It may be this very composite which constitutes the Substance manifested in bodies, neither of the components by itself answering to the conception of Body: how, then, can we rank them in one and the same genus as the composite? How can the elements of a thing be brought within the same genus as the thing itself? Yet if we begin with bodies, our first-principles will be compounds.

Why not resort to analogy? Admitted that the classification of the Sensible cannot proceed along the identical lines marked out for the Intellectual: is there any reason why we should not for Intellectual-Being substitute Matter, and for Intellectual Motion substitute Sensible Form, which is in a sense the life and consummation of Matter? The inertia of Matter would correspond with Stability, while the Identity and Difference of the Intellectual would find their counterparts in the similarity and diversity which obtain in the Sensible realm.

But, in the first place, Matter does not possess or acquire Form as its life or its Act; Form enters it from without, and remains foreign to its nature. Secondly, Form in the Intellectual is an Act and a motion; in the Sensible Motion is different from Form and accidental to it: Form in relation to Matter approximates rather to Stability than to Motion; for by determining Matter's indetermination it confers upon it a sort of repose.

In the higher realm Identity and Difference presuppose a unity at once identical and different: a thing in the lower is different only by participation in Difference and in relation to some other thing; Identity and Difference are here predicated of the particular, which is not, as in that realm, a posterior.

As for Stability, how can it belong to Matter, which is distorted into every variety of mass, receiving its forms from without, and even with the aid of these forms incapable of offspring.

This mode of division must accordingly be abandoned.

(53) Hence comes discernment between things which are of like nature, not distinguished by difference of kind, character or position.

(25) There are those who lay down four categories and make a fourfold division into Substrates, Qualities, States, and Relative States, and find in these a common Something, and so include everything in one genus.

Against this theory there is much to be urged, but particularly against this posing of a common Something and a single all-embracing genus. This Something, it may be submitted, is unintelligible to themselves, is indefinable, and does not account either for bodies or for the bodiless. Moreover, no room is left for a differentia by which this Something may be distinguished. Besides, this common Something is either existent or non-existent: if existent, it must be one or other of its species;- if non-existent, the existent is classed under the non-existent. But the objections are countless; we must leave them for the present and consider the several heads of the division.

To the first genus are assigned Substrates, including Matter, to which is given a priority over the others; so that what is ranked as the first principle comes under the same head with things which must be posterior to it since it is their principle.

First, then: the prior is made homogeneous with the subsequent. Now this is impossible: in this relation the subsequent owes its existence to the prior, whereas among things belonging to one same genus each must have, essentially, the equality implied by the genus; for the very meaning of genus is to be predicated of the species in respect of their essential character. And that Matter is the basic source of all the rest of things, this school, we may suppose, would hardly deny.

Secondly: since they treat the Substrate as one thing, they do not enumerate the Existents; they look instead for principles of the Existents. There is however a difference between speaking of the actual Existents and of their principles.

If Matter is taken to be the only Existent, and all other things as modifications of Matter, it is not legitimate to set up a single genus to embrace both the Existent and the other things; consistency requires that Being be distinguished from its modifications and that these modifications be duly classified.

Even the distinction which this theory makes between Substrates and the rest of things is questionable. The Substrate is one thing and admits of no differentia- except perhaps in so far as it is split up like one mass into its various parts; and yet not even so, since the notion of Being implies continuity: it would be better, therefore, to speak of the Substrate, in the singular.

(454) I said: Suppose that by way of illustration we were to ask the question whether there is not an opposition in nature between bald men and hairy men; and if this is admitted by us, then, if bald men are cobblers, we should forbid the hairy men to be cobblers, and conversely? That would be a jest, he said. Yes, I said, a jest; and why? because we never meant when we constructed the State, that the opposition of natures should extend to every difference, but only to those differences which affected the pursuit in which the individual is engaged; we should have argued, for example, that a physician and one who is in mind a physician 5 may be said to have the same nature. True. Whereas the physician and the carpenter have different natures? Certainly. And if, I said, the male and female sex appear to differ in their fitness for any art or pursuit, we should say that such pursuit or art ought to be assigned to one or the other of them; but if the difference consists only in women bearing and men begetting children, this does not amount to a proof that a woman differs from a man in respect of the sort of education she should receive; and we shall therefore continue to maintain that our guardians and their wives ought to have the same pursuits. Very true, he said. Next, we shall ask our opponent how, in reference to any

(12) If then we do not propose to divide Quality in this manner, what basis of division have we?

We must examine whether qualities may not prove to be divisible on the principle that some belong to the body and others to the soul. Those of the body would be subdivided according to the senses, some being attributed to sight, others to hearing and taste, others to smell and touch. Those of the soul would presumably be allotted to appetite, emotion, reason; though, again, they may be distinguished by the differences of the activities they condition, in so far as activities are engendered by these qualities; or according as they are beneficial or injurious, the benefits and injuries being duly classified. This last is applicable also to the classification of bodily qualities, which also produce differences of benefit and injury: these differences must be regarded as distinctively qualitative; for either the benefit and injury are held to be derived from Quality and the quale, or else some other explanation must be found for them.

A point for consideration is how the quale, as conditioned by Quality, can belong to the same category: obviously there can be no single genus embracing both.

Further, if "boxer" is in the category of Quality, why not "agent" as well? And with agent goes "active." Thus "active" need not go into the category of Relation; nor again need "passive," if "patient" is a quale. Moreover, agent" is perhaps better assigned to the category of Quality for the reason that the term implies power, and power is Quality. But if power as such were determined by Substance , the agent, though ceasing to be a quale, would not necessarily become a relative. Besides, "active" is not like "greater": the greater, to be the greater, demands a less, whereas "active" stands complete by the mere possession of its specific character.

It may however be urged that while the possession of that character makes it a quale, it is a relative in so far as it directs upon an external object the power indicated by its name. Why, then, is not "boxer" a relative, and "boxing" as well? Boxing is entirely related to an external object; its whole theory pre-supposes this external. And in the case of the other arts- or most of them- investigation would probably warrant the assertion that in so far as they affect the soul they are qualities, while in so far as they look outward they are active and as being directed to an external object are relatives. They are relatives in the other sense also that they are thought of as habits.

Can it then be held that there is any distinct reality implied in activity, seeing that the active is something distinct only according as it is a quale? It may perhaps be held that the tendency towards action of living beings, and especially of those having freewill, implies a reality of activity .

But what is the function of the active in connection with those non-living powers which we have classed as qualities? Doubtless to recruit any object it encounters, making the object a participant in its content.

But if one same object both acts and is acted upon, how do we then explain the active? Observe also that the greater- in itself perhaps a fixed three yards' length- will present itself as both greater and less according to its external contacts.

It will be objected that greater and less are due to participation in greatness and smallness; and it might be inferred that a thing is active or passive by participation in activity or passivity.

This is the place for enquiring also whether the qualities of the Sensible and Intellectual realms can be included under one head- a question intended only for those who ascribe qualities to the higher realm as well as the lower. And even if Ideal Forms of qualities are not posited, yet once the term "habit" is used in reference to Intellect, the question arises whether there is anything common to that habit and the habit we know in the lower.

Wisdom too is generally admitted to exist There. Obviously, if it shares only its name with our wisdom, it is not to be reckoned among things of this sphere; if, however, the import is in both cases the same, then Quality is common to both realms- unless, of course, it be maintained that everything There, including even intellection, is Substance.

This question, however, applies to all the categories: are the two spheres irreconcilable, or can they be co-ordinated with a unity?

(1) And all dependent from Above are subdivided into species in the fashion which I am to tell. The genera of all things company with their own species; so that the genus is a class in its entirety, the species is part of a genus. The genus of the Gods will, therefore, make the species of the Gods out of itself. In like way, too, the genus of the daimons, and of men, likewise of birds, and of all [animals] the Cosmos doth contain within itself, brings into being species like itself. There is besides a genus other than the animal,—a genus, or indeed a soul, in that it’s not without sensation,—in consequence of which it both finds happiness in suitable conditions, and pines and spoils in adverse ones;—I mean [the class] of all things on the earth which owe their life to the sound state of roots and shoots, of which the various kinds are scattered through the length and breadth of Earth.

(10) Another method of division is possible: substances may be classed as hot-dry, dry-cold, cold-moist, or however we choose to make the coupling. We may then proceed to the combination and blending of these couples, either halting at that point and going no further than the compound, or else subdividing by habitation- on the earth, in the earth- or by form and by the differences exhibited by living beings, not qua living, but in their bodies viewed as instruments of life.

Differentiation by form or shape is no more out of place than a division based on qualities- heat, cold and the like. If it be objected that qualities go to make bodies what they are, then, we reply, so do blendings, colours, shapes. Since our discussion is concerned with Sensible Substance, it is not strange that it should turn upon distinctions related to sense-perception: this Substance is not Being pure and simple, but the Sensible Being which we call the Universe.

We have remarked that its apparent subsistence is in fact an assemblage of Sensibles, their existence guaranteed to us by sense-perception. But since their combination is unlimited, our division must be guided by the Form-Ideas of living beings, as for example the Form-Idea of Man implanted in Body; the particular Form acts as a qualification of Body, but there is nothing unreasonable in using qualities as a basis of division.

We may be told that we have distinguished between simple and composite bodies, even ranking them as opposites. But our distinction, we reply, was between material and organic bodies and raised no question of the composite. In fact, there exists no means of opposing the composite to the simple; it is necessary to determine the simples in the first stage of division, and then, combining them on the basis of a distinct underlying principle, to differentiate the composites in virtue of their places and shapes, distinguishing for example the heavenly from the earthly.

These observations will suffice for the Being , or rather the Becoming, which obtains in the Sensible realm.

(2) Now the reasoning faculty which undertakes this problem is not a unity but a thing of parts; it brings the bodily nature into the enquiry, borrowing its principles from the corporeal: thus it thinks of the Essential Existence as corporeal and as a thing of parts; it baulks at the unity because it does not start from the appropriate principles. We, however, must be careful to bring the appropriately convincing principles to the discussion of the Unity, of perfect Being: we must hold to the Intellectual principles which alone apply to the Intellectual Order and to Real Being.

On the one hand there is the unstable, exposed to all sorts of change, distributed in place, not so much Being as Becoming: on the other, there is that which exists eternally, not divided, subject to no change of state, neither coming into being nor falling from it, set in no region or place or support, emerging from nowhere, entering into nothing, fast within itself.

In dealing with that lower order we would reason from its own nature and the characteristics it exhibits; thus, on a plausible foundation, we achieve plausible results by a plausible system of deduction: similarly, in dealing with the Intellectual, the only way is to grasp the nature of the essence concerned and so lay the sure foundations of the argument, not forgetfully straying over into that other order but basing our treatment on what is essential to the Nature with which we deal.

In every entity the essential nature is the governing principle and, as we are told, a sound definition brings to light many even of the concomitants: where the essential nature is the entire being, we must be all the more careful to keep to that, to look to that, to refer all to that.

(2) But, as your question now stands, with respect to the peculiarities by which these genera are separated, you alone speak of the peculiarities of energies. Hence you inquire concerning the difference in the last things pertaining to them; but you leave uninvestigated such things as are first, and most honourable in them, and which are the elements of their difference. In the same place, also, something is added concerning “ efficacious and passive motions ,” which is a division by no means adapted to the difference of the more excellent genera. For the contrariety of action and passion is not inherent in any one of them; but their energies are unrestrained, immutable, and without habitude to their opposites. Hence, neither must we admit in them motions of such a kind as arise from action and passion. For neither do we admit in the soul a self-motion, which consists of the mover and that which is moved; but we conceive that it is a certain simple essential motion, subsisting from itself, and not possessing a habitude to another thing, and exempt from acting on, and suffering from, itself. Who, therefore, can endure that the peculiarities of the genera superior to the soul, should be distinguished according to active or passive motions?

(3) For that, in order that a man should be complete in either part, observe that he hath been composed of elements of either part in sets of four;—with hands, and feet, both of them pairs, and with the other members of his body, by means of which he may do service to the lower (that is to say the terrene) world. And to these parts [are added other] four;—of sense, and soul, of memory, and foresight, by means of which he may become acquainted with the rest of things divine, and judge of them. Hence it is brought about that man investigates the differences and qualities, effects and quantities of things, with critical research; yet, as he is held back with the too heavy weight of body’s imperfection, he cannot properly descry the causes of the nature of [all] things which [really] are the true ones.

(2) The species however, and the parts of it, may be surveyed as follows: Since there are two parts of the soul, the rational and the irrational; the latter is divided into the irascible and appetitive. And the rational part, indeed, is that by which we judge and contemplate; but the irrational part is that by which we are impelled and desire. And of this, that which is as it were adapted to defend us, and revenge incidental molestations, is denominated the irascible part; but that which is as it were orectic of, and desires to preserve the proper constitution of the body, is the appetitive part. It is evident therefore, that the multitude of the virtues, their differences, and their peculiarities, follow conformably to these parts of the soul.

(1) But neither must we admit that cause of the distinction of these genera which you subjoin, viz. “ that it is an arrangement with reference to different bodies; as, for instance, of Gods to etherial bodies, but of dæmons to aerial bodies, and of souls to such as are terrene .” For such an arrangement as this, which resembles that of Socrates to a tribe, when he is a senator, is unworthy of the divine genera, because all of them are essentially unrestrained and free. To which may be added, that it is dreadfully absurd to ascribe to bodies a principal power of giving a specific distinction to the first causes of themselves. For bodies are in servile subjection to these causes, and are ministrant to generation. And farther still, the genera of the more excellent natures are not in bodies, but the former externally rule over the latter. Hence they are not changed in conjunction with bodies. Again, they impart from themselves to bodies every such good as they are able to receive, but they themselves receive nothing from bodies; so that neither will they derive from them certain peculiarities.