(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.

(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.

(3) We assert, then, a plurality of Existents, but a plurality not fortuitous and therefore a plurality deriving from a unity.

But even admitting this derivation from a unity- a unity however not predicated of them in respect of their essential being- there is, surely, no reason why each of these Existents, distinct in character from every other, should not in itself stand as a separate genus.

Is, then, this unity external to the genera thus produced, this unity which is their source though it cannot be predicated of them in respect of their essence? it is indeed external; the One is beyond; it cannot, therefore, be included among the geneANSWER: it is the source, while they stand side by side as genera. Yet surely the one must somehow be included ? No: it is the Existents we are investigating, not that which is beyond Existence.

We pass on, then, to consider that which is included, and find to our surprise the cause included with the things it causes: it is surely strange that causes and effects should be brought into the same genus.

But if the cause is included with its effects only in the sense in which a genus is included with its subordinates, the subordinates being of a different order, so that it cannot be predicated of them whether as their genus or in any other relation, these subordinates are obviously themselves genera with subordinates of their own: you may, for example, be the cause of the operation of walking, but the walking is not subordinate to you in the relation of species to genus; and if walking had nothing prior to it as its genus, but had posteriors, then it would be a genus and rank among the Existents.

Perhaps, however, it must be utterly denied that unity is even the cause of other things; they should be considered rather as its parts or elements- if the terms may be allowed,- their totality constituting a single entity which our thinking divides. All unity though it be, it goes by a wonderful power out into everything; it appears as many and becomes many when there is a motion; the fecundity of its nature causes the One to be no longer one, and we, displaying what we call its parts, consider them each as a unity and make them into "genera," unaware of our failure to see the whole at once. We display it, then, in parts, though, unable to restrain their natural tendency to coalesce, we bring these parts together again, resign them to the whole and allow them to become a unity, or rather to be a unity.

All this will become clearer in the light of further consideration- when, that is to say, we have ascertained the number of the genera; for thus we shall also discover their causes. It is not enough to deny; we must advance by dint of thought and comprehension. The way is clear:

(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.

(1) And yet the species of all genera are interblended with all genera; some which have previously been made, some which are made from these. The latter, then, which are being made,—either by Gods, or daimons, or by men,—are species all most closely like to their own several genera. For that it is impossible that bodies should be formed without the will of God; or species be configured without the help of daimons; or animals be taught and trained without the help of men.

(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.

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

(19) Are we to think of the indivisible phase of the soul and the divided as making one thing in a coalescence; or is the indivisible in a place of its own and under conditions of its own, the divisible being a sequent upon it, a separate part of it, as distinct as the reasoning phase is from the unreasoning?

The answer to this question will emerge when we make plain the nature and function to be attributed to each.

The indivisible phase is mentioned without further qualification; but not so the divisible; "that soul" we read "which becomes divisible in bodies"- and even this last is presented as becoming partible, not as being so once for all.

"In bodies": we must then, satisfy ourselves as to what form of soul is required to produce life in the corporeal, and what there must be of soul present throughout such a body, such a completed organism.

Now, every sensitive power- by the fact of being sensitive throughout- tends to become a thing of parts: present at every distinct point of sensitiveness, it may be thought of as divided. In the sense, however, that it is present as a whole at every such point, it cannot be said to be wholly divided; it "becomes divisible in body." We may be told that no such partition is implied in any sensations but those of touch; but this is not so; where the participant is body that divisibility in the sensitive agent will be a condition of all other sensations, though in less degree than in the case of touch. Similarly the vegetative function in the soul, with that of growth, indicates divisibility; and, admitting such locations as that of desire at the liver and emotional activity at the heart, we have the same result. It is to be noted, however, as regards these sensations, that the body may possibly not experience them as a fact of the conjoint thing but in another mode, as rising within some one of the elements of which it has been participant : reasoning and the act of the intellect, for instance, are not vested in the body; their task is not accomplished by means of the body which in fact is detrimental to any thinking on which it is allowed to intrude.

Thus the indivisible phase of the soul stands distinct from the divisible; they do not form a unity, but, on the contrary, a whole consisting of parts, each part a self-standing thing having its own peculiar virtue. None the less, if that phase which becomes divisible in body holds indivisibility by communication from the superior power, then this one same thing may be at once indivisible and divisible; it will be, as it were, a blend, a thing made up of its own divisible self with, in addition, the quality that it derives from above itself.

(9) So much for one of the genera- the "Substance," so called, of the Sensible realm.

But what are we to posit as its species? how divide this genus?

The genus as a whole must be identified with body. Bodies may be divided into the characteristically material and the organic: the material bodies comprise fire, earth, water, air; the organic the bodies of plants and animals, these in turn admitting of formal differentiation.

The next step is to find the species of earth and of the other elements, and in the case of organic bodies to distinguish plants according to their forms, and the bodies of animals either by their habitations- on the earth, in the earth, and similarly for the other elements- or else as light, heavy and intermediate. Some bodies, we shall observe, stand in the middle of the universe, others circumscribe it from above, others occupy the middle sphere: in each case we shall find bodies different in shape, so that the bodies of the living beings of the heavens may be differentiated from those of the other elements.

Once we have classified bodies into the four species, we are ready to combine them on a different principle, at the same time intermingling their differences of place, form and constitution; the resultant combinations will be known as fiery or earthy on the basis of the excess or predominance of some one element.

The distinction between First and Second Substances, between Fire and a given example of fire, entails a difference of a peculiar kind- the difference between universal and particular. This however is not a difference characteristic of Substance; there is also in Quality the distinction between whiteness and the white object, between grammar and some particular grammar.

The question may here be asked: "What deficiency has grammar compared with a particular grammar, and science as a whole in comparison with a science?" Grammar is certainly not posterior to the particular grammar: on the contrary, the grammar as in you depends upon the prior existence of grammar as such: the grammar as in you becomes a particular by the fact of being in you; it is otherwise identical with grammar the universal.

Turn to the case of Socrates: it is not Socrates who bestows manhood upon what previously was not Man, but Man upon Socrates; the individual man exists by participation in the universal.

Besides, Socrates is merely a particular instance of Man; this particularity can have no effect whatever in adding to his essential manhood.

We may be told that Man is Form alone, Socrates Form in Matter. But on this very ground Socrates will be less fully Man than the universal; for the Reason-Principle will be less effectual in Matter. If, on the contrary, Man is not determined by Form alone, but presupposes Matter, what deficiency has Man in comparison with the material manifestation of Man, or the Reason-Principle in isolation as compared with its embodiment in a unit of Matter?

Besides, the more general is by nature prior; hence, the Form-Idea is prior to the individual: but what is prior by nature is prior unconditionally. How then can the Form take a lower rank? The individual, it is true, is prior in the sense of being more readily accessible to our cognisance; this fact, however, entails no objective difference.

Moreover, such a difference, if established, would be incompatible with a single Reason-Principle of Substance; First and Second Substance could not have the same Principle, nor be brought under a single genus.

(1) According to another division, therefore, the numerous herd [or the great mass] of men is arranged under nature, is governed by physical powers, looks downward to the works of nature, gives completion to the administration of Fate, and to things pertaining to Fate, because it belongs to the order of it, and always employs practical reasoning about such particulars alone as subsist according to nature. But there are a certain few who, by employing a certain supernatural power of intellect, are removed indeed from nature, but are conducted to a separate and unmingled intellect; and these, at the same time, become superior to physical powers. Others again, who are the media between these, tend to things which subsist between nature and a pure intellect. And of these, some indeed equally follow both nature and an immaculate intellect; others embrace a life which is mingled from both; and others are liberated from things subordinate, and betake themselves to such as are more excellent.

(2) This division, therefore, being made, that which follows will most manifestly take place. For those who are governed by the nature of the universe, who lived conformably to this, and employ the powers of nature, these should embrace a mode of worship adapted to nature, and to the bodies that are moved by nature, and should choose for this purpose appropriate places, air, matter, the powers of matter, bodies, and the habits of bodies, qualities, and proper motions, the mutations of things in generation, and other things connected with these, both in other parts of piety and in that part of it which pertains to sacrifice. But those who live conformably to intellect alone, and to the life of intellect, and are liberated from the bonds of nature, these should exercise in all the parts of theurgy the intellectual and incorporeal mode of worship. And those who are the media between these, should labour differently in the paths of piety, conformably to the differences of this middle condition of life, either by embracing both modes of piety, or separating themselves from one of the modes [and adhering to the other], or receiving both these modes as the foundation of things of a more honourable nature. For without these they never can arrive at things supereminent. Or, in some other way, they should thus, in a becoming manner, labour in the paths of sanctity.

(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?

(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.

(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.

(3) These divisions are more or less artificial and arbitrary, for the truth is that all of the three divisions are but ascending degrees of the great scale of Life, the lowest point of which is undifferentiated Matter, and the highest point that of Spirit. And, moreover, the different Planes shade into each other, so that no hard and fast division may be made between the higher phenomena of the Physical and the lower of the Mental; or between the higher of the Mental and the lower of the Physical.

(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.

(11) We are bound however to enquire under what mode unity is contained in Being. How is what is termed the "dividing" effected- especially the dividing of the genera Being and unity? Is it the same division, or is it different in the two cases?

First then: In what sense, precisely, is any given particular called and known to be a unity? Secondly: Does unity as used of Being carry the same connotation as in reference to the Absolute?

Unity is not identical in all things; it has a different significance according as it is applied to the Sensible and the Intellectual realms- Being too, of course, comports such a difference- and there is a difference in the unity affirmed among sensible things as compared with each other; the unity is not the same in the cases of chorus, camp, ship, house; there is a difference again as between such discrete things and the continuous. Nevertheless, all are representations of the one exemplar, some quite remote, others more effective: the truer likeness is in the Intellectual; Soul is a unity, and still more is Intellect a unity and Being a unity.

When we predicate Being of a particular, do we thereby predicate of it unity, and does the degree of its unity tally with that of its being? Such correspondence is accidental: unity is not proportionate to Being; less unity need not mean less Being. An army or a choir has no less Being than a house, though less unity.

It would appear, then, that the unity of a particular is related not so much to Being as to a standard of perfection: in so far as the particular attains perfection, so far it is a unity; and the degree of unity depends on this attainment. The particular aspires not simply to Being, but to Being-in-perfection: it is in this strain towards their perfection that such beings as do not possess unity strive their utmost to achieve it.

Things of nature tend by their very nature to coalesce with each other and also to unify each within itself; their movement is not away from but towards each other and inwards upon themselves. Souls, moreover, seem to desire always to pass into a unity over and above the unity of their own substance. Unity in fact confronts them on two sides: their origin and their goal alike are unity; from unity they have arisen, and towards unity they strive. Unity is thus identical with Goodness ; for no being ever came into existence without possessing, from that very moment, an irresistible tendency towards unity.

From natural things we turn to the artificial. Every art in all its operation aims at whatsoever unity its capacity and its models permit, though Being most achieves unity since it is closer at the start.

That is why in speaking of other entities we assert the name only, for example man; when we say "one man," we have in mind more than one; and if we affirm unity of him in any other connection, we regard it as supplementary : but when we speak of Being as a whole we say it is one Being without presuming that it is anything but a unity; we thereby show its close association with Goodness.

Thus for Being, as for the others, unity turns out to be, in some sense, Principle and Term, not however in the same sense as for things of the physical order- a discrepancy leading us to infer that even in unity there are degrees of priority.

How, then, do we characterize the unity in Being? Are we to think of it as a common property seen alike in all its parts? In the first place, the point is common to lines and yet is not their genus, and this unity we are considering may also be common to numbers and not be their genus- though, we need hardly say, the unity of Unity-Absolute is not that of the numbers, one, two and the rest. Secondly, in Being there is nothing to prevent the existence of prior and posterior, simple and composite: but unity, even if it be identical in all the manifestations of Being, having no differentiae can produce no species; but producing no species it cannot be a genus.

(1) We have examined the proposed "ten genera": we have discussed also the theory which gathers the total of things into one genus and to this subordinates what may be thought of as its four species. The next step is, naturally, to expound our own views and to try to show the agreement of our conclusions with those of Plato.

Now if we were obliged to consider Being as a unity, the following questions would be unnecessary:

Is there one genus embracing everything, or are there genera which cannot be subsumed under such a unity? Are there first-principles? Are first-principles to be identified with genera, or genera with first-principles? Or is it perhaps rather the case that while not all genera are first-principles, all first-principles are at the same time genera? Or is the converse true? Or again, do both classes overlap, some principles being also genera, and some genera also principles? And do both the sets of categories we have been examining imply that only some principles are genera and some genera principles? or does one of them presuppose that all that belongs to the class of genera belongs also to the class of principles?

Since, however, we affirm that Being is not a unity- the reason for this affirmation is stated by Plato and others- these questions become imperative, once we are satisfied as to the number of genera to be posited and the grounds for our choice.

The subject of our enquiry, then, is the Existent or Existents, and it presents immediately two problems demanding separate analysis:

What do we mean by the Existent? This is naturally the first question to be examined.

What is that which, often taken for Being , is in our view Becoming and never really Being? Note however that these concepts are not to be taken as distinguished from each other in the sense of belonging to a genus, Something, divided into Being and Becoming; and we must not suppose that Plato took this view. It would be absurd to assign Being to the same genus as non-Being: this would be to make one genus of Socrates and his portrait. The division here means a definite marking-off, a setting asunder, leading to the assertion that what takes the appearance of Being is not Being and implying that the nature of True Being has been quite misapprehended. Being, we are taught, must have the attribute of eternity, must be so constituted as never to belie its own nature.

This, then, is the Being of which we shall treat, and in our investigation we shall assume that it is not a unity: subsequently we ask leave to say something on the nature of Becoming and on what it is that comes to be, that is, on the nature of the world of Sense.

(1) After the body of the universe, also, many things are generated by the nature of it. For the concord of similars, and the contrariety of dissimilars, effect not a few things. Farther still, the assemblage of many things into the one animal of the universe, and the powers in the world, whatever the number and quality of them may be, effect, in short, one thing in wholes and another in parts, on account of the divided imbecility of parts. Thus, for instance, the friendship, love, and contention which subsist in energy in the universe, become passions in the partial natures by which they are participated. Those things, likewise, that are preestablished in forms and pure reasons in the nature of wholes, participate of a certain material indigence, and privation of morphe , in things which subsist according to a part. And things which are conjoined to each other in wholes are separated in parts. Hence partible natures, which participate of wholes in conjunction with matter, degenerate from them in all things, and also from what is beautiful and perfect. But some parts are corrupted, in order that wholes may be preserved in a condition conformable to nature. Sometimes, likewise, parts are compressed and weighed down, though at the same time wholes remain impassive to a molestation of this kind.

(2) But are we really obliged to posit the existence of such genera?

Take Substance, for Substance must certainly be our starting-point: what are the grounds for regarding Substance as one single genus?

It has been remarked that Substance cannot be a single entity common to both the Intellectual and the Sensible worlds. We may add that such community would entail the existence of something prior to Intellectual and Sensible Substances alike, something distinct from both as predicated of both; and this prior would be neither body nor unembodied; for it were one or the other, body would be unembodied, or the unembodied would be the body.

This conclusion must not however prevent our seeking in the actual substance of the Sensible world an element held in common by Matter, by Form and by their Composite, all of which are designated as substances, though it is not maintained that they are Substance in an equal degree; Form is usually held to be Substance in a higher degree than Matter, and rightly so, in spite of those who would have Matter to be the more truly real.

There is further the distinction drawn between what are known as First and Second Substances. But what is their common basis, seeing that the First are the source from which the Second derive their right to be called substances?

But, in sum, it is impossible to define Substance: determine its property, and still you have not attained to its essence. Even the definition, "That which, numerically one and the same, is receptive of contraries," will hardly be applicable to all substances alike.