«Porphyry, as Boethius points out [in his Commentary on the Isagoge], raises three profitable questions whose answers are shrouded in mystery and though not a few philosophers have attempted to solve them, few have succeeded in doing so. The first is: Do genera and species really exist or are they simply something in the mind? It is as if [Porphyry] were asking whether their existence is a fact or merely a matter of opinion. The second is: Granting they do exist, are they corporeal or incorporeal? The third is: Do they exist apart from sensible things or only in them? For there are two types of incorporeal things. Some, like God or the soul, can subsist in their incorporeality apart from anything sensible. Others are unable to exist apart from the sensible objects in which they are found. A line, for example, is unable to exist apart from some bodily subject simply thought; or if they do exist whether they are corporeal incorporeal, or whether, on the admission they are incorporeal, they are separated from sensibles or exist only in and dependent upon sensible things, and other things of this sort.”
“Other things of this sort” can be interpreted in various ways. We could take him to mean: “I refuse to discuss these three questions and other related matters.” For other relevant questions could be raised that pose similar problems. For instance, what is the common basis or reason for applying universal names to things; which boils down to explaining to what extent different things agree; or how should one understand those universal names wherein one seems to conceive of nothing, where the universal term in a word seems to have no referent? And there are many other difficult points. By understanding “other things of this sort” in this way, we can add a fourth question: Do genera and species, as long as they remain such, require that the subject they name have some reality or, if all the things they designate were destroyed, could the universal consist simply in its significance for the mind, as would be the case with the name “rose” when no roses are in bloom which it could designate in general? . . .
Since genera and species are obviously instances of universals and in mentioning them Porphyry touches on the nature of universals in general, we may distinguish the properties common to universals by studying them in these samples. Let us inquire then whether they apply only to words or to things as well.
Aristotle defines the universal as “that which is of such a nature as to be predicated of many.” Porphyry, on the other hand, goes on to define the singular or individual as “that which is predicated of a single individual.”
Authorities then seem to apply “universal” to things as much as they do to words. Aristotle himself does this, declaring by way of preface to his definition of the universal, that “some things are universal, others individual. Now by ‘universal’ I mean that which is of such a nature as to be predicated of many, whereas ‘individual’ is not something of this kind.” Porphyry too, having stated that the species is composed of a genus and difference, proceeds to locate it in the nature of things. From this it is clear that things themselves fall under a universal noun.
Nouns too are called universals. That is why Aristotle says: “The genus specifies the quality with reference to substance, for it signifies what sort of thing it is.”
“It seems then that things as well as words are called universals.” . . .
However, things taken either singly or collectively cannot be called universals, because they are not predicable of many. Consequently it remains to ascribe this form of universality to words alone. Just as grammarians call certain nouns proper and others appellative, so dialecticians call certain simple words particulars, that is, individuals, and others universals. A universal word is one which is able to be predicated of many by reason of its intention, such as the noun “man,” which can be joined with the names of particular men by reason of the nature of the subject on which they are imposed A particular word, however, is one which is predicable only of a single subject as Socrates when it is taken as the name of but one individual. For if you take it equivocally, you give it the signification not of one word but of many. For according to Priscian, many nouns can obviously be brought together in a single word. When a universal then is described as “that which is predicable of many,” that which indicates not only the simplicity of the word as a discrete expression, but also the unity of signification lacking in an equivocal term….
Now that we have defined “universal” and “particular” in regard to words, let us investigate in particular the properties of those which are universal. For questions have been raised about universals, since serious doubts existed as to their meaning because there seemed to be no subject to which they referred. Neither did they express the sense of any one thing. These universal terms then appeared to be imposed on nothing, since it is clear that all things subsisting in themselves are individuals and, as has been shown, they do not share in some one thing by virtue of which a universal name could be given to them. Since it is certain then that (a) universals are not imposed on things by reason of their individual differences, for then they would not be common but singular, (b) nor can they designate things which share in some identical entity, for it is not a thing in which they agree, there seems to be nothing from which universals might derive their meaning, particularly since their sense is not restricted to any one thing…. Since “man” is imposed on individuals for an identical reason, viz. because each is a rational, mortal animal, the very generality of the designation prevents one from understanding the term of just one man in the way, for example, that one understands by Socrates just one unique person, which is why it is called a particular. But the common term “man” does not mean just Socrates, or any other man. Neither does it designate a collection, nor does it, as some think, mean just Socrates insofar as he is man. For even if Socrates alone were sitting in this house and because of that the proposition “A man sits in this house” is true, still by the name “man,” there is no way of getting to Socrates except insofar as he too is a man. Otherwise, from the proposition itself, “sitting” would be understood to inhere in Socrates, so that from “A man sits in this house,” one could infer “Socrates sits in this house.” And the same applies to any other individual man. Neither can “A man sits in this house” be understood of a collection, since the proposition can be true if only one man is there. Consequently, there is not a single thing that “man” or any other universal term seems to signify, since there is not a single thing whose sense the term seems to express. Neither does it seem there could be any sense if no subject is thought of. Universals then appear to be totally devoid of meaning.
And yet this is not the case. For universals do signify distinct individuals to the extent of giving names to them, but this significative function does not require that one grasps a sense which arises out of them and which belongs to each of them. “Man,” for example, does name individual things, but for the common reason that they are all men. That is why it is called a universal. Also there is a certain sense common, not proper that is applicable to those – individuals which one conceives to be alike.
But let us look carefully now into some matters we have touched on only briefly, viz. (a) what is the common reason for imposing a universal name on things, (b) what is this intellectual conception of a common likeness, and (c) is a word said to be common because of some common cause by virtue of which all the things it designates are alike, or is it merely because we have a common concept for all of them, or is it for both of these reasons?
Let us consider first the question of the common cause. As we noted earlier, each individual man is a discrete subject since he has as proper to himself not only an essence but also whatever forms [or qualifications] that essence may have. Nevertheless, they agree in this that they are all men. Since there is no man who is not a discrete or distinct individual thing, I do not say they agree “in man,” but “in being a man.” Now if you consider the matter carefully, man or any other thing is not the same as “to be a man,” even as “not to be in a subject” is not a thing, nor is there anything which is “not to undergo contrariety” or “not to be subject to greater or lesser degrees,” and still Aristotle says these are points in which all substances agree. Since there is no thing in which things could possibly agree, if there is any agreement among certain things, this must not be taken to be some thing. Just as Socrates and Plato are alike in being men, so a horse and donkey are alike in not being men. It is for this reason that they are called “nonmen.” Different individuals then agree either in being the same or in not being the same, e.g. in being men or white, or in not being men or being white.
Still this agreement among things (which itself is not a thing) must not be regarded as a case of bringing together things which are real on the basis of nothing. In point of fact we do speak of this agreeing with that to the extent of their having the same status, that of man, i.e. the two agree in that they are men. But what we perceive is merely that they are men, and there is not the slightest difference between them, I say, in their being men, even though we may not call this an essence. But “being a man” (which is not a thing) we do call “the status of man” and we have also called it “the common cause for imposing on individuals a universal name.” For we frequently give the name “cause” to some characteristic that is not itself a thing as when one says “He was beaten because he did not wish to appear in court.” His not wishing to appear in court, cited here as a cause is not a [constitutive] essence [of his being beaten].
We can also designate as “the status of man” those things themselves in a man’s nature which the one who imposed the word conceives according to a common likeness.
Having shown how universals signify, namely by functioning as names of things, and having presented what the reason for imposing such general names is, let us indicate just what these universal meanings consist of.
To begin with, let us point out the distinguishing features of all intellectual conception or understanding. Though sense perception as well as intellectual conception are both functions of the soul, there is a difference between the two. Bodies and what inhere in them are objects of sensory knowledge, e.g. a tower or its sensory qualities. In the exercise of this function, however, the soul makes use of corporeal instruments. In understanding or conceiving something intellectually, the soul needs no corporeal organ and consequently no bodily subject in which the thought object inheres is required. It is enough that the mind constructs for itself a likeness of these things and the action called intellection is concerned with this [cognitive content]. Hence, if the tower is removed or destroyed, the sense perception that dealt with it perishes, but the intellectual conception of the tower remains in the likeness preserved in the mind. As the act of sense perception is not the sensed thing itself, so the act of the intellect is not itself the form understood or conceived intellectually. Understanding is an activity of the soul by virtue of which it is said to understand, but the form toward which understanding is directed is a kind of image or construct which the mind fashions for itself at will, like those imaginary cities seen in dreams or the form of a projected building which the architect conceives after the manner of a blueprint. This construct is not something one can call either substance or accident.
Nevertheless, there are those who simply identify it with the act itself through which it is understood or conceived. Thus they speak of the tower building itself, which I think of when the tower is not there and which I conceive to be lofty, square, and situated in a spacious plain, as being the same as thinking of a tower. But we prefer to call the [conceptual] image as such the likeness of the thing.
There is of course nothing to prevent the act of understanding itself from being called in some sense a “likeness” because it obviously conceives what is, properly speaking, a likeness of the thing. Still, as we have said and rightly so the two are not the same. For, I ask: “Does the squareness or loftiness represent the actual form or quality possessed by the act of understanding itself when one thinks of the height and the way the tower is put together?” Surely the actual squareness and height are present only in bodies and from an imagined quality no act of understanding or any other real essence can be constructed. What remains then but that the substance, like the quality of which it is the subject, is also fictive? Perhaps one could also say that a mirror or reflected image is not itself a true “thing,” since there often appears on the whitish surface of the mirror a color of contrary quality….
Having treated in general the nature of understanding, let us consider how a universal and a particular conception differ. The conception associated with a universal name is an image that is general and indiscriminate, whereas the image associated with a singular word represents the proper and characteristic form, as it were, of a single thing, i.e. it applies to one and only one person. When I hear the word “man,” for instance, a certain likeness arises in my mind which is so related to individual men that it is proper to none but common to all. But when I hear “Socrates,” a certain form arises in my mind which is the likeness of a particular person…. Hence it is correct to say “man” does not rightly signify Socrates or any other man, since by virtue of this name no one in particular is identified; yet it is a name of particular things. “Socrates,” on the other hand, must not only name a particular thing, but it must also determine just what thing is its subject…. To show what pertains to the nature of all lions, a picture can be constructed which represents nothing that is the peculiar property of only one of them. On the other hand, a picture suited to distinguish any one of them can be drawn by depicting something proper to the one in question, for example, by painting it as limping, maimed, or wounded by the spear of Hercules. Just as one can paint one figure that is general and another that is particular, so too can one form one conception of things that is common and another conception that is proper.
There is some question, however, and not without reason, whether or not this [universal] name also signifies this conceptual form to which the understanding is directed. Both authority and reason, however, seem to be unanimous in affirming that it does.
For Priscian, after first showing how universals were applied commonly to individuals, seemed to introduce another meaning they had, namely the common form. He states that “the general and special forms of things which were given intelligibility in the divine mind before being produced in bodies could be used to reveal what the natural genera and species of things are.” In this passage he views God after the fashion of an artist who first conceives in his mind a [model or] exemplar form of what he is to fashion and who works according to the likeness of this form, which form is said to be embodied when a real thing is constructed in its likeness.
It may be all right to ascribe such a common conception to God, but not to man. For those works of God like a man, a soul, or a stone represent general or special states of nature, whereas those of a human artisan like a house or a sword do not. For “house” and “sword” do not pertain to nature as the other terms do. They are the names not of a substance but of something accidental and therefore they are neither genera not ultimate species. Conceptions by abstraction [of the true nature of things] may well be ascribed to the divine mind but may not be ascribed to that of man, because men, who know things only through the medium of their senses, scarcely ever arrive at such an ideal understanding and never conceive the [underlying] natures of things in their purity. But God knew all things he created for what they were and this even before they actually existed. He can discriminate between these individual states as they are in themselves; senses are no hindrance to him who alone has true understanding of things. Of those things which men have not experienced through the senses, they happen to have opinions rather than understanding, as we learn from experience. For having thought of some city before seeing it, we find on arriving there that it is quite different than we had thought.
And so I believe we have only an opinion about those forms like rationality, mortality, paternity, or what is within. Names for what we experience, however, produce understanding to the extent they can do so, for the one who coined the terms intended that they be imposed in accord with the [true] nature or properties of things, even though he himself was unable to do justice in thought to the nature or property of the thing. It is these common concepts, however, which Priscian calls general and special [i.e. generic and specific], that these general names or the names of species bring to the mind. He says that the universals function as proper names with regard to such conceptions, and although these names refer to the essences named only in an indiscriminate fashion, they direct the mind of the hearer immediately to that common conception in the same way that proper names direct attention to the one thing that they signify.
Porphyry too, in distinguishing between things constituted only in the likeness of matter and form and those actually composed of matter and form, seems to understand this common conception by the former. Boethius also, when he calls the conception gathered from a likeness of many things a genus or a species, seems to have in mind this same common conception. Some think that Plato subscribed to this view, i.e. to these common ideas which he located in the nous he gave the names of genus and species. On this point, perhaps, Boethius indicates some disagreement between Plato and Aristotle, where he speaks of Plato claiming not only that genera, species, and the rest should be understood to be universals, but also that they also have true existence and subsistence apart from bodies, as if to say that Plato understood these common concepts, which he assumed to exist in a bodiless form in the nous, to be universals. He means here by universal “a common likeness of many things” perhaps, rather than “predicable of many” as Aristotle understood the term. For this conception [itself] does not seem to be predicated of many in the way that a name is able to be applied to each of many things.
But his [i.e. Boethius’] statement that Plato thinks universals subsist apart from sensibles can be interpreted in another way, so that there is no disagreement between the philosophers. For Aristotle’s statements about universals always subsisting in sensibles is to be understood of the way they actually do exist, because the animal nature (which the universal name “animal” designates and which is called a kind of universal in a transferred sense of the term) is never found to exist in anything which is not sensible. Plato, however, thinks this nature has such a natural subsistence in itself that it would retain its existence if it were not subject to sense [i.e. if it were not clothed with sensible accidents]. Hence what Aristotle denies to be actually the case, Plato, the investigator of the nature, ascribes to a natural capacity. Consequently there is no real disagreement between them.
Reason too seems to agree with these authorities in their apparent claim that the universal names designate these common concepts or forms. For what else does to conceive of them by name mean but that names signify them? But since we hold that these forms conceived are not simply the same as the acts of knowing them, there is in addition to the real thing and the act of understanding a third factor, viz. the signification or meaning of the name. Now while there is no authority for holding this, still it is not contrary to reason.
At this point, let us give an answer to the question we promised earlier to settle, namely whether the ability of universal words to refer to things in general is due to the fact that there is in them a common cause for imposing the words on them, or whether it is due to the fact that a common concept of them exists, or whether it is for both of these reasons. Now there seems to be no ground why it should not be for both of these reasons, but if we understand “common cause” as involving something of the nature of the things, then this seems to be the stronger of the two reasons.
Another point we must clarify is the one noted earlier, namely that these universal conceptions are formed by abstraction, and we must show how one can speak of them as isolated, naked, and pure without their being empty. But first about abstraction. Here we must remember that while matter and form are always fused together, the rational power of the mind is such that it can consider matter alone or form alone or both together. The first two are considerations by way of abstraction, since in order to study its precise nature, they abstract one thing from what does not exist alone. The third type of consideration is by way of synthesis. The substance of man, for instance, is a body, an animal, a man; it is invested with no end of forms. But when I turn my attention exclusively to the material essence of a substance, disregarding all its additional forms or qualifications, my understanding takes the form of a concept by abstraction. If I direct my attention, however, to nothing more than the corporeity of this substance, the resulting concept, though it represents a synthesis when compared with the previous concept (that of substance alone), is still formed by abstraction from the forms other than corporeity, such as animation, sensitivity, rationality, or whiteness, none of which I consider.
Such conceptions by abstraction might appear to be false or empty, perhaps, since they look to the thing in a way other than that in which it exists. For since they consider matter or form exclusively, and neither of these subsists separately, they clearly represent a conception of the thing otherwise than the way it is. Consequently, they seem to be vacuous, yet this is not really the case. For it is only when a thing is considered to have some property or nature which it does not actually possess that the conception which represents the thing otherwise than it is, is indeed empty. But this is not what happens in abstraction. For when I consider this man only in his nature as a substance or a body, but not as an animal, a man, or a grammarian, certainly I do not think of anything that is not in that nature, and still I do not attend to all that it has. And when I say that I attend only to what is in it, “only” refers to my attention and not to the way this characteristic exists, for otherwise my conception would be empty. For the thing does not only have this, but I only consider it as having this. And while I do consider it in some sense to be otherwise than it actually is, I do not consider it to be in a state or condition other than that in which it is, as was pointed out earlier. “Otherwise” means merely that the mode of thought is other than the mode of existing. For the thing in question is thought of not as separated, but separately from the other, even though it does not exist separately. Matter is perceived purely, form simply, even though the former does not exist purely nor the latter simply. Purity and simplicity, in a word, are features of our understanding, not of existence; they are characteristic of the way we think, not of the way things exist. Even the senses often function discriminatively where composite objects are concerned. If a statue is half gold, half silver, I can look separately at the gold and silver combined there, studying first the gold, then the silver exclusively, thus viewing piecemeal what is actually joined together, and yet I do not perceive to be divided what is not divided. In much the same way “understanding by way of abstraction” means “considering separately” but not “considering [it] as separated.” Otherwise such understanding would be vacuous….
But let us return to our universal conceptions, which must always be produced by way of abstraction. For when I hear “man” or “whiteness” or “white,” I do not recall in virtue of the name all the natures or properties in those subjects to which the name refers. “Man” gives rise to the conception, indiscriminate, not discrete, of animal, rational and mortal only, but not of the additional accidents as well. Conceptions of individuals also can be formed by abstraction, as happens for example when one speaks of “this substance,” “this body,” “this animal,” “this white,” or “this whiteness.” For by “this man,” though I consider just man’s nature, I do so as related to a certain subject, whereas by “man” I regard this nature simply in itself and not in relation to some one man. That is why a universal concept is correctly described as being isolated, bare, and pure: i.e “isolated from sense,” because it is not a perception of the thing as sensory; “bare,” because it is abstracted from some or from all forms; “pure,” because it is unadulterated by any reference to any single individual, since there is not just one thing, be it the matter or the form, to which it points, as we explained earlier when we described such a conception as indiscriminate.
Now that we have considered these matters, let us proceed to answer the questions posed by Porphyry about genera and species. This we can easily do now that we have clarified the nature of universals in general. The point of the first question was whether genera and species exist. More precisely, are they signs of something which really exists or of something that merely exists in thought, i.e. are they simply vacuous, devoid of any real reference, as is the case with words like “chimera” or “goat-stag,” which fail to produce any coherent meaning? To this one has to reply that as a matter of fact they do serve to name things that actually exist and therefore are not the subjects of purely empty thoughts. But what they name are the selfsame things named by singular names. And still, there is a sense in which they exist as isolated, bare, and pure only in the mind, as we have just explained….
The second question, viz. “Are they corporeal or incorporeal?” can be taken in the same way, that is, “Granting that they are signs of existing things, are these things corporeal or incorporeal?” For surely everything that exists, as Boethius puts it, is either corporeal or incorporeal, regardless of whether these words mean respectively: (1) a bodily or a bodiless substance, (2) something perceptible to the senses like man, wood, and whiteness, or something imperceptible in this way like justice or the soul. (3) “Corporeal” can also have the meaning of something discrete or individual, so that the question boils down to asking whether genera and species signify discrete individuals or not. A thoroughgoing investigator of truth considers not only what can be factually stated but also such possible opinions as might be proposed. Consequently, even though one is quite certain that only individuals are real, in view of the fact that someone might be of the opinion that there are other things that exist, it is justifiable to inquire about them. Now this third meaning of “corporeal” makes better sense of our question, reducing it to an inquiry as to whether it is discrete individuals or not that are signified. On the other hand, since nothing existing is incorporeal, i.e. nonindividual, “incorporeal” would seem to be superfluous in Boethius’ statement that everything existing is either corporeal or incorporeal. Here the order of the questions, it seems, suggests nothing that would be of help except perhaps that corporeal and incorporeal, taken in another sense, do represent divisions of whatever exists and that this might also be the case here. The inquirer in this case would seem to be asking, in effect: “Since I see that some existing things are called corporeal and others incorporeal, I would like to know which of these names we should use for what universals signify?” The answer to this would be: “To some extent, ‘corporeal’ would be appropriate, since the significata are in essence discrete individuals. ‘Incorporeal’ would be a better description, however, of the way a universal term names things, for it does not point to them in an individual and specific fashion but points only in an indiscriminate way, as we have adequately explained above.” Hence universal names are described both as corporeal (because of the nature of the things they point to) and as incorporeal (because of the way these things are signified, for although they name discrete individuals, universals do not name them individually or properly).
The third question (“Do they exist apart from or only in sensible things?”) arises from the admission that they are incorporeal, since, as we noted [in the opening paragraph], there is a certain sense in which “existing in the sensible” and “not existing in the sensible” represent a division of the incorporeal. Now universals are said to exist in sensible things to the extent that they signify the inner substance of something which is sensible by reason of its external forms. While they signify this same substance actually existing in sensible garb, they point to what is by its nature something distinct from the sensible thing [i.e. as substance it is other than its accidental garb], as we said above in our reinterpretation of Plato. That is why Boethius does not claim that genera and species exist apart from sensible things, but only that they are understood apart from them, to the extent namely that the things conceived generically or specifically are viewed with reference to their nature in a rational fashion rather than in a sensory way, and they could indeed subsist in themselves [i.e. as individual substances] even if stripped of the exterior or [accidental] forms by which they come to the attention of the senses. For we admit that all genera and species exist in things perceptible to the senses. Since our understanding of them has always been described as something apart from the senses, however, they appeared not to be in sensible things in any way. There was every reason, then, to ask whether they could be in sensibles. And to this question, the answer is that some of them are, but only to the extent, as was explained, that they represent the enduring substrate that lies beneath the sensible.
We can take corporeal and incorporeal in this second question as equivalent to sensible and insensible, so that the sequence of questions becomes more orderly. And since our understanding of universals is derived solely from sense perceptions, as has been said, one could appropriately ask whether universals were sensible or insensible. Now the answer is that some of them are sensible (we refer here to the nature of those things classed as sensible) and the same time not sensible (we refer here to the way they are signified). For while it is sensible things that these universals name, they do not designate these things in the way they are perceived by the senses, i.e. as distinct individuals, and when things are designated only in universal terms the senses cannot pick them out. Hence the question arose: “Do universals designate only sensible things, or is there something else they signify?” And the answer to this is that they signify both the sensible things themselves and also that common concept which Priscian ascribes above all to the divine mind.
As for the fourth question we added to the others, our solution is this. We do not want to speak of there being universal names when the things they name have perished and they can no longer be predicated of many and are not common names of anything, as would be the case when all the roses were gone. Nevertheless, “rose” would still have meaning for the mind even though it names nothing. Otherwise, “There is no rose” would not be a proposition.»
– Pierre Abélard (1079-1142), Logica Ingredientibus, pp. 178-188.