(From De Ente et Essentia)
Essence and Universal are treated of in the third Chapter of St Thomas' De Ente et Essentia.
Before this chapter he had found that the Essence of composed substances itself is also composed, namely of matter and form, in which matter is considered as not-delimited ( materia non signata ). The ontological composition always refers to an ontological composition, i.e. a composition, not of things, but of principles of being. Normally there are two of them, a substrate-principle and a principle of in-formation. Such a dual structure we can call catallel, which means in this context : consisting of two factors that complement each other.
The Essence is known in the form of a definition which itself consists of genus + difference, and as such is the definition of the species.
Individuation is accomplished by matter that becomes delimited ( materia signata ).
Chapter 3 investigates in what way this Essence is related to the Universal, namely genus, difference and species. So St Thomas asks himself whether the Essence itself is universal or not, and if so, under which conditions (of consideration). Thus we are presented here with St Thomas' view of the well-known Problem of Universals.
For a more thematic (i.e. non-historical) treatment of the Universal, see the Essay on the Universal in the First Series of Essays.
Here I will treat of the Thomistic view without any critique, mainly as it is exposed in Chapter 3 of St Thomas' De Ente et Essentia. But before doing so I will nevertheless add some general critical notes.
According to St Thomas, Essence can be considered in an absolute way, i.e. wholly in itself and exclusively in itself. With respect to Man he accordingly assumes that within Socrates-for-example there is something, by virtue of which Socrates is a human being, i.e. a rational animal ( animal rationale ). This also applies to Plato, Peter, etc. To this Essence, according to him, a number of items could happen to be allotted, without strictly belonging to it, for example unity and multitude.
Multitude does not belong to Essence, taken absolutely, because that Essence (for instance the Essence in Socrates), is not many, but one.
Unity does not belong to Essence, taken absolutely, because otherwise one Essence would belong to Socrates as well as Plato, etc., resulting in their all being one. The Essence then could not be multiplied. An Essence can reside in something, either in this extramental individual thing, or in that extramental individual thing, or it can reside in the intellect, and in this case either in this individual intellect, or in that individual intellect.
This RESIDING IN does not pertain to the Essence, taken absolutely, but could happen to be allotted to the Essence. The character of universality also does not pertain to the Essence, taken absolutely, because universality implies unity and communicability ( communitas ), and these do not pertain to the Essence, taken absolutely. Communitability does not pertain to the Essence, taken absolutely, because the Essence, for instance HUMAN BEING, among others resides in Socrates, and there it is the Essence of Socrates and that is not communicable, because this Essence is individuated in Socrates. All this also applies to the genus and the species, i.e. that they are not the Essence, because we find the Essence in individuals, for example in Socrates, not as unity-referring-to-many-other-cases, which, after all is demanded by the character of genus and species, being universals. Consequently the Essence, insofar as it is in the extramental individuals, cannot be genus or species. Thus the species as species (thus as a universal) must come together with (i.e. must be equivalent to) the Essence insofar as this is in the intellect, because the Essence, insofar as residing in the intellect, abstracts from all individuating (conditions), and because of that it can be one (Thus is already one condition for being universal satisfied). This Essence, as residing in the intellect, can therefore uniformly refer to all the relevant extramental individuals, by way of a similitude with respect to those individuals. A simulitude among things means that there are aspects that are different, and also aspects that are (precisely) the same among them. Schematically we can represent this as follows :
The Essence K, as residing in the intellect, then can refer to AK, BK, CK and EK (And now also the second condition for being universal is satisfied, namely communicability). The universality of the Essence-residing-in-the-intellect is not accomplished by this "residing-in-the-intellect" alone, thus not exclusively by the fact that the Essence (in the cognitive act) resides in the intellect, but also by (i.e. in combination with) the fact that this Essence refers to the many relevant extramental individual things, as a similitude of them. The Essence, as it is in the intellect, intends these extramental things, or perhaps better expressed : intends something within those extramental things. The Essence K is repeated over the individuals : AK, BK, CK, DK, etc. We speak here about "the Essence" as if it were one thing. But the only reason that we do so here is the identity with respect to content of K in AK, BK, CK, DK, etc. This Essence K is not numerically one, it is directly many (as an aspect that happens to be allotted to this Essence, absolutely taken) :
The Essence (as residing) in the intellect (always in an individual intellect which finds itself in the act of knowing) is one, and because just this one-something refers to many things (i.e. represents those many things, or perhaps better expressed : represents something in those many things) this essence (as residing in the intellect) is a universal. It is one, referring to many things :
It is important to note that according to Thomism there can be collections of things, say the collection A, in such a way that there is something -- let us call it K -- in those things of such a collection, which is identical-with-respect-to-content for all those things belonging to that collection. And this K is discovered by the intellect (in cooperation with the senses). And now the intellect can abstract K from those things, and, as it were, absorb it (into itself). And now that something, -- which it accordingly has absorbed, and insofar as it is now in that intellect, while referring to those things, -- the intellect interprets as a species (in the case of, say, HUMAN BEING), or as a genus (in the case of, say, ANIMAL), or as difference (in the case of, say, RATIONAL).
Whether this repetition of that something over individual things is exact with respect to content, or not, has not been investigated in Thomism. A non-exact repetition can be symbolized as follows. It concerns (in this symbolization) the non-exact repetition of a segment beginning with D and ending with T :
...UVDAEAAAAAAAATFG...
...HIDABAAAAAAAATLM...
...SNDAAAAAACAAATOP...
...RRDAAAAAAAAXATIA...
...JYDAAAEEAAAAATZB...
etc.
Here, indeed, something is repeated, but not exactly. We cannot beforehand rule out this possibility, i.e. the possibility that the repetition is never exact. Nevertheless it seems unlikely : Things seem to possess a certain inherent and intrinsic nature, causing them to behave always in certain well specifiable ways.
Let me dwell on this a little longer.
All (say) copper crystals possess an internal structure such that it is a periodic pattern of chemical motifs, that can be described by a socalled Space Group (See Chapter IV, Crystals and the Substance-Accident Metaphysics). Moreover it has a certain chemical composition (in our case it consists of the chemical element Copper).
Space Group + Chemical Composition precisely characterize and define such a crystal. So here we indeed have features that are exactly repeated over all copper crystal individuals (NOTE 1). These features are, however, caused, caused by some process generating those crystals, so they cannot be a nature if we interpret such a nature as the essence of such crystals, because the essence should not be something derived, but be prior to all empirically detectable features in such crystals. So this nature must reside at a different ontological level than do the features it causes.
Epistemologically of course such a common nature, that could be described in the form of a law dictating the structure and behavior of those crystals, is dependent on the observed common features.
In the Non-Classical Series of Essays we have elaborated on the status of such a nature.
In the Thomistic view of "Essence-absolutely-considered" a pecularity is evident :
The " residing-in" of this Essence in things is, according to that view, an Accident (i.e. it is per accidens ) with respect to this "Essence-absolutely-considered". Accordingly he says in Chapter 3 of De Ente et Essentia, from line 50 :
"This nature [ = the Essence ] has a dual being [ = has a dual existence ] : one in singular things, another in the soul, and both [ ways of being ] draw [ certain ] accidents to that nature just mentioned. In singular things it has, after all, a multiple being [ = existence ] [ which indeed is one of those accidents ] through the diversity of those singular things. But nevertheless is the being [ = existence ] of those things [ = all the cases of "residing-in" in those singular things ] not compulsive [ i.e. not necessary ] for that nature, according to its first consideration, namely the absolute [ consideration ]."This would mean that the "residing-in" of the Essence HUMAN BEING in Socrates is accidental with respect to this Essence-absolutely-considered. We could interpret this in the following way :
Precisely the human individuation conditions happen to be the receiver (substrate) of the Essence HUMAN BEING, i.e. the latter accidentally fell upon those conditions.
For these human individuation conditions it is, however, not accidental to become the substrate for the Essence HUMAN BEING.
And how are things when we mean by "Socrates" Socrates-insofar-as-just-Socrates, i.e. just an object named "Socrates"?
In this case the receiver of the Essence consists of all the Socratic individuation conditions. And also in this case the reception is accidental for the Essence (taken absolutely). The receiver should be Socrates minus HUMAN BEING, and consists indeed of all the Socratic individuation conditions :
Precisely the Socratic individuation conditions happen to be the receiver (the substrate) of the Essence HUMAN BEING.
For these conditions it is thus accidental to become the substrate for the Essence HUMAN BEING, it could have become the substrate for the Essence (of) RAT (like it happened for the rat named Socrates in the novel Willard).
Let us summarize :
To end up in a particular substrate, in the sense of ending up in this particular substrate S, and not in that particular substrate P, it is accidental for a particular Essence H taken absolutely.
For substrate S-insofar-as-S it is accidental to become the receiver of a particular Essence H taken absolutely.
For substrate S-for-example it is necessary to become the receiver for the Essence H taken absolutely, because with the expression "S-for-example" we already point to a certain group of individuals that are like S and including S.
In all this the substrate is equivalent to individuation conditions, individuating an Essence-considered-absolutely.
So here we have precisely shown why and how St Thomas must set a principle of individuation.
Essence + individuation conditions can result in Socrates or/and in Plato, Peter etc., depending on which individuation conditions the Essence ends up in.
In this (Thomistic) way the Essence plays a central ontological role. And, also, Essence (thus not : Essence + individuation conditions) cannot be individual. But it (insofar as residing in the extramental individual things) cannot be a universal either, as we have seen. As such this status corresponds to that of the substantial form of an ontologically composed thing in the interpretation of OWENS, J., 1978 (1951), The Doctrine of Being in the Aristotelian Metaphysics, p. 385. There this form is not individual, but "a this" (which is analogous, but not identical, to "individual").
This status of priority of the Essence -- in Thomism -- sharply contrasts with the view that the 'full-fledged' individual, the concrete singular individual thing, enjoys this priority. Whether this latter view is correct, and whether such an individual then must be interpreted as a here-and-now individuum, or as a 'historical' individuum ( = the ordinary view of an individuum, like for instance Socrates ) is, as we have seen, a problem.
The priority status of Essence can be expressed clearly in the following way :
In the Real World an Essence exists, for instance HUMAN BEING (Of course there exist many specifically different Essences), and that Essence can find itself under diverse conditions (NOTE 2) , for example, it could be in Socrates (i.e. it could happen to be in a 'Socrates-environment'), or it could be in Plato (i.e. it could happen to be in a 'Plato-environment'), etc. All this reeks somewhat of a platonic position. But, Aristotle, after all, was a pupil of Plato (and consequently also St Thomas, in a way, was a pupil of that same great philosopher).
The Essence HUMAN BEING is the nature of Socrates-for-example, which here means the nature of Socrates – the Greek philosopher – and/or the nature of the philosopher Plato (both, not as philosopher), etc. And we just saw that this nature is, according to St Thomas, such that for it it is extrinsic to be (i.e. to reside) in something. Why?
Because its very nature (i.e. the nature [ratio] of the Essence HUMAN BEING) does not necessarily imply it to be in something.
The problem with this is, however, that we again appeal to a nature : again, because we first considered the nature of, say, Socrates, and then consider the nature of that nature.
So it remains questionable whether we indeed can legitimately isolate an Essence, say, the Essence HUMAN BEING (i.e. the nature of Socrates, of Plato etc.), from that something of which it is the nature.
To avoid "a nature of a nature", we could stipulate that the nature of, say, the Essence HUMAN BEING is wholly identical to the Essence HUMAN BEING. And in the latter there is nothing that would necessarily imply it to be in something (else).
The Thomistic view about the relation between the universal and the Essence can be summarized as follows :
In order to be called a genus, species or difference, the Essence (of an ontologically composed substance) must be considered under the following points of view :