Aquinas on the Distinction Between 'Esse' and Essence: A Brief Reply to Kenny

           In his book Aquinas, while discussing Aquinas's conception of being, Anthony Kenny rightly raises a question concerning one portion of the coherence of Aquinas's account. In particular, his objection has to do with the very idea of the distinction between esse and essence. One may state it as follows. Part of Aquinas's account, that of God conjoining a creature's essence with an individual act of existence raises the question of what exactly it is that God does when he creates something, i.e., when he brings something into being ex nihilo, to use the traditional term.

            It cannot be the case that he actualizes a passive potency in a non-existing essence; for, in this case, there is no 'thing' there for him to actualize. That is, it cannot be

... that long before Adam and Eve were created there already were such things as the essence of Adam and the essence of Eve; and that the creation of Adam and Eve consisted precisely in God's giving existence to these essences, actualizing their potentialities.[1]
 

Moreover, even if one were to concede that it were possible for God to actualize a non-existing potency, whatever this would involve, Kenny could also object that the idea is still incoherent, since there is no actualization, he can claim, without individuation.

            Here, however, Kenny might be too quick in assuming that this is the only way that God, according to Aquinas, could bring about the state of affairs in which some thing goes from non-existing, i.e., being merely potential with respect to existence, to actually existing. For perhaps it makes sense to distinguish between God's bringing it about that the essence of Adam goes from potentially existing to actually existing and God's bringing it about that Adam himself goes from potentially existing to actually existing. Surely, if God can as much as form the concept of Adam, God can bring it about that Adam begins to exist. It is true that in this case God does not conjoin the pre-existing essence of Adam to an individual act of existence, but the reason for this should not be hard to figure out.

            For Aquinas holds that a substance, in the sense of an individual material substance, is individuated by its matter. And if a substance is individuated in this way, the 'essence' of Adam does not and cannot exist in such a way that it preexists its matter. For it is precisely in virtue of its matter that it is made into the very individual thing (of a certain species) that it is. But while the 'essence' of Adam cannot exist without Adam's (the form-matter composite's) first existing, there do not seem to be similar obstacles to one's claiming that the concept of Adam exists such that one can actualize the thing that (if it existed) would correspond to that concept, i.e., Adam.

            One way in which God could bring about Adam's existence would involve God's bringing Adam into existence wholesale. In this case, God simply creates a man with such and such features in such and such a way that this individual matches the concept of Adam that God forms in his mind. Alternatively, God could bring Adam into being by creating an individual human soul or form and conjoining it to an individual piece of matter that is sufficient for forming the characteristics and qualities that God wants Adam to have. One potential worry about this proposal, however, is that God could potentially create two individuals who match the concept of Adam that he forms in his mind: Adam-1 and Adam-2. Both individuals are, one might say, indistinguishable to the naked eye, and their behavior is practically indistinguishable such that only God can tell the two apart. It seems, in this case, that either individual has an equally strong claim to being Adam.

            But what exactly is this last point supposed to show? For it is also true that God could make an exactly similar duplicate of me as I now sit typing at my desk. But it does not follow from this that my duplicate would also be me. Here, one is likely to protest that the question at hand is not whether God's creating a duplicate of me, who already exists, and is thereby already individuated, would in consequence create another person who would have an equally strong claim to be me. The question, rather, was why, given the fact that there is no 'thing' which corresponds to God's concept of Adam prior to the time at which God creates Adam, does Adam-1 have a stronger claim to being Adam than Adam-2?

            My answer to this question is that if God can make actual everything about the concept of Adam that exists in God's mind, then God can make actual the matter in virtue of which his concept of Adam has the features that it has. That is, if it is matter that gives to individuals those features in virtue of which they differ from one another, then the matter that makes Adam the individual that he is is already implicitly contained in God's concept of Adam. And if no two individuals can have exactly the same matter at exactly the same time, this is sufficient for individuating, in Aquinas's terms, two otherwise qualitatively exactly similar persons who exist at the same time.

            But what about two exactly similar persons, in terms of qualitative similarity, who possess the exact same matter at two distinct times? Here, one can set down the details such a situation would involve by imagining the following. First, God could create Adam-1 at a certain time t such that he brings Adam-1 into being by means of creating an individual human form or soul at t, soul-1, let's say, and joins it to a certain individual piece of matter, let's call it matter-1, that is sufficient for producing a certain set of qualities q (what one might call a person's q-set) in the human being who results at t from the union of soul-1 and matter-1 at t. The human being whom God brings into being at t from the creation of soul-1 and matter-1 is Adam-1. Continuing the example, let's assume that Adam-1 goes out of existence, i.e., dies, at a later time t1.

            Here, the soul of Adam-1, according to Aquinas, would continue to live on, and, for the moment, we do not have need to question this suggestion. The matter, matter-1, that originally belongs to Adam-1 will continue to exist qua matter, but it will be changed from Adam-1's body at the time of Adam-1's death by its being joined to a new substantial form such that matter-1 ceases to be living human flesh and becomes something else, i.e., dead human flesh. Now, matter-1 will continue to change from this time on following t1 as it acquires new substantial forms. But let's assume, for simplicity's sake, that during this process the exact matter, in terms of the quantity or amount of matter, that makes up matter-1 stays the same.

            Now, assume that at a later time t2, God creates a new human being, Adam-2, by taking matter-1 and joining it to a new human soul, soul-2. At t2, then, a new human being, Adam-2, comes into existence in virtue of the union of soul-2 and matter-1. Adam-2 will have the same q-set that Adam-1 had in virtue of Adam-1's having matter-1. What, now, makes Adam-1 distinct from Adam-2 such that one can say that Adam-2 is not Adam-1? There are two things, I think. First, the fact that Adam-1 and Adam-2 have two distinct human souls or forms. It is true, in fact, that Adam-1 and Adam-2 have the same q-set in virtue of having the same matter, matter-1. But there is room to question, I think, whether this truly makes them the same individual.

            By the falsity of the identity of indiscernibles, they are not the same person. So, on this basis, one might distinguish between something's being a principle of individuation and something's being a principle of identity. A principle of individuation, one might claim, is that in virtue of which something counts as exactly one individual of a certain type or kind. A principle of identity is that in virtue of which an individual of a given type is the exact individual that it is. While in many cases a principle of individuation will work as a rough guide in terms of figuring out the identity of a given individual, one might protest that it is not sufficient for determining its identity. And in this particular case, it is the individual soul of the person, Adam-1, or at least I submit, in virtue of which Adam-1 is the exact individual that he is. Thus, even if one assumes that Adam-1 and Adam-2 are qualitatively indiscernible, it will not follow that they are the same individuals. 

            But concede for the sake of argument that a principle of individuation is sufficient for also determining identity. Thus, the second idea I have in mind for distinguishing Adam-1 and Adam-2 is that while it is true that they have the same matter, it is not true that they have the same matter at the same times, but only at two distinct times. More accurately, they have the same matter, matter-1, throughout two distinct durations of time, and this, I submit, is sufficient for marking them out as two distinct individuals. But in this case, one might protest, isn't this just an instance of intermittent existence? I do not believe so. Intermittent existence would involve exactly the same individual existing in the following way, say, from times t to t1, beginning to exist at t and ceasing to exist at t2, while "resuming" existence at a later time t3. But if possession of matter, in this case matter-1, throughout a duration of time is sufficient for determining the identity of a single individual, it is also sufficient for distinguishing two individuals that possess the same particular matter at two distinct times.  

            One final point I want to consider before closing concerns the sense in which God brings something from potentially existing to actually existing. For I have yet to address in what exact sense, then, that one can distinguish between a thing's existence and its essence. And I have effectively conceded to Kenny that the idea of God's conjoining a creature's individual essence to an individual act of existence does not make sense.

            To bring out the distinction in the way I think makes sense, one needs to note that there are two distinct senses in which one can say that something is in potency. One might say that something is in potency of a certain type F to a specific actuality of a certain type F. Alternatively, one might say that something is in absolute potency, full stop, such that it does not have any potency at all, because the thing simply does not exist. In this sense, it is incorrect to say that the thing is in potency (first sense), because potency, here, presupposes something which is the subject of the possible change, i.e., it has passive powers, one might say, in virtue of which it is the subject of possible change. But (in this second sense) there is no subject at all, and thus no subject of possible change.

            Here, to make sense of Aquinas's doctrine, I submit that one must understand 'potency' in the second sense in broader terms than merely those suggested by the 'act' 'potency' distinction as it applies to particular substantial forms or to accidental qualities. In particular, I believe one should read Aquinas as meaning potency in a more absolute sense, in terms of existence itself, or with respect to things that lack existence, absolute possibility in the sense of metaphysical possibility. God actualizes a thing's potency to exist, then, by first conceiving of the thing in the sense in which I described him as conceiving of Adam, and then bringing it about that the thing in question begins to exist.