Aquinas on esse subsistens and the Third Mode of Participation

ACCORDING TO Thomas Aquinas, God alone is, by his very essence, esse—the act of existing. All other beings merely have, or participate, esse.¹ Since Thomas speaks of esse in different respects, a question arises regarding what, precisely, participation in esse entails.² Considering this question, John F. Wippel has observed that sometimes the esse that Thomas presents as participated in is esse commune, indicating that finite beings have merely a share in—and are not identical with—the full perfection signified by the term esse.³ At other times, he presents a created being’s own particular, intrinsic act of existing (actus essendi) as participated.⁴ And, at still other times, the esse Thomas seems to present as participated is esse subsistens: the self-subsisting esse that he identifies as God.⁵ I say “seems to present” because of Thomas’s own reluctance to speak of esse subsistens as participated. For a complete understanding of his metaphysics of participation, one must address not only the role of esse considered in each of these three respects but also the reason for Thomas’s aforementioned reluctance.

To begin, we should note that although Thomas avoids speaking directly of a “participation in” esse subsistens,⁶ he does at times speak of things as participating either in or of the First Being (primum ens) and the First Act (actus primus).⁷ And since Thomas identifies this First—namely, God—with esse subsistens, we could thus read him as indirectly acknowledging a participation in such esse.⁸ With that said, more commonly Thomas indicates that beings do not participate in the being who is esse subsistens. He tells us, for example, that God’s essence remains unparticipated (imparticipata) and unparticipable (imparticipabilis).⁹ Why, then, is Thomas willing on occasion to speak of created beings as participating in the First Being? The answer rests in his view that even though such beings do not and cannot share in God’s essence, they can and do share in a likeness (similitudo) of that essence. Hence, when Thomas speaks in terms of participation in regard to God, he more commonly does so by adding the important qualification that it is a participation in the likeness of God—in the likeness of the divine essence that is esse subsistens.

As I will show in this article, if we wish to understand how esse subsistens or its likeness could be participated, we need to consider this question in light of a distinction Thomas draws in his commentary on Boethius’s De hebdomadibus between three modes of participation. The third of these modes is that of an effect participating in its cause; it is according to this mode, I will argue, that Thomas sees God as in some sense participated. As an entry point to considering this mode of participation, I will start with a simple question: what is the “likeness” to which Thomas refers when he speaks of a participation in God’s likeness? Answering this question will not only clarify how finite beings can be said in a sense to participate in God (even though his nature is unparticipated), but it will also shed further light on participation in esse considered according to those other two respects noted above: esse taken as the intrinsic actus essendi of an individual created being and esse taken as esse commune, the common notion of created actus essendi.

To this end, this article will consist of four parts. The first part will examine why Thomas at times presents esse subsistens as unparticipated and unparticipable, as well as why he concludes that created beings nevertheless do participate in a likeness of that esse. The second part will begin to address both what this likeness is and what it means for created beings to participate in it. The third part will then consider how Thomas’s account of such participation fits into the structure of participation that he presents in his commentary on Boethius’s De hebdomadibus, with a focus on the third mode of participation identified there...