The way we think and speak about things is important, particularly when our thinking and speaking about those things intersects with how we think and speak about God. This is nowhere more true than when, delving to the very bottom of the barrel of diverse beings, we come to think of the nature of "being" itself. And when we find ourselves there considering the nature of being, it is especially important for us to be able to rightly distinguish between the nature of the divine Being Himself and the nature of all created being. One thing that will help us in this regard is clear definitions of and distinctions between the metaphysical concepts of being. Thus, I want to provide a few brief definitions and distinctions concerning the concepts of ens, esse, and essentia.
What's The Difference?
The first two concepts, ens and esse, are really just two ways of breaking down the concept of "being." The first way to consider the notion of "being" is to consider a "being" as a "whole subsisting entity."[1] By this is meant certain individual entities as they exist in reality (think of a particular rock, your aloe plant in the window sill, your dog Skippy, or your best friend Ned). You and your best friend Ned are human beings. You exist. You have substance. You have "being." This first concept of being is what is in Latin called ens. The second and intimately related notion of being is the concept of esse. This is the more abstract concept of the two, and has been nicely defined as "that by which anything that is exists."[2] That is, you and Ned exist. You have being. But, how do you exist? How do you have being? What is that constituent principle by which you are? The answer is, "being itself." Being as such is the principle by which you exist and are a human being. You are an individual existing human by virtue of your participating in the principle of being itself. Third and finally, we arrive at the concept of essentia, which logically "derives from the notion of being and signifies that which possesses esse."[3] Essentia is a "principle of a complete being (ens)," but does not subsist as an existing thing itself.[4] Rather, essentia is the principle "by which a being is what it is."[5] Dolezal summarizes all of this well when he writes, "In sum, the three terms, each applying to the same substance, possess roughly the following distinct connotations: ens denotes the subsisting thing itself (entitativeness); esse indicates that by which it is (isness); and essentia signifies that by which it is what it is (whatness)."[6]
[1] James E. Dolezal, God Without Parts: Divine Simplicity and the Metaphysics of God's Absoluteness, (Eugene: Pickwick, 2011), 95. This article is thoroughly indebted to Dolezal's work in the above cited book.
[2] Ibid, 96.
[3] Ibid.
[4] Ibid.
[5] Ibid.
[6] Ibid.