Esse
| Latin | Esse; actus essendi |
|---|---|
| Treatise | Summa theologiae I, q. 3 a. 4; De ente et essentia cc. 4–5 |
| Controlling authority | Catechism 199–221; Dei Filius |
| Doctrinal standing | God is; creatures receive being; esse as a technical act is Thomistic |
| School | Thomism |
Esse is, in Thomism, the act of existing by which an essence is actual rather than merely possible, identical with the divine essence in God and received in every creature.[1]
The act by which a thing is
Essence answers what a being is. Esse answers that it is. The two questions are not the same. One can know what a phoenix would be without knowing that any phoenix exists. In Thomism existence is not a further accidental predicate glued to a complete thing. It is the act of the essence, the actuality of all form or nature, as Aquinas says in Summa theologiae I, question 3, article 4.[2]
The 1913 Catholic Encyclopedia article on essence and existence describes existence as that whereby the essence is an actuality in the line of being, removing it from the merely possible and placing it outside its causes. St. Thomas describes it as the first or primary act of the essence as contrasted with its secondary act or operation. That contrast is scholastic. It names the difference between being and operating, not two rival religions inside the creature.[3]
Ipsum esse subsistens
In God essence and existence are identical. He does not have being as something received into a prior nature. He is ipsum esse subsistens, subsistent being itself. The Catechism receives this confession when it teaches that God's essence is to be, and that he is the fullness of being without limit, potency, or dependence. Divine names such as wise and good do not add accidents to that essence; they name the one simple act analogically.[1]
Because God's essence is his existence, the proposition God exists is self-evident in itself, though not to us who do not see that essence. Question 2 of the Prima pars therefore demonstrates existence from effects. Question 3 then shows that in the cause so reached there is no composition of essence and esse. The sequence is philosophical theology serving the dogma of divine simplicity and aseity.
Received act in creatures
De ente et essentia, chapters 4 and 5, argues that if a creature's essence included existence, the creature would be necessary being and could not be caused. Because creatures are caused, their existence is other than their essence and must come from the first cause whose essence is existence. Every finite essence exists by an act measured to it. That act is from God. Conservation is the same gift continued, not a stored fuel.[4]
Esse is limited by the essence that receives it, as act is limited by potency. An angel has an essence distinct from its act of existing even though it is not composed of matter and form. A corporeal substance is further composed of matter and form, yet that pair still does not explain why the composite exists rather than not. Participation is this received act referred to the unparticipated source.
Not a laboratory layer
Esse is not a detectable particle, energy, or measurable stratum inside a body. Scientific investigation studies the operations and accidents of existing things. Metaphysics asks why there is an actual essence at all. Confusing the two orders produces either a cartoon of scholasticism or a refusal of metaphysical questions in the name of method. Fides et Ratio defends the legitimacy of the question.[5][6]
The technical term is a school instrument. The truths it protects are not optional: God is not one being among beings; creatures are real, good, and caused; prayer does not add to God; grace is a created participation, not a piece of the divine esse inserted into the soul. Other Catholic philosophies must still confess those truths if they decline the vocabulary of actus essendi.[6]
References
- Back to citation occurrence 1.0 Back to citation occurrence 1.1 Catechism of the Catholic Church, 199–221 — Authoritative confession of the one God, his simplicity, fullness of being, and the identity of his essence with his existence.
- Back to citation Thomas Aquinas, Summa theologiae I, question 3, article 4 — Primary treatment of divine simplicity, including the identity of essence and existence in God and the received existence of creatures.
- Back to citation Catholic Encyclopedia (1913), Essence and Existence — Public-domain account of essence as that whereby a thing is what it is, existence as its actuality, and the disputed real distinction in creatures.
- Back to citation Thomas Aquinas, De ente et essentia, chapters 1 and 4–5 — Primary early treatise on essence, quiddity, and the real distinction of essence and existence in substances other than God.
- Back to citation First Vatican Council, Dei Filius — Dogmatic constitution on God the Creator, the natural knowability of God, the distinction of the natural and supernatural orders, and the gratuity of revelation.
- Back to citation occurrence 6.0 Back to citation occurrence 6.1 John Paul II, Fides et Ratio — Encyclical on the harmony of faith and reason, the enduring value of Aquinas, metaphysical realism, and legitimate philosophical plurality within Catholic faith.