De Moor IV:24: Against Composition in God
Moreover, in this Single Essence there is no Real Composition, either of the Nature and Attributes, or of the Attributes among themselves. Real Composition, says our AUTHOR, while admitting in § 18 the Difference of the Reason Reasoned, whereby the Attributes are distinguished from the Essence according to the reckoning of the Objects and Effects, and according to our Manner of Conception, is also held to admit such a Composition of the Reason Reasoned according to our Manner of Conception: but our Manner of Conception comes rightly to be distinguished as imperfect with respect to the thing itself, as it is in God: consult VRIESIUS’ Determinationes Ontologicas, chapter XIII, § 2-5, 11.
But here no Real Composition obtains; whether, α. that is called Physical, which sort is, either, 1. from Integrating Parts, when some parts are beside other parts, as, for example, the human body is composed of a head, chest, arms, etc.: or, 2. from Matter and Form, which are called Essential Parts, which differ in substance, but not in place, of which sort are the soul and body in man. Neither of which is applicable to the Incorporeal God, since Integrating Parts are proper to Bodies alone: and, granting that Spirits are also contemplated as Matter in which, that is, subject, as the soul is the matter in which of its own abilities and habits, so likewise Matter about which, that is, object: Nevertheless, Matter from which, which is a cause, and is especially applied in the Composition of Matter and Form, is applicable to Bodies alone. Or it is, β. a Logical Composition, 1. that is, of Genus and Difference of Species, of which two Logicians teach to construct Definitions: thus man is a rational Animal, in which Animal is the genus; Rationality is the difference of species, whereby man is distinguished from beast. And, although this is said to be a Composition of Reason only, not Real, because Universals, as a Genus, are only Entities of Reason: nevertheless, it does not fall unto God, to whom Univocal Genus and Difference of species is not able to be assigned, as we saw in § 11. Or, 2. also from Subject and Accident, as in the case of a learned man Composition of the Subject obtains, because he is a man, with learning as an Accidental Property, which quality or habit is added to the man further to perfect him; which sort of thing has no place in the Being Altogether Perfect of itself. Or, finally, γ. it is a Metaphysical Composition, which is discussed in Ontology, 1. of Act and Potency, which is present in all composition, in which one part always perfects the other, and is in turn perfected by the first; for they are wont to say that one part is in the mode of Act, the other in the mode of Potency: thus in the Composition of subject and adjunct, for example, the adjunct is called Act, because it perfects the subject; but the subject is called Potency, because it is perfected by the adjunct; thus man is the subject of beauty, because the adjunct further perfects the subject. And that is said to be in Potency, whatever is suited by acting or receiving to acquire further perfection: but perfection is called Act, completing by its admittance Potency. But nothing is able newly to be added to God, an Altogether Perfect and Immutable Being, inasmuch as it would be received by His Essence unto His greater perfection. Whence God is called Pure Act, that is, pure, unmixed Perfection, to whom no Potency, or aptitude to receive perfection, is applicable. Although under the name of Act here it would also be fitting to exclude all thought, as if it were another composing part, in which sense it is opposed to Potency. 2. Our AUTHOR additionally mentions composition from Essence and Existence. This Compositions is so subtle that some do not at all admit it, but hold Essence and Existence as mere synonyms, which sort are of the same origin: and there is not anything having its Essence in act, that does not at the same time enjoy Existence, since Existence sums up the first and, as it were, constitutive concept of Being. Nevertheless, since non-existent Possible things are also able to be defined, like snow in summer, a rose in winter, those are said to have Essence with others even then, when they do not exist: while verily that Essence of a possible thing, as long as it does not exist, is merely Potential: and the Definition of it is not so much an explication of Essence, which would now actually be in the thing defined, as indeed an explication of those predicates that are involved in the Essential concept that we have of the thing. But no composition of any sort between Essence and Existence, so that Existence might be considered as something diverse from the Essence of a Being, and, as it were, superadded to it, falls to God, to whom as a Necessarily-Existing Being potential Essence, separated from actual Existence, is not able to be attributed; since it is actually contradictory merely to conceive of God in the mind as Non-Existent, because the Essence of God implies His Necessary Existence: see § 21.