1. Having laid down some principles for discussing God’s Eternity, Thomas concludes his investigation of the characteristics of the Divine Essence with a quick discussion of God’s one-ness (unitas). If one is looking out for the transcendentals (being, one, true, good), this is the third transcendental we have discussed so far. As we begin the eleventh question, we must tremble a little in anticipation of the three that follow it (12, 13, 14), each of which is mammoth and extremely dense.
2. He begins his discussion of the divine unity by asking whether the notion “one” adds anything to the notion of “being” (ens). He provides three objections: First, that “one” is the basis of a genus of quantity, i.e. the unit, and as such it is distinguished from all other quantities somehow. But every genus or kind of thing is divided from “being” by having something added to it, so “one” must add something to the notion of being.
3. The second objection is from the fact that being is divided in general into “one” and “many”, so that whatever is many is not one, and vice versa. But again the division of being into two genera requires the addition of some distinguishing feature of each genus, so “one” must add something to being.
4. Third, he points out that if “one” adds nothing to “being” then the terms would be equivalent, and when we said “one being” we would merely be saying “being being”, which is stupid.
5. For the Sed Contra, he cites a fine passage from Denys. “Nihil est existentium non participans uno.”
6. In the Corpus he explains that “one” is a negative term which excludes division, so it need not add anything to “being”. He then proves that every being is one: Things are either simple or compound. If they are simple, then they are undivided by virtue of their simplicity. If they are compound, then they exist as compounds only insofar as they are taken together (since the dissolution of a composite destroys it as a composite). Thus everything is one.
7. The replies to the objections are more interesting. To the first he says that we need to distinguish between “one” as convertible with being and “one” the principle of a certain genus of quantity (i.e. the unit). If we conflate the two, and grant that “one” does not add anything to “being”, then we end up like Pythagoras, who believed that everything was somehow fundamentally number. If, on the other hand, we conflate them and assume that “one” does add something to “being”, we end up like Avicenna, who said that the “one” was an accident of things. Thomas seems to find this latter view especially contemptible. The solution, of course, is that “one” as number adds quantity (an accident) to the notion of a substance, whereas “one” as convertible with being adds nothing, but designates the substance of a thing as undivided.
8. In response to the second objection, he gives a discourse on the different modes of unity and multitude in things. A thing can be one simpliciter and many secundum quid if it is a single substance with many accidents, for example. Or it can be many simpliciter and one secundum quid if multiple subjects are united in sharing some particular cause, quality, or orientation. This is how “being” is divided into “one” and “many”. But everything that is is in some way one, even every multitude. He quotes Denys: “But what are many in their parts are one in their whole; and what are many in accidents are one in subject; and what are many in number are one in species; and what are many in species are one in genus; and what are many in procession are one in principle.”
9. He replies to the third that it is not pointless to say “one being” because “one” adds something secundum rationem, i.e. in the aspect under which it is considered, to being.
OUTLINE OF ARTICLE
- “One” is a genus of number.
- “One” and “many” divide being.
- If “one” adds nothing to “being”, then saying “one being” is redundant.
- “One” is negative: it excludes division.
- Simple things are one by their simplicity.
- Composite things are one in their composition.
- Everything is one.
- The “one” of number is distinct from the “one” convertible with being. The former adds an accidental quantity to a thing; the latter designates the unity of its substance.
- Every multitude is in some way “one”.
- “One” considers “being” under a different aspect.