Question 1. Whether there can be along with the unity of the divine essence a plurality of persons

191. About the second part of this distinction a question is raised first whether there can be along with the unity of the divine essence a plurality of persons.

That there cannot be:

Because all things that are simply with one and the same thing simply the same are altogether the same with each other. And ‘simply’ is added because if they are not the same as the same simply but in a certain respect, or if they are simply the same as the same only in a certain respect, they should not be simply the same as each other. But the divine persons are simply and altogether the same as the divine essence, which essence is in itself altogether and simply the same;     therefore etc     . The major is plain because every syllogistic form, and this the form of the perfect syllogism [Aristotle, Posterior Analytics 1.4.25b32-35], holds on the basis of it; it is of itself evident, because in the premises the extreme terms are known to be conjoined in the middle term, and from this alone is concluded the identity of the extremes with each other in the conclusion; also because the opposite of the predicate destroys the subject, because if they are not the same as each other they are not simply the same as a third. The minor too is plain, because the essence itself is simply the same, for it is whatever it has, because of its supreme simplicity, according to the Master of the Sentences I d.8 ch.8, and Augustine City of God XI ch.10 n.1.

192. Again, essential and accidental divide the whole of being. So whatever is in something is the same as it either essentially or accidentally. But what distinguishes persons is not an accident of the essence (because nothing is an accident of itself), therefore it is essential; therefore it is the same as it essentially. But when what is essentially the same as the essence is multiplied the essence is multiplied; therefore if there are several persons there are several essences.

193. Again, nothing is to be posited in beings - and especially not in the highest good - such that when it is not posited nothing of perfection is lacking to the universe; but if some divine person does not exist in the divine essence, nothing of perfection is lacking to the universe; therefore a plurality of such things is not to be posited in God. Proof of the minor: if the second person did not exist, whatever perfection is posited in it would exist in the first person; also, no perfection would be lacking to the universe if the second person did not exist, because whatever of perfection exists simply in one person exists also in another. Therefore when one person is removed and another remains, nothing of perfection is taken from the universe.

194. You say it is not the case under every mode that ‘whatever of perfection is in one is also in another’.

On the contrary, that mode of having or of being is either a perfection or not a perfection. If it is it will exist in God, and consequently the first person, which will not have that mode, will not be simply perfect. If it is not then the argument stands that, when the second person does not exist, the whole of its perfection exists in the first; therefore nothing of perfection will perish from the universe when the second person is removed.

195. Again, that there be several necessary beings includes a contradiction, because if there are several necessary beings I ask by what are they formally distinguished? Let these be a and b. Either then those reasons by which they are distinguished are necessary beings and necessities of being, and then there will be two necessary beings; also they agree in necessary being and consequently they are not distinguished by necessary being. Or if those reasons are possible, then the things distinguished by them are not necessary beings [n.177].

196. To the opposite:

That is possible which does not include a contradiction. But there is no contradiction included in there being one essence in three persons, because contradiction is in the same respect. But here there is no contradiction in the same respect, because here there is unity of essence and plurality of relative supposits,     therefore etc     .