Disputationes metaphysicae

1. Hitherto we have only declared the notion of one and its various modes; but since this whole disputation tends to this, that we show that this attribute belongs to being, two things remain to be done. First, that we declare how this property is convertible with being and is its adequate attribute. Secondly, that we declare to which unity this belongs, which we shall do in the following section.

2. Concerning the first, the reason for doubting is that being is divided by one and many, as is evident from Aristotle, Metaphysics X, c. 1, and from St. Thomas, I, q. 11; indeed many contend that this is the first division of being, as Soncinas at length, Metaphysics X, q. 1; but a dividing member cannot be convertible with the thing divided; therefore neither one with being; therefore it is not its attribute. And it is confirmed; for one and many are opposed, on the testimony of Aristotle above; therefore they cannot belong to the same thing; therefore being which is many is not one; therefore one is not an adequate attribute of being.

3. In this doubt it must briefly be said that unity or one is an adequate attribute of being. So it is taken from Aristotle, Metaphysics IV, c. 2, text 3, saying that being and one follow each other mutually. Plato taught the same in the Parmenides, saying: Neither is being lacking to one, nor one to being, but these two rather are made equal throughout all things. The same St. Thomas, I, q. 11, aa. 1 and 2, and all philosophers. And it is evident by reason, first, because among the attributes of being one is placed in the first place, as we saw above; therefore it is necessary that it be convertible with being, because it is of the notion of an attribute properly so called that it be adequate to its subject; and therefore one is placed among the transcendentals, as being itself is. Secondly it is declared from the thing itself, because true and real unity supposes or includes entity, as was seen above; for what is nothing cannot be called one except equivocally and by extrinsic denomination; but upon every entity as it is entity indivision in itself follows or is necessarily conjoined; for if it is actually divided, as such it is not entity but entities; therefore the notion of one runs adequately with being. Thirdly, because every being is simple or composite; the simple is not only undivided but indivisible, in so far as it is simple; but the composite too, as it is such, is undivided; for if it is actually divided, it will not be composite. Therefore every being, both simple and composite, is one; but what is neither simple nor composite is not being; but will be either nothing, or several beings.

The division of being into one and many is explained

4. To the reason for doubting posited, then, St. Thomas answers, I, q. 11, a. 1, ad 2, that that which is undivided in one way can be divided in another, and that what under one notion is many can under another be one: And by this reason (he says) being is divided by one and many, as by one simply and many in a certain respect; for multitude itself too would not be contained under being unless it were contained in some way under one. And he adduces Dionysius, last chapter of On the Divine Names, saying that there is no multitude which does not participate in some way in unity; for things which are many in their parts are one in the whole; and things which are many in accidents are one in subject, etc. From which answer it is understood, first, that, formally and properly speaking, being is not divided into many as they are actually and formally many, because many of this kind, in so far as they are such, are in truth not being, but beings.

5. In two ways, then, multitude can be placed in the division of being: first, if it is understood not of actual multitude, that is, actually divided, which alone is properly multitude, as is evident from Metaphysics V, c. 13, text 18, but of multitude only in potency, in which way in the continuum there is said to be a multitude of integrating parts or of points, and in human nature a multitude of essential parts. And in this way St. Thomas seems to have understood the division, when he says that being is divided by one and many as by one simply and many in a certain respect; for that is one simply in which there are not many actually divided; and conversely those are called many in a certain respect which in the thing are not actually divided or disjoined, but only in potency. Whence in this sense these members, speaking per se, need not be distinguished in the thing, but in reason only; for the same being which is one simply is many in a certain respect or in potency, as is evident in the examples posited; unless we wish to understand those members with prescission or exclusion, in this way, that some being is so one that it is in no way many, neither in act nor in potency; but another is so one that it is also many in a certain respect or in potency or accidentally; in which sense that division will coincide with the division of being or of one into simple and composite. And according to this mode of interpreting it is easily evident that this division in no way stands in the way of the adequation of being and one; for that multitude does not exclude unity simply. Finally, in this sense it can be understood that in that division being is divided not as it is common to being per se and per accidens, but being per se itself, because among beings per se there are some which, although they are one in act, can nevertheless be many in potency.

6. In another way, however, that division can be expounded of multitude simply and properly, in which way Cajetan seems to have understood it when he says that those words of St. Thomas, in the said solution ad 2, being is divided by one and many, as by one simply and many in a certain respect, are to be so understood that simply and in a certain respect fall not upon one and many, but upon the verb is divided, that is, being is divided by one and many in such a way that one is being simply, but many in a certain respect. And in this way conversely it must be said that multitude is placed in the division of being in so far as it happens that things which are many simply are one in a certain respect. Whence the other member is understood of one simply and absolutely; and in this sense those members are always distinguished not by reason only but in the thing itself, because they include contradictory or privative opposition on the side of division; for those things are many simply which are actually divided in themselves; but that is one which is not actually divided in itself. And according to this sense too this division coincides with that by which being is divided into one simply and one in a certain respect; for many simply do not divide being except in so far as they are one in a certain respect. Whence it also comes about that the thing divided in this division so explained is not being per se, but that which is divided into being per se and per accidens; for every being per se is one simply; but many are not called one in a certain respect except in so far as they constitute some being per accidens, and so they cannot be placed in the division of being except at least under the notion of being per accidens; therefore the thing divided in that division cannot be being per se; for it would be repugnant to one member that it be convertible with the other; it must therefore be being abstracting from per se and per accidens. And so it is finally understood how the aforesaid division is not repugnant to the adequation of one and being; for it pertains to it that each thing be one as it is being, so that, if it is being per se, it is also one per se; but if it is being per accidens, it is also one per accidens; and as being can be signified abstractly, so also one; and therefore, as being in this sense is divided into one and many, so one itself too could be divided in the same way; for, as I said, it is the same as if it were divided into one simply and one in a certain respect.