SECOND ARTICLE [I, Q. 11, Art. 2]

Whether "One" and "Many" Are Opposed to Each Other?

Objection 1: It seems that "one" and "many" are not mutually opposed.

For no opposite thing is predicated of its opposite. But every

_multitude_ is in a certain way _one,_ as appears from the preceding

article. Therefore "one" is not opposed to "multitude."

Obj. 2: Further, no opposite thing is constituted by its

opposite. But _multitude_ is constituted by _one._ Therefore it is not

opposed to "multitude."

Obj. 3: Further, "one" is opposed to "one." But the idea of "few"

is opposed to "many." Therefore "one" is not opposed to "many."

Obj. 4: Further, if "one" is opposed to "multitude," it is

opposed as the undivided is to the divided; and is thus opposed to it

as privation is to habit. But this appears to be incongruous; because

it would follow that "one" comes after "multitude," and is defined by

it; whereas, on the contrary, "multitude" is defined by "one." Hence

there would be a vicious circle in the definition; which is

inadmissible. Therefore "one" and "many" are not opposed.

_On the contrary,_ Things which are opposed in idea, are themselves

opposed to each other. But the idea of "one" consists in

indivisibility; and the idea of "multitude" contains division.

Therefore "one" and "many" are opposed to each other.

_I answer that,_ "One" is opposed to "many," but in various ways. The

_one_ which is the principle of number is opposed to _multitude_ which

is number, as the measure is to the thing measured. For "one" implies

the idea of a primary measure; and number is _multitude_ measured by

_one,_ as is clear from _Metaph._ x. But the _one_ which is convertible

with _being_ is opposed to _multitude_ by way of privation; as the

undivided is to the thing divided.

Reply Obj. 1: No privation entirely takes away the being of a thing,

inasmuch as privation means "negation in the subject," according to

the Philosopher (Categor. viii). Nevertheless every privation takes

away some being; and so in being, by reason of its universality, the

privation of being has its foundation in being; which is not the case

in privations of special forms, as of sight, or of whiteness and the

like. And what applies to being applies also to one and to good,

which are convertible with being, for the privation of good is

founded in some good; likewise the removal of unity is founded in

some one thing. Hence it happens that multitude is some one thing;

and evil is some good thing, and non-being is some kind of being.

Nevertheless, opposite is not predicated of opposite; forasmuch as

one is absolute, and the other is relative; for what is relative

being (as a potentiality) is non-being absolutely, i.e. actually; or

what is absolute being in the genus of substance is non-being

relatively as regards some accidental being. In the same way, what is

relatively good is absolutely bad, or vice versa; likewise what is

absolutely _one_ is relatively _many,_ and vice versa.

Reply Obj. 2: A _whole_ is twofold. In one sense it is homogeneous,

composed of like parts; in another sense it is heterogeneous,

composed of dissimilar parts. Now in every homogeneous whole, the

whole is made up of parts having the form of the whole; as, for

instance, every part of water is water; and such is the constitution

of a continuous thing made up of its parts. In every heterogeneous

whole, however, every part is wanting in the form belonging to the

whole; as, for instance, no part of a house is a house, nor is any

part of a man a man. Now multitude is such a kind of a whole.

Therefore inasmuch as its part has not the form of the multitude, the

latter is composed of unities, as a house is composed of not houses;

not, indeed, as if unities constituted multitude so far as they are

undivided, in which way they are opposed to multitude; but so far as

they have being, as also the parts of a house make up the house by

the fact that they are beings, not by the fact that they are not

houses.

Reply Obj. 3: "Many" is taken in two ways: absolutely, and in that

sense it is opposed to "one"; in another way as importing some kind

of excess, in which sense it is opposed to "few"; hence in the first

sense two are many but not in the second sense.

Reply Obj. 4: "One" is opposed to "many" privatively, inasmuch as the

idea of "many" involves division. Hence division must be prior to

unity, not absolutely in itself, but according to our way of

apprehension. For we apprehend simple things by compound things; and

hence we define a point to be, "what has no part," or "the beginning

of a line." "Multitude" also, in idea, follows on "one"; because we

do not understand divided things to convey the idea of multitude

except by the fact that we attribute unity to every part. Hence "one"

is placed in the definition of "multitude"; but "multitude" is not

placed in the definition of "one." But division comes to be

understood from the very negation of being: so what first comes to

mind is being; secondly, that this being is not that being, and thus

we apprehend division as a consequence; thirdly, comes the notion of

one; fourthly, the notion of multitude.

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Summa Theologica, Part I (Prima Pars) From the Complete American Edition · 第 81 / 722 题