Chapter 8

Fourth special law: the term of thought is one

1357. Another property of an ens is that it is one. If it were not one, it would not be an ens. It is necessary therefore that one be always present in the object of thought; otherwise there would be no ens. An ens is always an individual and, without attributing an individuality to it, cannot be thought with entire, complex thought.

1358. What is the origin of the idea of one or unity? It is given with the idea of an ens and is obtained from the ens by means of abstraction.(180) Without an ens no idea is possible; with an ens the idea of one is immediately in the mind.

1359. This explains why the Scholastics said that one and ens are interchangeable.(181) The ancient philosophers, particularly the Pythagoreans, took 'one' to mean 'ens in the abstract', without determining anything else in it. But anything abstract is an incomplete ens, and many of the things they said about this kind of ens apply only to a complete ens. This mistake is the real source of the errors of the Pythagoreans.

1360. The Scholastics also said, 'Everything is one by its essence',(182) and asked, 'Can the mind understand several things simultaneously?' They replied in the affirmative but on condition that the mind thinks these things per modum unius [as one]; for the Scholastics, one must always be present in the object of thought.

1361. The first philosophers (who also influenced Plato) could not find unity in body because they looked for it in matter, that is, in body separate from the sentient principle and therefore divisible ad infinitum . Unable to arrive at a first, extended element possessing unity that could not be lost through further division, they denied that body was an ens and could be the object of knowledge. Thus they changed body into a phenomenon which they said people in general take for an ens but which philosophy sees as a mere phantom. In short these philosophers fell into idealism or, more correctly, posited the ontological principles from which platonic idealism originated. But I have placed the unity of body in its essential relationship with the sentient principle. I fully agree that the felt and sensiferous elements, when separated from this principle, can no longer be conceived. However I said that this necessary relationship of body with the sentient principle does not in any way deny its reality; it simply demonstrates that by nature body must be united to a sentient principle from which it receives perfect continuity and therefore the necessary unity for being an ens.(183)

1362. Because ens is one:

1.It is interiorly harmonious and concordant, and excludes all contradiction or repugnance. As I said, this makes it logically possible. Hence the principle of contradiction expresses simply the unity and concordance of ens with itself. This immunity of ens from all contradiction and intrinsic repugnance was seen by the ancient thinkers. Parmenides expressed it in the fragment preserved by Clement of Alexandria:(184) 'You will never sunder being from its hold on being.'(185)

2.It is simple in such a way that if it lacks anything constituting it as ens, it is no longer one. Parmenides saw this and expressed it in a fragment given by Theodoret: 'If something is lacking, all ens must be lacking.'(186) Precisely for this reason I induced the conditions and laws of thought from the principal properties of ens. But Parmenides did not see that something can be called 'ens in the course of formation' when separated from its essential relationships , as I explained when speaking about matter, etc.

3.It is immune from space and time by reason of its simplicity, and constitutes what I call the 'metaphysical world'. This also was seen by Parmenides and mentioned in the fragment recorded by Clement in his Stromata :(187) 'With your mind contemplate attentively what is absent as though it were present.'(188)

Notes

(180) NE, vol. 2, 575-578.

(181) St. Thomas, Quodl ., 6: 1; Aristotle, Metaph ., bk. 4: 2.

(182) St. Thomas, S.T. , I, q. 5, art. 3, ad 1. Is this principle true relative to the divine persons? I answer negatively, together with St. Thomas, who defines oneness as 'that which is undivided in itself and divided from other things'. In the divine persons there is no difference of essence that can divide one person from the other; each person has the same essence and nature. Hence the principle that distinguishes them is not essence but relative property . 'Personal unity is the RELATIVE PROPERTY which distinguishes one person from another, not the essence of the person himself' (In 1 Sent ., Dist ., 19, q. 4, art. 1, ad 1). — Nevertheless unity or one can be considered under two aspects: 1. what it is in itself (ens divisum [undivided ens]); 2. what it is relative to something else, that is, as a principle of division (divisum ab aliis [divided from other things]). If we consider unity as that which it is in itself, each person in the holy Trinity is one because the essence is one and most simple. But this unity and simplicity of person is not a principle of distinction from the other persons. The principle of distinction between them is purely the relative property , as I said. It is not absolutely true therefore that that which constitutes one, that is, a substantial ens, is that which distinguishes what is one in the substantial ens from some other one which is also in the substantial ens. The same substance subsists in the three, that is, in the three divine persons.

(183) Apparently Parmenides was aware of the part played by continuity of body. We can gather this from the attribute he requires for an ens to be such, that is, continuity (t¿ sunecŒv). Aristotle disagrees with Parmenides; he says the continuum is that which holds together by means of a continued series of parts and therefore can be divided ad infinitum (*). For Parmenides on the other hand, ens cannot have parts (Phys ., 1, 2; De caelo , 1, 1; Categor ., 6). But Aristotle is mistaken because the continuum is not in reality divisible but only limitable by human imagination . Strictly speaking, the continuum is immobile space, whether occupied or empty, as I have said.

(184) Strom ., 5, p. 652.

(185) (*).

(186) Theodoretus, Therapeut ., Serm. 1, p. 13.

(187) Clem. Alex., Strom ., 5, p. 552.

(188) (*)