Appendix 22. - (280)

The high esteem in which I hold Leibniz is the reason I am so hard upon him. Every careless turn in his argument deserves to be pointed out so that we may see how the slightest inattention leads to error. And error, however slight and scarcely perceptible it may be, always produces greater errors. This is especially the case with more logical and nimble minds.

Here, Leibniz, after stating that naked faculties are a mere abstraction, appeals to fact and claims that in the whole universe there is not a single dormant potency, that is, a potency which remains without an act, and in a state of naked, pure potency. This passage is wildly astray. He was speaking of the nature of potencies considered in themselves, and asserted that their nature was such that they were always associated with an act. In other words, he was speculating metaphysically whether a potency totally shorn of act was possible. We were in the realm of possibilities. Now, to prove it is impossible, he resorts to reality by asking: 'Where in the universe will we find a potency devoid of act?' But this means abandoning his first argument to relapse into the realm of reality; he appeals to experience to prove what is and is not possible. Experience, however, only witnesses to what is and what is not; it indicates facts alone. Consequently, it is useless in determining what is possible. Even if it could do this, it would be impossible to truly affirm or deny by means of observation the non-existence in the whole universe of a pure potency which does not, for at least a single moment, abide in this state of pure potency - if such a thing is possible. It is impossible to investigate them all, or submit them all to observation at every moment of their existence. Observations of this kind would enable us at most to induce a conjectural argument from analogy to prove a general, but still not absolutely necessary, fact. Leibniz frequently confuses the two worlds, the real and the possible.

Because such confusion has important consequences for this thinking, I hope I shall be forgiven if I mention another passage where the same association of fact and possibility can be noted, and where fact is called upon to prove possibility. In one passage he states:

Immediately after, he adds:

The first of these two propositions is abstract, but the second, dealing with bodies, becomes concrete and consequently not a necessary proposition like the first. If he had merely stated that bodies have to act because they are substances, and proved that they were substances and that every substance had to act, all would have been proved. But to say that all bodies move, and to add, 'Experience is on my side, and we only need to consult Boyle's famous book against absolute rest to be convinced' (ibid.), is to resort to what occurs in the real world in order to ascertain the stable, eternal relationships of the ideal world.

This becomes obvious on the occasions when Leibniz is guilty of arguing in a vicious circle. Thus, to prove that the understanding always thinks, he resorts to the need for each potency to have an act of its own - he resorts to fact. Experience does indeed show no examples in nature of potencies without action, but Leibniz' question, 'Does the intellect always think?' posited in this way is truly the question about the possibility of a potency totally shorn of its act.

Later, we shall see why Leibnz did not distinguish sufficiently between the ideal and the real world. We shall see that the very nature of his philosophy prevented his affirmation of such an important distinction.