The Divine Institutes

Does wisdom therefore nowhere exist? Yes, indeed, it was among them, but no one saw it. Some thought that all things could be known: these were manifestly not wise. Others thought that nothing could be known; nor indeed were these wise: the former, because they attributed too much to man; the latter, because they attributed too little. A limit was wanting to each on either side. Where, then, is wisdom? It consists in thinking neither that you know all things, which is the property of God; nor that you are ignorant of all things, which is the part of a beast. For it is something of a middle character which belongs to man, that is, knowledge united and combined with ignorance. Knowledge in us is from the soul, which has its origin from heaven; ignorance from the body, which is from the earth: whence we have something in common with God, and with the animal creation. Thus, since we are composed of these two elements, the one of which is endowed with light, the other with darkness, a part of knowledge is given to us, and a part of ignorance. Over this bridge, so to speak, we may pass without any danger of falling; for all those who have inclined to either side, either towards the left hand or the right, have fallen. But I will say how each part has erred. The Academics argued from obscure subjects, against the natural philosophers, that there was no knowledge; and satisfied with the examples of a few incomprehensible subjects, they embraced ignorance as though they had taken away the whole of knowledge, because they had taken it away in part. But natural philosophers, on the other hand, derived their argument from those things which are open, and inferred that all things could be known, and, satisfied with things which were manifest, retained knowledge; as if they had defended it altogether, because they had defended it in part. And thus neither the one saw what was clear, nor the others what was obscure; but each party, while they contended with the greatest ardour either to retain or to take away knowledge only, did not see that there would be placed in the middle that which might guide them to wisdom.

But Arcesilas, who teaches that there is no knowledge, when he was detracting from Zeno, the chief of the Stoics, that he might altogether overthrow philosophy on the authority of Socrates, undertook this opinion to affirm that nothing could be known. And thus he disproved the judgment of the philosophers, who had thought that the truth was drawn forth, and found out by their talents—namely, because that wisdom was mortal, and, having been instituted a few ages before, had now attained to its greatest increase, so that it was now necessarily growing old and perishing, the Academy suddenly arose, the old age, as it were, of philosophy, which might dispatch it now withering. And Arcesilas rightly saw that they are arrogant, or rather foolish, who imagine that the knowledge of the truth can be arrived at by conjecture. But no one can refute one speaking falsely, unless he who shall have previously known what is true; but Arcesilas, endeavouring to do this without a knowledge of the truth, introduced a kind of philosophy which we may call unstable or inconstant. For, that nothing may be known, it is necessary that something be known. For if you know nothing at all, the very knowledge that nothing can be known will be taken away. Therefore he who pronounces as a sentiment that nothing is known, professes, as it were, some conclusion already arrived at and known: therefore it is possible for something to be known.

Of a similar character to this is that which is accustomed to be proposed in the schools as an example of the kind of fallacy called asystaton; that some one had dreamt that he should not believe dreams. For if he did believe them, then it follows that he ought not to believe them. But if he did not believe them, then it follows that he ought to believe them. Thus, if nothing can be known, it is necessary that this fact must be known, that nothing is known. But if it is known that nothing can be known, the statement that nothing can be known must as a consequence be false. Thus there is introduced a tenet opposed to itself, and destructive of itself. But the evasive man wished to take away learning from the other philosophers, that he might conceal it at his home. For truly he is not for taking it from himself who affirms anything that he may take it from others: but he does not succeed; for it shows itself, and betrays its plunderer. How much more wisely and truly he would act, if he should make an exception, and say that the causes and systems of heavenly things only, or natural things, because they are hidden, cannot be known, for there is no one to teach them; and ought not to be inquired into, for they cannot be found out by inquiry! For if he had brought forward this exception, he would both have admonished the natural philosophers not to search into those things which exceeded the limit of human reflection; and would have freed himself from the ill-will arising from calumny, and would certainly have left us something to follow. But now, since he has drawn us back from following others, that we may not wish to know more than we are capable of knowing, he has no less drawn us back from himself also. For who would wish to labour lest he should know anything? Or to undertake learning of this kind that he may even lose ordinary knowledge? For if this learning exists, it must necessarily consist of knowledge; if it does not exist, who is so foolish as to think that that is worthy of being learned, in which either nothing is learned, or something is even unlearned? Wherefore, if all things cannot be known, as the natural philosophers thought, nor nothing, as the Academics taught, philosophy is altogether extinguished.