“Everyone by nature desires to know.” [Aristotle, Metaphysics I, I] To few has it been granted to know what to desire; to even fewer, to know. My own luck has been no different from that of others. From a young age I was led to the contemplation of nature; I inquired into all the minute details. And at first my mind, starving for knowledge, was satisfied with any food it could find. After some time, nevertheless, gripped by indigestion, it began to regurgitate everything. Even then I was trying to find something that would satisfy me completely and absolutely, but nothing could fulfill my desire. I read the sayings of prior generations, and put my contemporaries to the test; they gave the same response. Nevertheless, nothing was able to satisfy me. Some reflected a shadow of truth, but I found not even one who offered judgment of things sincerely and completely. So, I withdrew into myself; I called everything into doubt, and began to examine the things themselves as if no one had ever said anything about them - which is the true method of science. I broke everything down to first principles. Beginning my contemplation in this way, the more I thought, the more I doubted. I could understand nothing completely. I despaired. Nevertheless, I persisted. More, I went to the Doctors, hoping avidly to learn the truth from them. What then? Each construes his science partly out of the imaginings of others, partly out of his own. From these they infer other things, and then from those still others, without looking at the facts, producing a labyrinth of words without any basis in truth. In the end, you understand nothing of nature, but you learn new things, a fictional texture that no mind suffices to understand. For who could understand what doesn’t even exist? From this proceed Democritus’ atoms, Plato’s forms, Pythagoras’ numbers, and Aristotle’s universals, agent intellect, and intelligences…


I do not even know this one thing, that I know nothing. I nevertheless conjecture that neither I nor anyone else knows anything. Let this proposition be my banner, and come to be followed: Nothing is known. If I come to know how to prove this, I will be justified in concluding that nothing is known; if not, even more so; for I asserted just that. But you will say: If you know how to prove it, the contrary will follow, for you then know something. But I anticipated your objection and arrived at the opposite conclusion. I already begin to upset the matter: it already follows from this very thing that nothing is known. Perhaps you have not understood, and call me ignorant or a sophist. You have told the truth. But I can say the same of you even more so, for you have not understood. We are both ignorant. Therefore, you have unknowingly reached the conclusion I was seeking. If you have understood the ambiguity of the inference, you have seen clearly that nothing is known; if not, then think, draw some distinctions, and untangle this knot for me. Sharpen your wits. I am on your trail.


Let us reckon the thing by its name. For from my point of view every definition and every question is about names. I will explain. We cannot recognize the natures of things; I at least cannot. If you say you can, then fine; I won’t argue with you. Nevertheless, it is false, for why are you more capable than I? And hence we know nothing. If we do not comprehend, how can we demonstrate anything? We can’t. You nevertheless say that there is a definition that demonstrates the nature of the thing. Give me one. You don’t have one. I therefore draw my conclusion. Moreover, how can we give names to things we do not understand? I don’t see how. Nevertheless, there they are. Hence, surrounding names there is perpetual doubt, and there is much confusion and fallacy about words - even, maybe, in what I have just put forward.


Draw the conclusion. You say that you can define a thing, man - not just a word - with this definition: a mortal, rational animal. I deny it. For I in turn doubt the word animal and rational, and the rest. You will go on to define these in terms of higher genera and differentiae, as you call them, until you reach Being. I will ask the same question about each of these. Finally, the last, Being: for you know nothing about what it signifies. You cannot define it, for it has no higher genus, you will say. I don’t understand this. Neither do you. You don’t know what Being is. Even less do I. You will nonetheless say that questions should finally be put to rest. This neither resolves doubt nor satisfies the mind. You are forced to display your ignorance. I rejoice…


Listen. Prove that a man is a being. You say this: A man is a substance; a substance is a being; therefore a man is a being. I doubt the first and second premises. Say you argue for the first: A man is a body; a body is a substance; therefore a man is a substance. Again I doubt both premises. You say: A man is a living thing; a living thing is a body; so, a man is a body. I say the same. You argue: A man is an animal; an animal is a living thing; therefore a man is a living thing. Highest God! What a series, what a hodge-podge, all to prove that a man is a being! The answer is more obscure than the question…


We know nothing. Suppose that the explication of knowledge I have laid down is correct, for the purposes of discussion. From this let us infer that nothing is known. For to suppose is not to know but to pretend; that is why from suppositions we get fictions, not knowledge. See where the argument has led us: All knowledge is fiction. It is clear. Knowledge is obtained by demonstration. This presupposes a definition. Definitions cannot be proved; they must be believed. Therefore, a demonstration from what is supposed produces only supposed knowledge, not firm and certain knowledge. All these things follow from your own premises. As you say, first principles must be supposed in every field of knowledge, and these must not be disputed. Hence what follows from these will be supposed, not known. What could be more miserable? To know, we must be ignorant. For what is “supposing” but admitting that we do not know? Wouldn’t it be better to know the first principles? I deny your first principles: prove them. You don’t have to argue against people who deny your first principles? You don’t know how to prove them. You are ignorant, not knowledgeable. A higher or more general science can establish the first principles of other sciences? Maybe, then, the person who knows this higher and more general science has the knowledge, you don’t. For anyone who is ignorant of first principles is ignorant of the thing. What is that more general science, anyway?…


But aren’t these fables for children? For in a public place - a courtyard, a marketplace, a field - they construct little gardens, mark their boundaries with tiles, and prohibit others from entering their little spaces. I see what this is about. Since no one can embrace everything, each chooses a part for himself while others tear the rest to pieces. Hence nothing is known. For since all the things in the world constitute a single whole, some cannot exist without others; some cannot persist without others. Each fulfills its own function, different from the rest. But all contribute to the whole. Some cause others; some are caused by others. The concatenation of all of them is indescribably complex. It is therefore not surprising that, if we are ignorant of one, we are ignorant of the rest…”