I know, certainly, that not only Spinoza and Hegel but even Kant would never have admitted that reason could refuse to guide man. "Reason avidly seeks universal and necessary judgments," says Kant at the beginning of his Critique of Pure Reason (First Edition). And not once in the course of his work does he ask himself: Why must we exert ourselves to furnish reason what it so avidly seeks? And who or what is this reason that possesses so great a power over man? Moreover, the fact that reason is possessed by a passion like every limited being should already suffice to put us on the alert and render reason and the universal and necessary judgments to which it aspires suspect in our eyes. But, I repeat, reason remains above all suspicion, even for the author of the Critique of Pure Reason.
Such has always been the tradition of human thought: distrust of reason has always been considered a crime of laesio majestatis. Plato said that the greatest misfortune that could come to a man was to become a "hater of reason." For Aristotle, knowledge is universal and necessary knowledge (katholou gar hai epistêmai pantôn, ex anankês ara estin to epistêton). From Socrates on, we have once and for all renounced what constitutes the essential problem of knowledge and, at the same time, the metaphysical problem. The aim of the Socratic thought was precisely to protect knowledge from every attempt at criticism, as appears in that statement which at first glance appears precisely the condition and the beginning of all criticism — "I know that I know nothing" (a statement which, according to Socrates' own testimony, made the oracle declare him the wisest of all men) — but which actually kills in the germ the very possibility of all criticism. Indeed only he who is convinced that knowledge is the sole source of truth will say he knows that he knows nothing. Not for nothing did Hegel, in connection with Socrates' fate, recall the tree of knowledge and the words of the tempting serpent, "You shall be like God." Only he who has tasted the fruits of the tree of the knowledge of good and of evil is capable of handing himself over so unreservedly to the enchantments of knowledge. For Socrates, to despise knowledge was a mortal sin. He reproached the poets, mocking them for seeking to attain truth by ways other than those of knowledge. And he could not find words harsh enough for those who, knowing nothing, believed that they did know something. Whence comes this unshakable assurance that knowledge alone brings man the truth? And what does this assurance that we have all inherited from Socrates mean? Did the oracle seduce Socrates as the biblical serpent had once seduced Adam? Or did the seduction lie elsewhere, and did Pythia, like Eve, only offer Socrates the fruit that she had herself tasted at the suggestion of a power that escapes our sharpest notice?
However this may be, after Socrates the most noted representatives of human thought could not do other than identify truth with the fruits of the tree of knowledge. This is the meaning of Plato's warning against the "hater of reason." This is the meaning of Aristotle's "in general (katholou) and "of necessity" (exanankês), of Descartes' "everything is to be doubted" and "I think, therefore I am," of Spinoza's "the true is the index of itself and of the false." This is why Kant declares at the beginning of his critique" that reason avidly seeks universal and necessary judgments.
All this constitutes the heritage of Socrates. Since Socrates the truth, for men, has been confounded with universal and necessary judgments. Everyone is convinced that thought has the right to stop only when it has come up against Necessity, which puts an end to all searchings and all curiosity. And at the same time no one doubts that thought, in penetrating to the necessary relationships of things, accomplishes the supreme task of philosophy. So that Hegel, in short, saw quite rightly when he sought to demonstrate that there are not "philosophies" but "philosophy," that all the philosophers have always understood in the same way the mission that fate had imposed upon them. All of them sought to discover the rigorous and unchangeable order of being, for all of them — even those who, like Socrates, knew that they knew nothing — were completely hypnotized by the idea that this order which depends on no one must exist, that it is impossible that it should not exist, just as there must exist a science which reveals this order to man.
Socrates said, it is true, that perfect knowledge belongs only to the gods and that the knowledge of man is incomplete. But in saying this he exalted knowledge still higher, for his words meant, in short, that the freedom of the gods was no longer absolute: knowledge sets limits to them by fixing the bounds not only of the possible and the impossible but even of the permitted and the forbidden. In the Euthyphro, written by Plato while his master was still alive, Socrates demonstrates that it is not given even to the gods to choose: they are not free not to love the just, as mortals are not free not to love it. Mortals and immortals are equally subject to duty and to Necessity. This is why the task of philosophy consists of revealing the necessary relationships of things, that is to say, in obtaining knowledge, in order to convince men that one cannot argue with Necessity, that one must obey it. Of course, the exact sciences also establish the necessary relationships of things and teach men obedience, but philosophy is not content with this. It is not enough for philosophy that men accept Necessity and accommodate themselves to it; philosophy wishes to bring it about that men should love and venerate Necessity, as they once loved and venerated the gods.
It may be that the essential difference between Socrates and the Sophists, a difference which history has carefully hidden from us, consists precisely in the fact that, when the Greeks of the second half of the Fifth Century discovered that the Olympian gods were the work of the imagination and that "constraints" of every kind came not from living beings who took the fate of men to heart but from Necessity which is indifferent to everything, the Sophists (as St. Paul was later to do) reacted violently: if constraints come not from the gods but from Necessity, then nothing is true, everything is permitted. Protagoras' "man is the measure of all things" has the same meaning, it seems, as St. Paul's phrase, "if the dead rise not, let us eat and drink";  in short, let us do whatever occurs to us, let us live just as we wish. No more than the Sophists did Socrates admit the existence of the gods. And this is quite understandable: he who is afraid of becoming a "hater of reason," who sees in knowledge the sole source of truth, cannot agree to recognize the gods. With a naïveté perhaps very alluring but hardly appropriate to a philosopher who wished to prove everything and to question everything, Socrates turned away disdainfully from the poets and the artists only because, even if they happen at times to discover high truths, they do not obtain these from knowledge but from some other source and are incapable of explaining how they have found them. Socrates had no confidence in men "inspired by the gods": how can one place confidence in them when it is known that the gods do not exist? Or — if Hegel's later commentary is admitted — when one knows that God deceived man, as He Himself admitted when the serpent, having penetrated His secret intentions, revealed them to our primal forefathers? In any case, if one wishes to be prudent, it is better to hold on to Protagoras: "As for the gods, I do not know whether they exist or whether they do not exist."
Before his judges, who had to pronounce judgment concerning the accusation of atheism brought against him by Anytus and Meletus, Socrates said in short the same thing as did Protagoras; but, since he spoke of the immortality of the soul and not of the existence of the gods, many people even today believe that Socrates thought otherwise than Protagoras. In reality, both of them set out from the same idea but reacted differently to it, though with the same passion. Protagoras said: if the gods do not exist, if the soul is not immortal, if human life is no more than this brief terrestrial existence which begins with birth and ends with death, if we are not bound by invisible threads to superior beings — in short, if everything that begins in the world also ends there — then what is it that can bind man's caprice and in the name of what shall man renounce his caprice? Why, in this case, should not man give free rein to his desires and passions? He is at times obliged to submit to force, insofar as he cannot conquer or escape it by any ruse. But to submit to it still does not mean to recognize its supreme and final rights. Let us — to speak as did St. Paul — eat, drink and rejoice.
Socrates' attitude in regard to the truth that he had discovered is completely different. Like Protagoras, he does not doubt for a moment that it is for reason to decide the question of the gods' existence; and, with the intellectual honesty that characterized him and in which he saw (and we also after him) the highest virtue of the philosopher, he had to recognize that in the sight of reason one could as well admit the existence of the gods and the immortality of the soul as deny them. Furthermore — Socrates did not say this but it may be believed that he thought it — since science is incapable of providing a positive answer to these questions, since a scrupulous examination leads him as well as Protagoras (so different from him in all respects) to the same conclusion — it may be that the gods exist or it may be that they do not exist — then the cause of the gods is in a bad way: there is every reason to believe that they were invented by men. Yet, the solution proposed by Protagoras was unacceptable to Socrates, just as he would have indignantly rejected the words of St. Paul if he had been able to know them. Anything was better in Socrates' eyes than Protagoras' homo-mensura or the apostle's "let us eat and drink." What remains to be measured by man if everything that is measurable is transitory and subject to change? And how can one think of rejoicing when he knows that his days are numbered and that no one is certain of tomorrow?
Long before Socrates the great philosophers and poets of Greece considered with terror the agonizing uncertainty of our transient and sorrowful existence. Heraclitus taught that everything passes, that nothing remains. With a power that has never been surpassed the tragedians portrayed the horror of human life. And yet, as if across the centuries he were echoing the prophet Isaiah and St. Paul who repeated Isaiah, Heraclitus could still say that what the gods have prepared for us surpasses all the dreams and hopes of men. But it was no longer given to Socrates to speak thus. We do not know what awaits us after death: is it not then shameful to speak of what one does not know? Heraclitus, Isaiah and St. Paul were as unacceptable to Socrates, enthralled by knowledge, as was Protagoras who glorified the arbitrary. It is obvious that the men of the Bible and the philosophers of Heraclitus' type drew their wisdom from sources extremely doubtful; they were like the poets who, in a burst of unjustified enthusiasm, proclaimed things that they themselves did not understand. Without knowledge there can be neither truth nor goodness. Consequently, knowledge is the only source of everything that is important to man; it gives man, and cannot do otherwise, the "one thing necessary." To be sure, if knowledge revealed to us the gods and the immortality of the soul, this would not be at all bad; but since it is otherwise, we shall have to get along without these. So it was that Socrates understood the task that devolved on him. He saw quite as well as Aristotle that a man of knowledge could be wicked. But he had discovered that our existence ends in death. Since this is so, the biblical serpent and Pythia were right: virtue resides only in knowledge. In the eyes of all, publicly, Socrates had to repeat the act which, according to the ancient myth that no one can attest, Adam had committed.
 1 Corinthians, 15, 32.