Let us stop and ask ourselves: why does the truth that constrains need men's blessing? Why does Aristotle put himself to so much trouble to obtain for his Necessity men's blessing? Can it not get along without this blessing? If Necessity does not listen to reason, is it more receptive to praises? There is no doubt that constraining Necessity listens no more to praises than to prayers or curses. The stones of the desert have never replied "Amen" to the inspired sermons of the saints. But this is not necessary. What is necessary is that to the silence of the stones - is not Necessity, like the stones, indifferent to everything? - the saints should sing hosannas.
I would recall in this connection the chapters already mentioned of the Metaphysics and Ethics of Aristotle, the high priest of the visible and the invisible church of "thinking" men. We are asked not only to submit to Necessity but to adore it: such always has been, and such is still, the fundamental task of philosophy. It is not enough that philosophy should recognize the force and power, in fact, of such or such an order of things. It knows and it fears (the beginning of all knowledge is fear) that empirical force, that is, the force that manifests itself in constraining man only once, may be replaced by another force that will act in a different way. Even the scientist, who refuses to philosophize, has, finally, no need of facts; the facts by themselves give us nothing and tell us nothing. There has never been a genuine empiricism among men of science, as there has never been a genuine materialism. What scientist would study facts merely for the sake of facts? Who would wish to observe this drop of water suspended from a telegraphic wire, or this other drop that glides over the window-pane after a rain? There are millions of such drops and these, in and of themselves, have never concerned the scientists and could not concern them. The scientist wishes to know what a water-drop in general is or what water in general is. If, in his laboratory, he decomposes into its constituent elements some water drawn from a brook, it is not in order to study and know what he has at this moment in his hands and under his eyes but in order to acquire the right to make judgments about all the water that he will ever have occasion to see or never will see, about that which no one has ever seen and no one ever will see, about even that which existed when there was not a single conscious being or even any living being on earth. The man of science, whether he knows it or not (most often, obviously, he does know it), whether he wishes it or not (ordinarily he does not wish it), cannot help but be a realist in the medieval sense of the term. He is distinguished from the philosopher only by the fact that the philosopher must, in addition, explain and justify the realism practiced by science. In a general way, since empiricism is only an unsuccessful attempt at philosophical justification of the scientific, i.e., realistic, methods of seeking the truth, its work has, in fact, always led to the destruction of the principles on which it was based. It is necessary to choose: if you wish to be an empiricist, you must abandon the hope of founding scientific knowledge on a solid and certain basis; if you wish to have a solidly established science, you must place it under the protection of the idea of Necessity and, in addition, recognize this idea as primordial, original, having no beginning and consequently no end - that is to say, you must endow it with the superiorities and qualities that men generally accord to the Supreme Being. As we have seen, that is what was done by Aristotle, who thus deserves to be the consecrated pope or high priest of all men who think scientifically.
Doubtless Kant did not exaggerate Hume's merits when he wrote in his Prolegomena that since the beginning of philosophy no one had ever discovered a truth equal in importance to that which Hume discovered. As if scales had suddenly dropped from his eyes, Hume saw that the "necessary" bonds established by men between phenomena are only relationships of fact, that there is no "necessity" in the world, and that those who speak of necessity only "dream of being" but cannot see it in waking reality. Hume was too balanced a man - and one, moreover, who valued his equilibrium more than anything else in the world - to be able to appreciate and utilize the great discovery that he had made. One may, if one wishes, say as much of all those men whose eyes have been opened and who have been permitted to see extraordinary things; the sun of truth blinds the inhabitants of the kingdom of darkness with its brilliance. Hume ended up by restoring to Necessity almost all its sovereign rights; but Kant, not being able to bear the "almost" that no one had noticed, accomplished his Copernican task and directed our thought anew into that "sure and royal way" which mathematics had followed for centuries.
Hume's sudden discovery had awakened Kant from his dogmatic slumber. But is it given to men to be awake on earth? And is "nature that does not sleep,"  to use Plotinus' term, man's natural state? On the other hand, does not "to dream in sleep or while awake mean to take that which resembles (reality) not for something that resembles (reality) but for the reality that it resembles?"  Necessity resembles what really exists like two drops of water resemble each other, but it is not what really exists; it only seems really to exist for him who dreams. Hume's barely perceptible "almost" would have been able to render immense services to thinking and searching humanity if it had been preserved under the form in which it first appeared to the Scottish philosopher. But Hume himself was afraid of what he had seen and hastened to throw away everything that had fallen to his hand so as to have it no longer under his eyes. As for Kant, he found that this was still not enough and he transferred Hume's "almost" outside the limits of synthetic judgments a priori into the transcendental and noumenal - i.e., completely inaccessible, without relationship to us and without usefulness for us - world of things in themselves (Ding an sich). The shock that he had received from Hume awakened the great philosopher of Konigsberg from his sleep. But Kant understood his mission and destiny to mean that he must at all costs defend himself and others against the eventuality of sudden and brutal shocks that interrupt the peace of our somnolent waking, and he proceeded to create his "critical philosophy." At the same time as Hume's "almost," all metaphysics was transferred outside the limits of synthetic judgments a priori which, since Kant, have inherited all the rights of the old Necessity and have, for a century and a half, guaranteed to European humanity undisturbed sleep and faith in itself.
It is obvious that for Aristotle the most intolerable and distressing of thoughts was that our earthly life is not the last, definitive, truly real life and that an awakening, be it only in a certain measure, is possible - an awakening similar to that which we know in coming out of sleep. When he attacked Plato's "ideas" he was trying above all to rid himself of this eventuality which was, to him, worse than a nightmare. And his distress was, in a certain sense, completely justified, as was Kant's distress when Hume, with his "almost," so brutally awakened him from his dogmatic slumber. Plato's "they dream," quite like Hume's denial of any necessary bonds between phenomena, undermines the very foundations of human thought. Nothing is impossible. Anything that one wishes can flow from anything that one wishes and the principle of contradiction, which Aristotle wished to consider as "the most unshakable of principles," begins to totter, discovering to the frightened human mind the kingdom of the absolutely arbitrary which threatens to destroy the world and the thought which seeks to know the world; einai kai noein (being and thought) become phantoms. How could Plato have permitted himself to speak of his cave? How could he have imagined it? How could Hume have dared to deny the rights of Necessity? And does not humanity owe an eternal debt of gratitude to Aristotle and to Kant, to the first for having put an end, by his severe criticism and indignant cries, to the fantastic tendencies of his teacher, and to the second for having led our thought back into its natural groove by his doctrine of synthetic judgments a priori?
There cannot be two answers to these questions. Aristotle is the founder not only of the positive sciences but also of the positive philosophy. It is not for nothing that the Middle Ages saw in him the only guide through the labyrinth of life and did not dare to open the books, written without him (and perhaps also not for him), of the Old and New Testaments. The new philosophy has always followed, and still continues to follow, the paths that he marked out. One can say the same thing of Kant: he subdued the disquieting spirit of doubt and 'forced it to bow its rebellious head before the angelic visage of the universal and the necessary.
Necessity has obtained its justification - a justification of which it had no need at all. The celebrities of science, like all the ordinary scientists, glorify Necessity, even though it be as indifferent to blame as to praise. Only the wicked or the foolish can doubt its sovereign rights. But has this human defense rendered it stronger and more vigorous? Or should we not, perhaps, put the question differently: does not its force come from the fact that men have taken it under their protection and have surrounded it with an insurmountable wall made of formulas of incantation forged through the centuries?
 Enneads, II, 5, 3.
 Plato, Republic, 476C.