31. These examples show that philosophers take a very different road to certainty from that taught by nature. He who created all things out of nothing, has provided them with all that is necessary to the exercise of their functions according to their respective positions in the universe; and one of the first necessities of an intelligent being is the certainty of some truths. What would become of us, if before beginning to receive impressions, and before the germination of primary ideas in our understanding, we were obliged to perform the painful task of elaborating some system capable of saving us from uncertainty? Were it thus, our intellect would perish at its very birth, for no sooner would it open its eyes to the light than it would be involved in the chaos of its own cavils, and it could never, with its scattered forces, succeed in dissipating the clouds which would arise on all sides, and which would finally sink it in total darkness.
If the greatest philosophers, the most clear and acute intellects, the strongest and most vigorous geniuses have labored to so little purpose to establish solid principles, such as might serve for the foundations of science, what would have happened had not the Creator succored us in this necessity, and given certainty to the tender intellect, just as he prepared for the preservation of the body the milk that nourishes and the air that vivifies it?
32. If any part of science ought to be regarded as purely speculative, it is undoubtedly the part which concerns certainty; and this proposition, paradoxical as it may seem at first sight, is true, and can be easily demonstrated.
33. What does philosophy here propose to do? To produce certainty? But it exists independently of all philosophical systems, and mankind were certain of many things before ever any one thought of such questions. Moreover, since the question was first raised, few, compared with the whole human race, have examined it; so it is now, and so it will be; and all the theories invented on this point can have no effect upon the fact of certainty. What has been said of its production may be said of the attempt to consolidate it. When have the generality of men had, or when will they have, time and opportunity to examine these questions?
34. Philosophy could here have produced nothing but skepticism, for the variety and opposition of systems were more calculated to create than to dissipate doubts. Happily nature is the most invincible opponent of skepticism; the sage's dreams pass not from his library to the every day uses of the life of ordinary men, or even of those who labor under or imagine them.
35. Philosophy here can propose to itself no more reasonable object than simply to examine the foundations of certainty, with the sole view of more thoroughly knowing the human mind, not of making any change in practice; just as astronomers observe the course of the stars, investigate and determine the laws to which they are subject, without therefore presuming to be able to modify them.
36. But even this supposition places philosophy in a very unsatisfactory position; for if we recollect what we have already established, we shall see that science observes a real and true phenomenon, but gives it a gratuitous explanation, by making an imaginary analysis of it.
Experience has in fact shown our understanding to be guided by no one of the considerations made by philosophers; its assent, when it is accompanied by the greatest certainty, is a spontaneous product of a natural instinct, not of combinations; it is a firm adhesion exacted by the evidence of the truth, the power of the internal sense, or the impulse of instinct; not a conviction produced by a series of ratiocinations. These combinations and ratiocinations therefore exist only in the mind of philosophers, not in reality; when, therefore, they attempt to designate the foundations of certainty, we are told what could or should have been, but not what is.
If philosophers would only be guided by their own systems, and would not forget them nor set them aside as soon as, or even before, they have finished explaining them, it might be said, that even if no reason can be given for human certainty, one can be given for philosophical certainty; but since these same philosophers make no use of these scientific means save when developing them ex professo, it follows that their pretended foundations are a mere theory, having little or no connection with the reality.