Lamennais calls common sense the only criterion; nevertheless, we have only to glance at the others to be convinced that this new criterion is sterile, and could not produce them.
330. The testimony of consciousness, in the first place, cannot rest in any sense upon the authority of others. Formed as it is by a series of acts intimately present to our own mind, and, as without it, it is not possible for us even to conceive individual thought, it must evidently exist prior to the application of any criterion, since no criterion is possible to him who does not think.
Under a scientific aspect nothing can be weaker than his pretended refutation of Descartes' principle. "When, trying to rise from his methodical doubt, Descartes establishes this proposition, I think, therefore I am, he passes an immense abyss, and lays in the clouds the corner-stone of the edifice he is about to raise; for, strictly speaking, we cannot say I think, we cannot say I am, we cannot say therefore, or affirm anything as a consequence."[34]
Descartes' principle merited a more careful examination from whoever would invent a system. To oppose to it that we cannot say therefore, is to repeat the worn-out argument of the schools; and to affirm that we cannot say I think, is to contradict a fact of consciousness not denied even by skeptics. In place of this, we will explain at due length what is, or at least, what ought to be, the sense of Descartes' principle.
If, according to Lamennais, we cannot say I think, still less can we say that others think; and as his system recognizes one only criterion, common consent, which absolutely needs the thought of others, it follows that Lamennais has laid his corner-stone higher in the clouds than he who founded philosophy upon a fact of consciousness.
331. A criterion, especially when it pretends to be the only one, ought to have these two conditions: to apply to all cases, and not to suppose another. Now the criterion of common consent is precisely that which is farthest from possessing these conditions: prior to it is the testimony of consciousness; prior also to it is the testimony of the senses, for we cannot know the consent of others if sight or hearing do not make us certain of it.
332. In many cases this criterion is impossible; in many others it is exceedingly difficult if not wholly impossible. To what point is common consent needed? If the word common refers to the whole human race, how are the suffrages of all mankind to be recognized? If the consent need not be unanimous, to what point does the contradiction, or the simple non-assent of some, destroy the legitimacy of the criterion?
333. Lamennais' error consists in taking the effect for the cause, and the cause for the effect. We detect certain truths, upon which all men are agreed, and we say: the guaranty that each one is right is the consent of all. If we analyze this well, we shall perceive that the reason of each individual's certainty is not the consent of others; but on the contrary the reason why all agree is that each one for himself feels obliged to give his assent. In this universal voting of the human race, each one gives his own vote, impelled in a certain sense by nature herself; and as all experience the same impulse, all vote alike. Lamennais says every one votes in the same way, because all vote so; but he does not observe that then the voting could never begin nor end. This comparison is not an accidental satire, but a strictly philosophical argument, to which there can be no reply; it suffices to show the system of Lamennais to be unfounded and contradictory; just as, on the other hand, it indicates the origin of the equivocation, the taking the effect for the cause.
334. Lamennais, in order to prove his criterion to be the only one, appeals to the testimony of consciousness. In our opinion this testimony establishes directly the contrary. Who ever waited for the authority of others to be certain of the existence of bodies? Do we not see even brutes, by force of a natural impulse, making, in their own way, their sensations objective? Had we not in giving our assent to the words of men some other criterion than common consent, we could never believe any one, for the simple reason that it would be impossible to be certain of what others say or think without beginning by believing some one. Does the child refer to the authority of others before giving faith to what its mother recounts? Does it not rather obey the natural instinct communicated to it by the beneficent hand of the Creator? It does not believe because all believe; but all children believe because each one of them believes: their individual belief does not spring from a general belief, but rather the general belief is formed from the assemblage of individual beliefs; it is not natural because universal, but universal because natural.
335. Lamennais' chief argument consists in this: that in certain cases in order to make sure of the truth relatively to the other criteria, we appeal to that of common consent, and that folly itself is only the deviation from this consent. If you tell a man that his eyes deceive him as to an object which he sees, he instinctively turns to other men, and asks them if they do not see it in the same way. If all agree that he is wrong, and he is satisfied they are in earnest, he will experience a momentary vacillation of his faith in the testimony of sight; he will approach the object, will take a different position, or adopt whatever other means may seem to him best suited to make sure that he is right. If he still sees the object in the same way, and the same persons and others who arrive persist in assuring him that the thing is not as he sees it, he will distrust the testimony of sight, and believe himself subject to some infirmity affecting his sight. To this is the argument of Lamennais reduced. What results from it? Nothing to support the system of common consent. True, the other criteria are, in exceptional circumstances, liable to error; in certain cases when a doubt arises an appeal is taken to the testimony of others: but why? Simply, in order to make sure that one has not labored under one of those derangements to which human misery is subject. We know that what is natural is general; and he who doubts inquires of others, that he may ascertain if he has by some accident been out of his ordinary natural state. Who sees not the unreasonableness of raising an exceptional means to the rank of sole and general criterion? Who sees not the extravagance of asserting that we are assured of the testimony of the senses by the authority of other men, solely because, in extreme cases fearing some derangement of our organs, we ask others if something appears to them as it does to us?
336. Greater exaggeration we cannot have than that of Lamennais, when he affirms "that the exact sciences are also founded on common consent; that in this they enjoy no privilege, and that the very term exact, is one of those empty titles under which man seeks to conceal his weakness; that geometry itself only exists by virtue of a tacit convention, a convention which may be thus expressed: we are obliged to hold such principles to be certain, and we pronounce every one a rebel to common sense, that is, to the authority of the number, who shall demand a demonstration of them." This is an intolerable exaggeration. The arguments which he adduces in his notes to prove the intrinsic uncertainty of mathematics are exceedingly feeble; and some of them might make us suspect the author of the Essai sur l'Indifference to be a less profound philosopher than eloquent writer.
I am not ignorant of what has been advanced against the certainty of the exact sciences, nor of the difficulties they present when called before the tribunal of metaphysics. In the first volume of Protestantism compared with Catholicity, I consecrated a chapter to what I call instinct of faith; and this instinct, I there maintained, also exercises its influence upon the exact sciences. These I do not place above moral sciences; I esteem these latter the more; but I must avoid an exaggeration that would destroy them all.
CHAPTER XXXIV.
SUMMARY AND CONCLUSION.
337. In concluding this book, I wish to give a summary of my views on certainty, wherein I shall show the connection between the doctrines exposed in the different chapters.
When philosophy meets a necessary fact its duty is to accept it. Such a fact is certainty. To dispute its existence, is to dispute the splendor of the sun at mid-day. Mankind are certain of many things; philosophers, skeptics not excluded, are equally so. Absolute skepticism is impossible.
Setting aside the question of certainty, philosophy is free from extravagance, and is established in the domain of reason;