There is no certainty, except when it is physically or morally impossible that the thing can be otherwise. What! is a strict demonstration necessary to enable us to assert that the surface of a sphere is equal to four times the area of its great circle; and is not one required to warrant taking away the life of a citizen by a disgraceful punishment?
If such is the misfortune of humanity that judges must be contented with extreme probabilities, they should at least consult the age, the rank, the conduct of the accused—the interest which he could have in committing the crime, and the interest of his enemies to destroy him. Every judge should say to himself: Will not posterity, will not entire Europe condemn my sentence? Shall I sleep tranquilly with my hands tainted with innocent blood? Let us pass from this horrible picture to other examples of a certainty which leads directly to error.
Why art thou loaded with chains, fanatical and unhappy Santon? Why hast thou added a large iron ring on thy miserable scourge? It is because I am certain of being one day placed in the first heaven, by the side of our great prophet. Alas, my friend, come with me to the neighborhood of Mount Athos and thou wilt see three thousand mendicants who are as certain that thou wilt go to the gulf which is under the narrow bridge, as that they will all go to the first heaven!
Stop, miserable Malabar widow, believe not the fool who persuades you that you shall be reunited to your husband in all the delights of another world, if you burn yourself on his funeral pile! No, I persist in burning myself because I am certain of living in felicity with my husband; my brahmin told me so.
Let us attend to less frightful certainties, and which have a little more appearance of truth. What is the age of your friend Christopher? Twenty-eight years. I have seen his marriage contract, and his baptismal register; I knew him in his infancy; he is twenty-eight—I am certain of it.
Scarcely have I heard the answer of this man, so sure of what he said, and of twenty others who confirmed the same thing, when I learn that for secret reasons, and by a singular circumstance the baptismal register of Christopher has been antedated. Those to whom I had spoken as yet know nothing of it, yet they have still the same certainty of that which is not.
If you had asked the whole earth before the time of Copernicus: has the sun risen? has it set to-day? all men would have answered: We are quite certain of it. They were certain and they were in error.
Witchcraft, divinations, and possessions were for a long time the most certain things in the world in the eyes of society. What an innumerable crowd of people who have seen all these fine things and who have been certain of them! At present this certainty is a little shaken.
A young man who is beginning to study geometry comes to me; he is only at the definition of triangles. Are you not certain, said I to him, that the three angles of a triangle are equal to two right angles? He answered that not only was he not certain of it, but that he had not the slightest idea of the proposition. I demonstrated it to him. He then became very certain of it, and will remain so all his life. This is a certainty very different from the others; they were only probabilities and these probabilities, when examined, have turned out errors, but mathematical certainty is immutable and eternal.
I exist, I think, I feel grief—is all that as certain as a geometrical truth? Yes, skeptical as I am, I avow it. Why? It is that these truths are proved by the same principle that it is impossible for a thing to exist and not exist at the same time. I cannot at the same time feel and not feel. A triangle cannot at the same time contain a hundred and eighty degrees, which are the sum of two right angles, and not contain them. The physical certainty of my existence, of my identity, is of the same value as mathematical certainty, although it is of a different kind.