It matters little whether the intelligence be, as Taine believed, a normal product of the brain, or a malady, especially as a blemish, transmitted as such from generation to generation, ends by losing its pathological characteristics. It becomes an integral and normal part of the organism.[2] Its accidental origin is, however, corroborated by this, that although an excellent instrument for a priori combinations, the intelligence is, one would say, especially unfitted for the perception of realities. It is to this infirmity that we owe metaphysics, religions and ethical systems. As the external world can reach the consciousness only by scrupulously conforming to all the nooks and crannies of the pocket, it turns out that, believing to hold an image of the world, we have only an image of ourselves. Certain rectifications are possible. Analysis of the phenomena of vision has made us admit that. By comparing our sensations and our ideas with what we can comprehend of the sensations and ideas of others, we arrive at a determination of probable averages; but, above all, negative averages. It would be easier to draw up a list of non-truths than a list of truths. To affirm that a given religion is false, no longer denotes great boldness of intellect or even much intellect. The veracity of any religion whatsoever is to-day a subject for controversy only for the various European clergies who make their living out of it, or for those belated rationalists who, like their master Kant, are ever awaiting the propitious and lucrative hour for opportune conversions. But, to the naïve question presented by those who, like nature, in the seventeenth century, abhor a vacuum:--"What will you put in its place?"--no answer can be made. It is enough, and it is no small thing at that, to have transmuted a truth into a non-truth. The higher calling of criticism is not even, as Pierre Bayle proclaimed, to sow doubts; it must destroy. The intelligence is an excellent instrument of negation. It is time to employ it, and so stop trying to rear palaces with picks and torches.
The history of the idea of immortality is a good example of our congenital inability to perceive realities otherwise than reshaped and worked over by the understanding. The idea of immortality is born of belief in the double. In sleep, and while the body is inert, there is a part of man that stirs, that travels, that fights, that eats, enjoys or suffers, exhibits all the phenomena of life. This part of man, this double of man, this astral body, survives the decomposition of the material body, whose habits and needs it keeps. Such, doubtless, is the origin of the belief in what, since Hellenism, we call the immortality of the soul. In an earlier stage, the Egyptian religion was based upon the theory of the double. It was for doubles, and not for souls, that first real, and later symbolic, food was placed in the tombs. But the Egyptian religion was already charged, in addition, with the idea of justice, of equilibrium. The doubles were weighed in the scales of good and evil. Ethical metaphysics had obscured the primitive idea of immortality, which is nothing but the idea of indefinite duration.