Of course, this double reproduces all the essential traits of the perceptible being which serves it as external covering; but at the same time it is distinguished from this by many characteristics. It is more active, since it can cover vast distances in an instant. It is more malleable and plastic; for, to leave the body, it must pass out by its apertures, especially the mouth and nose. It is represented as made of matter, undoubtedly, but of a matter much more subtile and etherial than any which we know empirically. This double is the soul. In fact, it cannot be doubted that in numerous societies the soul has been conceived in the image of the body; it is believed that it reproduces even the accidental deformities such as those resulting from wounds or mutilations. Certain Australians, after having killed their enemy, cut off his right thumb, so that his soul, deprived of its thumb also, cannot throw a javelin and revenge itself. But while it resembles the body, it has, at the same time, something half spiritual about it. They say that "it is the finer or more aeriform part of the body," that "it has no flesh nor bone nor sinew"; that when one wishes to take hold of it, he feels nothing; that it is "like a purified body."[99]
Also, other facts of experience which affect the mind in the same way naturally group themselves around this fundamental fact taught by the dream: fainting, apoplexy, catalepsy, ecstasy, in a word, all cases of temporary insensibility. In fact, they all are explained very well by the hypothesis that the principle of life and feeling is able to leave the body momentarily. Also, it is natural that this principle should be confounded with the double, since the absence of the double during sleep daily has the effect of suspending thought and life. Thus diverse observations seem to agree mutually and to confirm the idea of the constitutional duality of man.[100]