366. What is to be thought of the opinion according to which a man's various intellectual and moral faculties are the product of so many different spirits incarnated in him, and each possessing a special aptitude?
"The absurdity of such an opinion becomes evident on a moment's reflection. Each spirit is destined to possess all possible aptitudes; but, in order to progress, he must possess one sole and unitary will. If a man were an amalgam of different spirits, this unitary will would not exist, and he would possess no individuality, because, at his death, all the spirits would fly off in different directions, like birds escaped from a cage. Men often complain of not comprehending certain things, and yet how ingenious they are in multiplying difficulties, while they have within reach the simplest and most natural of explanations! Such an opinion is but another instance of the way in which men so often take the effect for the cause. It does for man what the pagans did for God. They believed in the existence of as many gods as there are phenomena in the universe; but, even among them, the more sensible ones only saw in those phenomena a variety of effects having for their cause one and the same God."
The physical and moral worlds offer us, in regard to this subject, numerous points of comparison. While the attention of mankind was confined to the appearance of natural phenomena, they believed in the existence of many kinds of matter. In the present day, it is seen that all those phenomena, however varied, may very probably be merely the result of modifications of a single elementary matter. The various faculties of a human being are manifestations of one and the same cause, which is the soul or spirit incarnated in him, and not of several souls just as the different sounds of an organ are the product of one and the same air, and not of as many sorts of air as there are sounds. According to the theory in question, when a man acquires or loses aptitudes or tendencies, such modifications would be the result of the coming or going of a corresponding number of the spirits conjoined with him, which would make of him a multiple being without individuality, and, consequently, without responsibility. This theory, moreover, is disproved by the numerous manifestations of spirits which conclusively demonstrate their personality and their identity.