This indefinable something, the professor considers, would never have appeared in the world without an impulsion, however light; an accidental movement, a casual combination of a disordered brain, and a personality endowed with a certain amount of energy, would have sufficed to make a single individual the author of an idea totally opposed to man’s good possession common sense, and the originator of a movement which must find in the surroundings in which it came to life, all facilities for its indefinite perpetuation. It is of no consequence whether this mental phenomenon has been produced in one individual or in more; figures are of little account in the matter. If this disease called hallucination[68] had remained confined in the circumscribed sphere of one individual or a few, a personal intelligent effort might have overcome it, but being contagious and spreading amongst the people it became impossible to conquer it. The natural laws of reason once violated, the perturbed mind created a succession of sophistical arguments which appeared to satisfy the ineradicable desire for happiness in man; and an incredibly tenacious opposition on the side of error assumed menacing proportions. If the belief that the sun, instead of disappearing each night below the horizon, would continue to shine during the night could in any way contribute to the happiness of mankind, men would slowly but surely have accepted it. The man who isolates himself from his fellow men and becomes self-absorbed is peculiarly apt to create for himself mental pictures which give him pleasure; if, then, joy is indispensable to man’s existence, the religion which gives it, or the illusion of it, enables him to forget the tangible world, and substitute an imaginary one peopled with phantoms. But the solitary man is a rare phenomenon, and we judge favourably those men who live in the midst of their social surroundings, and whose community of ideas and sentiments has made a homogeneous whole, during many centuries. Each one will find means to develop his personal faculties, and to strengthen his power of resistance in the struggle of all against all, and the good which is illusive in the solitary man becomes a benefit to the members of the society.