regular course of evolution. It is taken up by apostles who propagate it in a small circle, and it begins to spread. It at first meets with strong opposition, for it strikes forcibly against many ancient and established things. The apostles who have adopted it are excited by this opposition, which only persuades them of their superiority over the rest of men, and they defend it with energy, not, indeed, because it is true—for they generally know nothing about that—but simply because they have adopted it. The new idea is discussed and is accepted in whole by some and rejected in whole by others. Affirmations and negations are exchanged, but very few arguments; the only motives for the reception or rejection of an idea being, for the immense majority of minds, simply those of feeling, in which reasoning has no part. In consequence of these passionate contestations the idea progresses slowly. The young people who become aware of the contest adopt the idea readily, for the single reason that it is contested. To youth, eager to be independent, wholesale opposition to things that are accepted is the most easily accessible form of originality. The idea therefore continues to gain. As it is gradually accepted by official men of science it at length becames propagated wholly by the mechanism of contagion, and insinuates itself, timidly at first, and then boldly, into the classical books. Its triumph is then complete. Like religious dogmas, it becomes a part of the things that are not disputed. We have only to recollect the history of transformism in Trance, and how the scandalous heresy has passed into the state of a classic dogma, to observe the successive series of these phases of propagation.
After having prevailed for a considerable length of time the idea begins to lose its hold and at last dies out. But before an old idea is wholly destroyed it has to go through a series of retrogressive transformations that require many generations for their accomplishment. Before vanishing forever it takes its turn in forming a part of the old hereditary ideas which we qualify as prejudices, but respect nevertheless. The old idea, although it is already nothing but a word, a sound, a mirage, possesses a magical power that still subjects us. At last it dies. After reigning long over a civilization ideas lose their prestige, fade away, and are extinguished. New discoveries disturb them. Belief in them becomes less general. Men begin to discuss them, and by the mere fact of discussion their death is near. Every great directing idea being generally a fiction, they can not submit to be discussed except on condition of never being subjected to critical examination. But even when an idea has been violently disturbed the institutions derived from it retain their vitality and are effaced very gradually. When it has completely lost its
