ligious, political, and moral ideas is determined very slowly. We should not, however, suppose that they are established and vanish with any extreme rapidity. Their evolution is indeed more rapid than that of other ideas, but it follows the same phases. Its history shows that although they address themselves only to the most enlightened minds, it takes them not less than twenty-five years, and usually much longer, to establish themselves. The clearest of them, the least hypothetical, those most easy to demonstrate, those which would seem least subject to controversy, like the doctrine of the circulation of the blood, have not been accepted in less time. In other respects scientific ideas are established under the influence of the factors we have described as acting with other ideas—affirmation, repetition, contagion, and prestige—and perhaps we may add, since we are dealing with the scientific category, reasoning; but the action of this factor is so weak that we might properly omit it. When it intervenes it is chiefly to refute an accepted idea, not to establish a new one. The new scientific idea is rarely imposed, so far at least as the majority of minds are concerned, by demonstration. It must not be supposed that because a man cultivates science he is released from the yoke of established dogmas. Scientific dogmas are often the most tyrannical of all.
The scientific idea is pre-eminently established by the prestige of the man who imposes it, and rarely in any other way. When Charcot introduced to science the phenomena of animal magnetism, which had been described for more than a century by students whose only fault was that they had no prestige, and whose admirable researches had been neglected for that reason by many generations of doctors, shall we suppose that the demonstrations of the professor were what convinced the medical public? Not at all, for the same demonstrations had been repeated thousands of times within a hundred years. The conviction was simply the result of the prestige of the expert, who did nothing but introduce into official science a series of phenomena which were perfectly known before him. After having been established by prestige the scientific idea goes through the
- It might be objected to this assertion that Darwin, who was without title, claim, or authority, had no prestige when he made his investigations. But it would be easy to answer, first, that his example is almost unique; and, second, that Darwin's doctrine was supported in England, as soon as it appeared, by men who had much prestige. I am, moreover, not sure that if Darwin had been born in one of the countries where mental worth is exclusively measured by the number of decorations it wears, the immortal book, the Origin of Species, would never have found a reader. The author would soon have been made to understand that, not being an academician or professor, he could only make himself ridiculous by taking up questions which had been long treated by the most illustrious specialists.