"As soon as an opinion becomes common it is sufficient reason for men to abandon it and to uphold the opposite opinion until that in its turn grows old, and they require to distinguish themselves by other things. Thus if they attain their goal in some art or science, we must expect them soon to cast it aside to acquire some fresh fame, and this is partly the reason why the most splendid ages degenerate so quickly, and, scarcely emerged from barbarism, plunge into it again."