The development of truth in the human mind always proceeds slowly, and step by step. Even when the whole beginning and sure foundation is already found, or, rather, given, the inner evolution and external application of true science unfolds itself with extreme tardiness. At each point of progress much still remains to be overcome, much to be improved, and even to be thought upon once more, and reconsidered over and over again. Often, too, at the very last moment, an unexpected obstacle presents itself, or some new procrastination of a conscientious doubt or care.
Friedrich von Schlegel, Philosophy of Life, Morriston, tr., p. 534.