Had there not at all times been a larger number of men who regarded the cultivation of their mind their "rationality " as their pride, their obligation, their virtue, and were injured or shamed by all fantasies and extravagance of thinking as lovers of " sound common sense " : mankind would long ago have perished! Incipient insanity has hovered, and hovers continually over mankind as its greatest danger : it is precisely the breaking out of inclination in feeling, seeing, and hearing ; the enjoyment of the unruliness of the mind ; the delight in human unreason. It is not truth and certainty that is the opposite of the world of the insane, but the universality and obligation of a belief, in short, the non-arbitrary character of judgements and opinions. And the greatest labour of human beings hitherto has been to agree with one another regarding a number of things, and to impose upon themselves a law of agreement regardless of whether these things are true or false. This is the discipline of the mind which has preserved mankind ; but the counter impulses are still so powerful that one can really speak of the future of mankind with little confidence. The ideas of things still continually shift and move, and will perhaps alter more than ever in the future ; it is continually the most select spirits themselves who strive against universal obligatoriness - the investigators of truth above all! The accepted belief, as the belief of all the world, continually engenders a disgust and a new longing in the more ingenious minds ; and already the slow tempo which it demands for all intellectual processes (the imitation of the tortoise, which is here recognised as the rule) makes the artists and poets runaways : it is in these impatient spirits that a downright delight in delirium breaks out, because delirium has such a joyful tempo! Virtuous intellects, therefore, are needed ah! I want to use the least ambiguous word, virtuous stupidity is needed, imperturbable conductors of the slow spirits are needed, in order that the faithful of the great collective belief may remain with one another and dance their dance further. It is a necessity of the first importance that demands this. We others are the exceptions and the danger - and we need eternally to be protected! Well, there is actually something to be said in favour of the exception, provided that it never wants to become the rule.