Let me recount an incident that, without any kind of adaptation from my side, comes straight from an insane asylum. A patient in such an institution wants to run away, and he actually succeeds in his plan by leaping through the window. Now finding himself in the institution’s garden, he is about to take to the road of freedom when the thought strikes him (should I say that he was sane or insane enough to hit on this idea?): ‘When you come to the town you will be recognized and presumably brought straight back, so what you need to do is completely convince everyone, through the objective truth of what you say, that the matter of your sanity is quite in order.’ As he walks along thinking about this, he sees a skittle bowl lying on the ground, picks it up and places it in his coat tail. Every step he takes, the bowl bangs his (to put it politely) ‘a – ’, and every time it bumps, he says, ‘Bang, the earth is round!’ He comes to the town and immediately calls on one of his friends. He wants to convince him that he is not crazy, and so he walks back and forth, saying repeatedly: ‘Bang, the earth is round!’ And indeed is not the earth round? Does the asylum crave yet another sacrifice for this opinion as when everyone believed it to be as flat as a pancake? Or is that man insane who hopes to prove that he is sane by uttering a universally accepted and respected objective truth? Yet, to the physician it was precisely this that made it clear that the patient was not yet cured, even though the cure would not be a matter of getting him to accept that the earth was flat. But not everyone is a physician, and what the times demand has considerable influence in the question of madness. Yes, at times one might almost be tempted to suppose that having modernized Christianity, the modern age has also modernized Pilate’s question, and that its longing to find something to repose in proclaims itself in the question: What is madness? If every time his gown reminds him that he has to say something, a privat-docent says de omnibus dubitandum est and writes briskly away on a system in which, on every other point, there is internal evidence enough that this man has never doubted anything – he is not considered mad.

Don Quixote is the prototype of the subjective madness in which the passion of inwardness embraces a single finite fixed idea. But, when inwardness is absent, we have the madness that rattles away and is just as comic, and which one could wish some experimental psychologist were to portray by taking a handful of philosophers of the kind and bringing them together. When the madness is a raving inwardness, what is tragic and comic is that this something, which is of such infinite concern to the unfortunate, is some fixated particular that is of no concern to anyone.

But when the madness is absence of inwardness, what is comic is that, although the something which the blissful individual knows is indeed the truth, the truth that concerns the entire human race, it does not concern the much-respected rattler in the least. This is a more inhuman kind of madness than the other. One shrinks from looking the former in the eye, lest one plumb the depths of his ferocity; but one dare not look at the other at all, for fear of discovering that his eyes are not real but of glass and his hair made from a carpet-mat, in short, that he is an artificial product.

http://users.clas.ufl.edu/burt/kierkegaardconcludingunscientificpostscript.pdf