Kein Mensch ist so wichtig, wie er sich nimmt. - Immanuel Kant

A man shouldn’t claim to know even himself as he really is by knowing himself through inner sensation — i.e. by introspection. For since he doesn’t produce himself (so to speak) or get his concept of himself a priori but only empirically, it is natural that he gets his knowledge of himself through inner sense and consequently only through how his nature appears and how his consciousness is affected. But beyond the character of his own subject, which is made up out of these mere appearances, he necessarily assumes something else underlying it, namely his I as it is in itself. Thus in respect to mere perception and receptivity to sensations he must count himself as belonging to the sensible world; but in respect to whatever pure activity there may be in himself (which reaches his consciousness directly and not by affecting the inner or outer senses) he must count himself as belonging to the intellectual world — though he doesn’t know anything more about it.

…sogar daß ihm auch wohl Philosophen, als einer gewissen Veredelung der Menschheit, eine Lobrede halten, uneingedenk des Ausspruchs jenes Griechen: »Der Krieg ist darin schlimm, daß er mehr böse Leute macht, als er deren wegnimmt«.

...We find that the more a cultivated reason applies itself with deliberate purpose to the enjoyment of life and happiness, so much the more does the man fail of true satisfaction... even from the sciences... they find that they have, in fact, only brought more trouble on their shoulders rather than gained in happiness; and they end by envying rather than despising the more common stamp of men who keep closer to the guidance of mere instinct, and do not allow their reason much influence on their conduct... [T]here lies at the root of these judgments the idea that our existence has a different and far nobler end, for which, and not for happiness, reason is properly intended...