The third of this kind of principles is : matter neither originates nor perishes; all the changes in the world concern form only ; a postulate which … - Immanuel Kant

Only by what a man does heedless of enjoyment, in complete freedom and independently of what he can produce passively from the hand of nature, does he give absolute worth to his existence, as the real existence of a person. Happiness, with all its plethora of pleasures, is far from being an unconditioned good.

...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...

An appeal to the consent of the common sense of mankind cannot be allowed, for that is a witness whose authority depends merely upon rumor. Says Horace: Quodcunque ostendis mihi sic, incredulus odi.