Philosophy as practice does not mean its restriction to utility or applicability, that is, to what serves morality or produces serenity of soul.
Karl JaspersEven scientific knowledge, if there is anything to it, is not a random observation of random objects; for the critical objectivity of significant knowledge is attained as a practice only philosophically in inner action.
Karl JaspersIf philosophy is practice, a demand to know the manner in which its history is to be studied is entailed: a theoretical attitude toward it becomes real only in the living appropriation of its contents from the texts.
Karl Jaspers