and does not clash with our convictions, comes before us, we desire it to be true; that is, we suppose that it is true, and we act as if it were true, considering it as true provisionally, and awaiting the consequences. If those consequences are favorable, and if the idea does not prove to be in opposition with the ideas we already possess and with those of other men, we admit it into the society of our established truths, and retain it until some change of interests or some alteration of conditions ousts it in favor of some other fresher and more useful truth. Schiller, then, defines truth as "that manipulation of data which turns out upon trial to be useful, primarily for any human end, but ultimately for that perfect harmony of our whole life which forms our final aspiration."
That which is true is useful. There may be ideas which are at the same time false and useful, but there is no such thing as an idea which is at the same time useless and true. Every hypothesis which is without utility is either false or insignificant. To adopt the Platonic terminology, the True is a form of the Good, and "every act of human knowledge is potentially a moral act."
Thus it is evident that Schiller does not consider truth as a thing fixed and dead, but as a thing changeable, plastic, dynamic. Truths are born and die, decay and are renewed continually.