From “Science: Problems, Aims, Responsibilities” (1963):
There is only one way to learn to understand a serious problem — whether it is now purely theoretical or a practical problem of experimentation. And this is to try to solve it, and to fail. … Even if we persistently fail to solve our problem, we shall have learned a great deal by having wrestled with it.
— Karl Popper, “Science: Problems, Aims, Responsibilities” (1963), The Myth of the Framework, ed. M.A. Notturno, (London: Routdedge, 1994), p. 99.