The idea!

Werner Heisenberg, "Quantum Theory and Its Interpretation," in Niels Bohr: His life and work as seen by his friends and colleagues, ed. S. Rozental:

Bohr's tendency to philosophical generalization was often stimulated by very simple games. Once, when on a lonely road I threw a stone at a distant telegraph post, and contrary to all expectations the stone hit, he said, "to aim at such a distant object and hit it, is of course impossible. But if one has the impudence to throw in that direction without aiming, and in addition to imagine something so absurd as that one might hit it, yes, then perhaps it can happen. The idea that something perhaps could happen can be stronger than practice and will."