The formulation of any new way of thought begins with the trial rephrasing in many different ways of a single, as yet ambiguous theme. As the fisherman tries all kinds of rods, and the fencer all kinds of bamboo swords until he finds one whose length and weight suit him, so, in the formulation of a way of thinking, an as yet imprecise idea is given experimental expression in a variety of forms; only when the right measurements and weight are discovered does it become part of oneself.