Role of Theory
“It is important to note that in spite of the checks, the character of the concept [of ultramicroscopic length] is changing, and begins to involve such things as the equations of optics and the assumption of the conservation of mass.”
“. . . They constitute a dangerous source of ambiguity . . . The infected ideas have two aspects: their own native impurity, plus all the additional impurities arising from mistaken interpretations . .
“the making of guesses is by no means an unmitigated evil . . Operationism can be of practical value,” Pratt, LMP, pp. 117- 121.