Cumulative Record. Chapter 28: The Operational Analysis of Psychological Terms. Quote 35

None of the conditions which we have examined permits the sharpening of reference which is achieved, in the case of public stimuli, by a precise contingency of reinforcement . . . It is, therefore, impossible to establish a rigorous scientific vocabulary for public use, nor can the speaker clearly “know himself” in the sense in which knowing is identified with behaving discriminatively. (p. 422)