Choosing the right fictions of scientific law.

Fictions are well established in the theory and practice of civil law; similar importance is here claimed for fictions in the theory and application of scientific law. A puzzle from quantum mechanics, previously referred to in this Journal [Am. J. Physiol. 238 (Regulatory Integrative Comp. Physiol. 7(: R277-R290, 1980], is reinterpreted by suggesting quantum logic as a source of relevant fictions, which indicate a solution to that puzzle. Another physiological application of quantum theory suggests that the concept of "the state of the brain" may, in its usual classical sense, not be useful for an individual brain--but may well be suggestively modeled by a quantum state. The notion of "myths," usually only pejoratively applied in positivistic writings, is suggested for rehabilitation, in view of their helpful function (often unnoticed) even in positivistic thinking. Finally, an example of a biological simulation (of a tumor by a cell culture) is presented, to show that its multilayered fictionalizations illustrate the surprising fact that a simulation that is insulated from the system being simulated can be logically more powerful than any uninsulated simulation.