On the Relationship of the Psychological and the Physical in Psychophysics

This article presents a theory of the relationship of the psychological and the physical and uses it to formulate a new kind of meaningfulness principle for psychophysical application. This new principle calls into question the psychological relevance of many kinds of quantitative psychophysical relationships. As an illustration, it is used to study comparisons of sensitivity involving Weber fractions, particularly comparisons across sensory modalities. The methods of the illustration extend easily to other psychophysical situations.