This essay addresses the attitude of some leading Neo-Kantian philosophers toward scientific psychology and psychophysics. Early influential figures like Friedrich A. Lange counted Gustav T. Fechner’s psychophysical law among their allies in the rehabilitation of the Kantian standpoint. Later on, however, Neo-Kantian philosophers firmly rejected psychological measurement as a whole and harshly criticized the methods adopted by several psychologists of their time. For example, the Marburg mathematician and philosopher August Stadler reduced the validity of Fechner’s law to the mere physiological (...) sphere, and Hermann Cohen conceived the application of mathematical integration to human sensations as an inane enterprise. (shrink)