Mentalism to Behaviorism

"In reaction to the intellectual indiscipline and clinical impotence of psychoanalysis, a mindless psychology – a psychology that excluded mind – became quite popular, eventually developing into an orthodoxy, at least among psychologists, with a little church of its own. The data of consciousness, pronounced the popes of behaviorism, were not susceptible to scientific verification; therefore they should be excluded from scientific enquiry. Instead, psychology should study only verifiable and measurable inputs and outputs, stimuli and responses, for whatever happened between input and output, stimuli and responses, was inaccessible to verification and measurement."
-Theodore Dalrymple