ABSTRACT
The methods of psychology are, in general, the two methods of every science: description (that is, analysis and classification) and explanation. Its facts are not the common, independent, externalized facts of the physical sciences, but the inner facts, selves, and ideas. In an extreme sense, all is grist that comes to the psychologist’s mill. The apparent facility of introspection is, however, one of its greatest dangers. It is true, therefore, as many psychologists have shown, that introspection is never of the immediate present, but is rather a case of memory, and subject, therefore, to all the uncertainties of memory. Repetition of phenomena insures accuracy of analysis, and makes it possible to verify the results of a single observation; isolation of conditions narrows the object of study, and avoids the distraction of the observer’s attention; and, finally, variation of conditions makes it possible to explain a phenomenon exactly, by connecting it with those conditions only which it always accompanies.
