Abstract

Attempts to define scientific psychology by its object have regularly provoked lively controversies throughout the history of the discipline. Nonetheless, a consensus seems to have been reached early in the history of the discipline concerning the method of scientific psychology, described as “experimental”. Experimentation has imposed itself in most of the sub-disciplines of psychology as the indisputable means of establishing the validity of psychological knowledge. It is regularly considered the main demarcation criterion of a scientific psychology. As we will see in this chapter, this methodological consensus seems somewhat fragile. Beginning with Claude Bernard’s definition, to which the first experimental psychologists consistently referred, the experimental method has been refined and has undergone fundamental adjustments. We will try to show that these adjustments were made necessary by the relative inadequacy of the experimental method for testing the theoretical hypotheses of contemporary psychologists.