The accuracy of all scientific observation depends upon a common accord of sense perceptions among the observers. This is shown upon analysis to be really the essence of a common agreement in terms. But we are accustomed to employ one mode of evaluation within the realm of objective phenomena and a quite different mode within the sphere of our subjective images. In the field of psychiatry, in which habitually personal feelings become the materials of an objective enquiry, we fail to apply the exact methods appropriate to the scientific laboratory of objective observation. Psychopathologists