treatment of certain mental diseases. It now regards itself as possessing a body {71} of doctrine of general applicability to mental phenomena, normal or abnormal. These principles are the product of laborious and minute inquiries into the working of the mind, rendered possible by the use of a characteristic method known as psycho-analysis. This method, which constitutes a definite and elaborate technique of investigation, is looked upon by those who practise it as the sole means by which access can be obtained to the veritable phenomena of the mind, and as rendering possible a truly objective view of the facts. It is no part of my purpose to examine the validity of psycho-analysis as a scientific method. It is enough to notice that the exponents of it completely repudiate the teachings of what I have called “common-sense” psychology, that they maintain that objectivity in the collection and collation of psychical facts is in no way to be obtained by the light of nature but demands very special methods and precautions, and that their claims to the possession of a truly objective method appear to be open to verification or disproof by actual experiment in the treatment of disease. Whatever value, then, psycho-analysis may ultimately prove to possess in solving the peculiar difficulties of psychological research, the evolution of it marks a very definite advance in principle and shows that it is the product of a mind determined by whatever effort to get to close quarters with the facts.
The body of doctrine enunciated by Freud concerns us more directly than the peculiarities of his method. Some very general and summary account may therefore be attempted as illustrating the characteristics of this vigorous, aggressive, and essentially “human” school of research.
The Freudian psychology regards the mind of the adult as the outcome of a process of development the stages of which are within limits, orderly {72} and inevitable. The trend of this development in each individual is determined by forces which are capable of precise definition, and the final product of it is capable of yielding to expert examination clear evidence of the particular way in which