Hartmann's hopes for psychoanalysis becoming a general psychology and achieving the status of a natural science have not been realized. Today there are numerous models available to explain a variety of psychological data, some better suited than psychoanalysis. Furthermore, the place of psychoanalysis in either natural science or social science remains the subject of debate. Edelson states that psychoanalysis cannot explain everything that is psychological. Meissner, Smith, and Greenberg believe that at our current state of knowledge psychoanalysis is deficient as a comprehensive psychological theory. We believe that they are conveying a message — the message that there remain unexplored bridges within the body of Hartmann's work that will strengthen the explanatory power of metapsychology and classical psychoanalysis in the areas of experience, self psychology, and object relations. The structural theory and metapsychology remain as an essential starting point for developing any comprehensive understanding of the workings of the mind.