Our interest, the interest of psychoanalysts in early development, has its origins in an accident, a chance, an unintended and unexpected event in the treatment of a hysterical patient: the observation that her hysterical symptoms disappeared when she remembered with strong affects certain relevant childhood experiences. From this point, thanks to Freud’s genius, a vast body of knowledge and of speculation has grown and continues to grow. We all work with theories which have been well established through trial and error, checking, modifying, re-checking, established because a number of workers have found them indispensable for the understanding of clinical phenomena. We equally use a number of hypotheses, again because we find them operationally valuable, though we maintain some doubt about their ultimate correctness, and while we do use them we are ready to give them up or accept some modification. If we are truly scientific, we shall also be ready to give up or accept modifications in respect of what I have called the established theories. But I think it is true to say that in fact we do distinguish our working tools as regards our readiness to change them. With my initial remark I have stated again what has been stated repeatedly; psychoanalysis is an empirical science. The clinical situation is its fertile matrix. Moreover-and this point needs to be stressed-it is also its raison d’être for the psychoanalytic clinician. The practising psychoanalyst wants the scientific concepts because and in so far as they serve his practical purpose and serve as tools.