The author points out how some psychoanalytical concepts that were considered as fundamental and unchangeable are actually changing. Child Psychoanalysis with its “infant psychoanalysis” (babies and parents) and other psychological sciences have contributed to this development. Nevertheless, many psychoanalysts have not taken this new knowledge into account. The author ascribes it to the lack of an epistemological distinction between “describing” (facts) and “explaining” (hypotheses), that is, between what are known as discoveries in psychoanalysis and what are theories instead. No theory can be a discovery but rather a hypothetical conceptual instrument trying to explain discoveries. Freud's Metapsychology is a hypothetical instrument which needs to be changed today, since the progress of psychoanalysis and other sciences allows for better instruments. The author wishes for studies which may outline other explicit metapsychologies that may better explicate what is being observed.