In clinical psychoanalysis, the surface is defined as the level of observables. This is the objective anchorage of psychoanalytic science. Surface material is not synonymous with conscious, with ego work or with the defences.

To understand the psychic realities underlying the clinical manifestations, the analyst uses the algorithmic and heuristic approaches. These are the investigative strategies psychoanalysis has in common with any other scientific discipline. The former involves a direct search for clarifying associations. The latter is characterized by clinical hypotheses (interpretations), whose confirmation lies in the analysand's responses.