A sustained misconceptualisation of a theory leading to invalid applications and inferences indicates a failure in the scientific process. This has repeatedly occurred with Freud's theory of repression, a cornerstone of psychoanalytic theory. This paper traces the development of Freud's theory of repression and compares this with the "common view" found in mainstream psychology: the motivated forgetting of trauma. A fixation with Freud's original, and superseded theory (1893-1897) ignores the theoretical developments that constitute mature psychoanalysis (1900-1940), and has impacted upon attempts to test Freudian theory and the current "recovered memory" debate. Although certain accidental factors contribute to this misunderstanding, the sustained failure to comprehend Freudian repression reveals a breakdown in the process of critical inquiry. Implications for psychology as a whole are discussed.