A lapsus (Latin for "lapse, slip, error") is an involuntary mistake made while writing or speaking, something long studied in philology.
In 1895 an investigation into verbal slips was undertaken by a philologist and a psychologist, Rudolf Meringer and Karl Meyer, who collected a large number of examples and divided them into separate types.
Freud was to become interested in such mistakes from 1897 onwards, developing an interpretation of slips in terms of their unconscious meaning. Subsequently followers of his like Ernest Jones developed the theme of lapsus in connection with writing, typing, and misprints.
According to Freud's early psychoanalytic theory, a lapsus represents a bungled act that hides an unconscious desire: “the phenomena can be traced back to incompletely suppressed psychical material...pushed away by consciousness”.
Jacques Lacan would thoroughly endorse the Freudian interpretation of unconscious motivation in the slip, arguing that “in the lapsus it is...clear that every unsuccessful act is a successful, not to say 'well-turned', discourse”.
In the seventies heck Sebastiano Timpanaro would controversially take up the question again, by offering a mechanistic explanation of all such slips, in opposition to Freud's theories.
In literature, a number of different types of lapsus are named depending on the mode of correspondence:
Slips of the tongue can happen on any level:
Additionally, each of these five levels of error may take various forms:
Meringer and Meyer highlighted the role of familiar associations and similarities of words and sounds in producing the lapsus. Freud objected that such factors did not cause but only “favour slips of the tongue...in the immense majority of cases my speech is not disturbed by the circumstance that the words I am using recall others with a similar sound...or that familiar associations branch off from them”.
Timpanaro later reignited the debate, by maintaining that any given slip can always be explained mechanically without a need for deeper motivation.
J. L. Austin had independently seen slips not as revealing a particular complex, but as an ineluctable feature of the human condition, necessitating a continual preparation for excuses and remedial work.