Abstract Freud's theory of slips of the tongue has been extensively criticized by Adolf Grunbaum and Edward Erwin. They argue that in an effort to make the theory plausible Freud relied on examples of speech errors that do not conform to his theoretical characterization of slips of the tongue. These examples have contributed to the impression that Freud's theory relies on a broader evidential base than it in fact does. Furthermore they argue that Freud has not established the existence of (...) a causal connection between repressed ideation and slips of the tongue. I argue that both of these criticisms are ill?founded because they are demonstrably based on misinterpretations of Freud's view and misreadings of the relevant texts. Grunbaum and Erwin have consistently mistaken the epistemic structure of Freud's view. I am less interested in defending Freud's view than in clarifying the relationships between assertion and evidence in Freud's theory of parapraxes. To this end I conclude with an argument to show that within Freud's theory there is no criterion for telling that any particular thought has previously been repressed, and that in the absence of such a criterion a fundamental assumption of the theory is unsupported. (shrink)