The author comments on “Operational thinking” (La “pensée opératoire”), a paper by Pierre Marty and Michel de M'Uzan at the 23^rd Congress of French-Speaking Psychoanalysts in 1962, in the light of the evolution of contemporary psychosomatic practice at the Paris School and shows how this text constitutes the “the occult part” of the report by C. David and M. Fain in relation to which it is complementary. A discussion follows on the notion of “operational thinking”, understood not as the result of mental failure but rather as a drastic defence linked to traumatic states.