Bernheim begins with the idea that minds are innately social. They develop in tandem, thrive in community, and therefore are porous to ideas—and this explains suggestion. Suggestibility is an essence of being a mind. Freud, however, began with the Cartesian ontology of minds as basic substances that existed in isolation. For him, the fact of suggestion was a mystery that needed explanation.

This supposition influenced the entire course of psychotherapy. Freud’s solution to the puzzle: only internal intrapsychic conditions would leave one person susceptible to the suggestive influence of a non-self agent. Hypnosis was not a natural effect of tandem minds, but a pathology that depended on the intra-personal pathology of possible autosuggestion. Weird effects inside the therapist–patient encounter were produced by weirdnesses inside the patient (alone).