“Concrete” patients manifest resistance to interpretation per se. Their apparently primitive thinking is the result of complex psychodynamics, explicable in terms of the mechanisms of wish fulfillment and a revised theory of fetishism. The general thesis is that an unconscious equation of differentiation with overwhelming tension leads to a global process of defense against the differentiating function of the analytic frame. The wider implications of this theory can be integrated with Freud's mostly unknown late attempt to generalize the theory of fetishism.