Thought pursues identity in order to unify its causality; the term thought identity designates the process of cognitive determination that it forms with its object, even if the latter is of an imaginary order.
With Sigmund Freud's work in The Interpretation of Dreams (1900a), the problem of identity saw a radically new approach in relation to the notion of perceptual identity and the respective aims of the primary and secondary processes.
Formal logic, a legacy from Aristotle, establishes identity as the criterion of unity of the thinkable, as the condition of possibility of thought itself, independent of its "matter." Practical thought makes effectiveness—that is, the successful transformation of the object—the criterion for appropriate, pragmatic thought. Imaginary or fantasmatic thought seeks its "thought identity" in independence—a direct source of pleasure—relative to practical or theoretical ends.
Philosophy, especially speculative philosophy (Hegel) sees the idea, the absolute determination of the concept, as the attainment of the goal of thought, in which an identity relation exists among the relative and exclusive practical, theoretical, and imaginary identities, as absolute knowledge. In this view, "ideological" thought identity represents the alienated current of the goal of identity pursued by a mode of thinking whose method is always and everywhere the active immobilization of thought, resulting in dogmatism, exclusivism, negation of the thought of the other, "group think," and the like.
Freud's distinction between the primary and secondary processes makes it possible to differentiate between thought identity, which is the aim pursued by thought by means of the secondary process, and perceptual identity, which is the aim pursued by hallucination by means of the primary process. In Freud's view, the aim is "practical" in that it always involves passing from one situation to another in accordance with desire. Hallucination short-circuits the detour necessitated in the effort of thinking, meaning that pleasure is not its condition even though it may remain its aim, and it takes the route of the death instinct rather than that of the life instinct; this explains the connection between thought identity and Eros. As Sophie de Mijolla-Mellor showed in Le Plaisir de pensée (1992), Freud distinguished practical and fantasmatic thought from thought in the form of true research or critical thinking; the latter do not make pleasure and its production the criteria for thought identity. For this reason, critical thinking and pure research alone are capable of producing a cogitative determination that is independent of perceptual identity.
See also: Experience of satisfaction; Perceptual identity.
Freud, Sigmund. (1900a). The interpretation of dreams. Parts I and II. SE, 4-5.
Lagache, Daniel. (1961). La psychanalyse et la structure de la personnalité. Colloque de Royaumont, 1958. La Psychanalyse, 6.
Mijolla-Mellor, Sophie de. (1992). Le plaisir de pensée. Paris: Presses Universitaires de France.