Principle of Permanence

The principle of constancy is Freud’s account of how a psychical system regulates energy while wishes seek satisfaction. Developed in the unpublished “Project for a Scientific Psychology” of 1895, it provides an early materialist framework for ideas that recur in The Interpretation of Dreams and later psychoanalytic writing.

Definition and Operation

Freud’s model treats nervous or mental energy as analogous to physical energy. It acts upon neurones, which energy charges, and circulates within a closed system, at times inhibited by contact barriers. Wishes arise within this system and seek satisfaction through the discharge of energy; at the same time, the principle of constancy tends to keep the system’s amount of energy constant.

The self or ego, conceived as an organization of neurones that remains charged with energy, connects the system to the external world. It can receive or inhibit outside stimuli. When energy is not connected to the external world through the ego, as in dreaming, it flows freely; when it is connected through the ego, its movement is weakened and inhibited.

Primary and Secondary Processes

The contrast between these forms of energy movement anticipates Freud’s distinction between primary and secondary processes. In the primary process, desire flows freely and takes no account of reality. In the secondary process, its flow is hesitant: desire must compromise with the demands of reality. The model therefore presents constancy not as the abolition of desire, but as a tendency that shapes how desire’s energy moves and is restrained.

Later Significance

The contrast between primary and secondary processes reappears at the end of The Interpretation of Dreams and, in Freud’s later writings, as the distinction between the id and the ego. The circulation of energy also returns as the movement of libido among objects of desire. The principle of constancy thus belongs to an early theoretical model, but its terms furnish a durable framework for Freud’s subsequent accounts of dreaming and psychic life.