Freud's major revision of his drive theory, elaborates on the struggle between two opposing drives. In the first few sections, Freud describes these as Eros, which produces creativity, harmony, sexual connection, reproduction, and self-preservation; and the "death drives" (what some call "Thanatos"), which brings destruction, repetition, aggression, compulsion, and self-destruction.

In sections IV and V, Freud posits that the process of creating living cells binds energy and creates an imbalance.