This posthumous paper, edited by John Klauber, suggests that if Freud had 'anticipated himself by even a year or two, and … introduced the structural hypothesis, the [pragmatically successful] libido-aggression dual drive theory … could well have been established without the obscure and devious bypath' of the theory of the death instinct. Pratt believed also that the two instinct theories, libido-aggressive and Eros-Thanatos, are fundamentally antithetical. The paper examines the nature of the several components in these theories: life, death, instinct, phylogenetic and teleological concepts. Pratt, according to Klauber, favored the view that the id is not merely an 'unorganized reservoir of drives', but rather that it is a highly complex adaptive structure. If so, 'sexualization and aggressivization' of eating and sleeping, for example, are not the only sources of disorder in these instinctual functions: biological forces also explain such disturbances.