L'actualisation du futur en économie : la succession temporelle des "moi" et des générations

When dealing with time, neoclassical rationality involves foresight. Thus, forward-looking and time-consistent intertemporal choices depend fundamentally on the way people discount the future - or rather its representation -, whether it concerns future resources (rate of interest) or satisfactions (time preference). Discounting procedures encounter two problems : - The heterogeneity of time, being discontinuous, irreversible or unpredictable, which is here attributed to the limits to human knowledge, comprehension and control, concerning one's self or one's environment. Discounting becomes more difficult in the presence of uncertainty or liquidity constraints, and even questionable when it wants to abolish irreductible differences in the experiences of historical generations. - The more or less subjective nature of the variable considered. Thus, pure time preference - which must be clearly distinguished from the rate of interest, the effects of uncertainty and the age variation of tastes - concerns the relation of "opacity" and "alterity" between present and future selves : linked to the notion of an existential project, it becomes discontinuous at random or decision nodes of the life-cycle. This preference allows to explain temporary or permanent myopic behaviours that preserve time consistency, leading to a richer concept of the subjective behavioral horizon for a rational agent.