Three conceptualizations of men, society, and development are compared: mechanistic, mentalistic, and dialectical. The first two focus upon the individual, either as passive beings ceaselessly accummulating information given to them, or as active forces selectively constructing knowledge. Two examples of the dialectical paradigm, which emphasizes the developmental interpenetration of inner and outer constructions, are described: the study of memory and the study of language development. The implications for gerontology are discussed and summarized in reference to three concepts of time: absolute, relational, and dialectical.