Abstract: “The Baldwin effect” stands for a wide variety of ways in which learn ing can be conceived as guiding adap tive evolution ary change. An analysis of the history of this notion reveals that it does not reliably refer either to a theory-neutral empirical phenomenon or to a single theoretical hypothesis. On the contrary, articulations of the general idea depend on distinctive, but in commensurable, theoretical backgrounds. In reconstructing the conceptual history of the Baldwin effect I hope to support contemporary explorations of idea by encouraging the articulation of new theoretical frameworks in which it might make sense. I am therefore more of a Baldwin booster than a Baldwin skeptic.