This text aims to point out a number of contradictions inherent in Piaget's work (or in other people's interpretations of Piaget's work) and discusses the validity of some of the accepted ideas about it. First, we link Piaget's positions, as expressed in the Circle of Sciences, with the traditions of scientific epistemology, a link which, due to the closed nature of the discourse, is not always apparent. In consequence, perhaps, many commentators on Piaget's work have tended to consider as specific to genetic epistemology problems which have confronted other areas of psychological research. Second, we analyze the dialectic of development, and conclude that it is a genuine dialectic, although to un extent cushioned by the central notion of ccequilibrium)). This is the same as saying that Piaget is a sdialectic structuralistw, ensuring functional continuity and stimulating action as the motor of change, ut the expense of limiting himselfto a centred, ruptureless change. Finally we examine the scope ofgenetic epistemology, and state that in spite of its biological roots its natural frontiers are the frontiers of human thought: its application to the field of animal cognition may be seriously hindered by a range of shortcomings.