A major theme of Vygotsky‘s research in the latter part of his life was the theme of concept formation or conceptual development in child development. He argued that the acquisition ofmature scientific (academic) concepts forms the crowning achievement of adolescsence. Mature conceptual thinking positively influences the cognitive domain but also the aesthetic reactions and emotions. Conversely, the breakdown of conceptual thinking in pathology will lead to severe intellectual impairment but also to emotional dullness etc. In this paper it is claimed that this view is highly interesting but a number of criticisms are raised. Specifically, it is argued that (l) the resulting view is overly rationalistic; (2) the notion of scientific concepts seems to imply a somewhat static view of science; and (3) Vygotsky was perhaps too optimistic about the possibility of transfer of scientific (conceptual) thinking to other domains.