This paper considers the claim that C. G. Jung used a Lamarckian model of evolution to underwrite his theory of archetypes. This claim is challenged on the basis of Jung's familiarity with and use of the writings of James Mark Baldwin and Conway Lloyd Morgan, both of whom were noted and forceful opponents of neo-Lamarckian theory from within a neo-Darwinian framework. The paper then outlines the evolutionary model proposed by Baldwin and Lloyd Morgan, which has come to be known as Baldwinian evolution or the Baldwin effect. This model explicitly views psychological factors as central to the evolutionary process. Finally, the use of Baldwinian thinking in contemporary theorizing regarding language and other symbolic systems is reviewed and suggestions are made regarding the implications of Baldwinian models for theory building in analytical psychology.