My thesis is that liberal and progressive education models respectively refer to dual and unitary conceptions of intellectual development, and that these differences account for their pedagogical antagonisms. I test the validity of this argument by using it to account for the evolution of Western pedagogy and the fate of liberal and progressive education. I introduce the dualist epistemological premises of the major educational models that have followed one after the other in the history of Western education. Then, I account for the impact of classical empiricism, and later evolutionary doctrines, on the discredit of liberal education and the emergence of educational progressivism. Progressive educational conceptions are rooted in a representation of humankind developed under the influence of the Darwinian revolution. They justify an adaptive model of the mind within the framework of a functionalist psychology. According to alternative currents of modern educational thought, the use of auxiliary means of thought marks a rupture with human biological development. These currents underpin a dual conception of human reason according to which rational or theoretical understanding is a sui generis dimension of thought. They offer support for a modernized version of liberal education.