Comparisons of Classical and Keynesian thought. In the comparison of the two thoughts one must understand that Classical thought is one that has been around longer than Keynessian and it was in all probability the only real school of thought from 1776 to the 1930's. The Classical thought is one that had its origins in Britain and with British's economists. As early as Adam Smith and until the great depression, most all economists were Classical economics. As a whole they believed that the self-correcting mechanisms of a market economy would continually guide the economy toward full output and full employment. Market prices