The research available on the causes that determine the growth rate has privileged the neoclassical approach, and more recently a version of it known as 'new' growth theory, which tends to consider economic expansion as a process where the dynamic of the inputs and their productivity takes center stage. No specific role is ascribed to aggregate demand to which is only recognised a temporary effect on the level of resources utilization. Totally different is the demand side approach in which the rate of growth in production is entirely explained by demand-side factors. Moreover, in such framework, the aggregate demand actually determines the dynamic of the inputs. Even those who have chosen to approach this view in a more flexible 'eclectic' way, do tend to emphasise the role of the demand in the growth process in a way at least equal to that attributed to supply side factors. The objective of this work is to examine the main contents of the keynesian approach to the economic growth and to confront them critically to the neoclassical one. More generally we have intended to focus our attention on some important aspects of the growth process that the most consolidated academic studies and lines of thoughts have tended to keep under marginal investigation given their focus on the supply-side economy.
