The task is to move beyond Marx’s proclamation that accumulation is the law of Moses and the prophets. Consequently, scholars have been regularly experimenting with various reduced-form behavioral equations in the quest to explain investment. We revert to neoclassical micro foundations because demand (supply) functions can be generated from the same source. At the same time, the macroeconomics of the economy is represented by an accumulation of capital equation in the classical sense. Although the dynamic equation is derived from a set of standard definitions and identities, the explanatory variables include all the important elements in the non-neoclassical growth model