In Book I, Keynes introduces the fundamental postulates of what he considers to be the classical theory of value and production, in order to highlight some of the tacit assumptions of the prevailing schools of thought regarding employment. He shows that, while the classical theory holds that “supply creates it own demand” and that aggregate demand will always meet aggregate supply and that this mechanism allows production to scale up to full employment, such is not necessarily the case. Instead, Keynes asserts that volume of employment is constrained by other factors, namely by the intersection of the aggregate demand function (how much consumers are willing to pay, as a function of employment volume) and the aggregate supply function (how much entrepreneurs are expecting to make as proceeds). Keynes says that, even if real wages are equal to or less than the marginal utility of labor (making wages worthwhile to the entrepreneur) and equal to or greater than the marginal disutility of labor (making wages worthwhile for workers), employment volume cannot be scaled up unless aggregate demand is greater than aggregate supply.