Ex ante and Expost in Says’ Law

Ex ante and Expost in Says’ Law The statement that supply creates own demand or equivalently that the aggregate investment equals the aggregate saving always holds good in the ex post sense since it is simply an accounting identity. Say’s law of markets, however, states that these two are equal in ex ante sense, i.e., the total quantity which people produce i.e., aggregate supply must be equal to the toal quantity which they plan to buy i.e., aggregate demand. - - Theories of Employment and Income