As Barkley says, we have to look at what Say said and what Say did not say. At the end of the day, Say's Law, in its Classical (not neoclassical) form looks like the national income accounting identity (more or less). Production generates income sufficient to purchase that output. 'Sufficient to buy', but that is not the same thing as 'will necessarily be bought'. In the neoclassical version, interest rate variations guarantee that any income not spent on consumption will be invested, but I have never seen anything like that in Ricardo or Smith. The Classics believed savings would generally be invested for various reasons, some institutional (social class), others social-psychological (to better one's condition so to be the object of sympathy), but they had no *theory* that guaranteed that all income generated by productive activity would necessarily be spent to purchase the entirety of that output. Furthermore, and most importantly perhaps, there is nothing in the Classical version that says that this is operating at the full employment level of output. So production might generate income sufficient to purchase the entirety of that output, but the level of output is not full employment. All the Classical authors recognized the phenomenon of unemployment. In the neoclassical version, not only do you have Say's Law in the strong form of 'will necessarily be bought' but there is also the tendency to full utilization of resources, including labor (under certain assumptions, etc.). The more I think about it, the more the real economy seems better depicted in the Classical authors, rather than the neoclassical. And despite their own stated distance from what they termed the 'classics', in many ways Keynes, Veblen, Schumpeter, and others seem closer to the Classics. None of them were 'right' about everything; in fact they were probably wrong more than they were right. But their mistakes are still more helpful to me in understanding the contemporary political economy than Freakonomics or whatever is in fashion these days. Mathew Forstater