Quite the stupidest remark that could be made about the classical economists, and many have made it, is that they had no explanation for the Great Depression. Wages, prices, taxes, tariffs and regime uncertainty can explain it all. Cannan, for one, knew that. What economists could not produce was a political process sufficient to reduce the reserve price of labour. W H Hutt is – in his own way – most clear on this.

“John Stuart Mill’s profound insight that demand for commodities is not demand for labor, which Leslie Stephen could in 1878 still describe as the doctrine whose “complete apprehension is, perhaps, the best test of a sound economist,” remained for Keynes an incomprehensible absurdity” (Collected Works, vol. 9., p. 249).

Machlup’s remark identifies something important, I think. Keynes was a serious guy. He gave us the last best attempt to save induction with his Treastise of [on?] Probability, for example. He was a real thinker. I also think we can all get lots of sustenance from Chapter 12. It is for a reason that Keynes launched a revolution in economics. But all Keynes’s talents and depth did not necessarily make his economic theory right or even very good. It does seem fair to say with Machlup that he was not a good economic *theorist*.

Roger Garrison taught me that Keynes violated “Mill’s fourth,” i.e. the fourth of Mill’s “four fundamental propositions regarding capital.” The 4th is “Demand for commodities is not demand for labor.” It seems this was once the benchmark test for whether you were or were not an economist. By that standard Keynes didn’t make the cut because C & I move together in his system. Admittedly, he had sophisticated reasons for rejecting Mill’s 4th and Say’s law. He was not merely clueless. But in some sense the result was more anti-economics than economics as previously understood.

thats the reason why Keynes comment on Hicks Value and Capital, a book almost contemporary to the GT, was about “…a book written by an obviously clever man, and at the same time, almost empty of contents”.