I am still reading the Backhouse intellectual biography. What a monumental effort! By comparison, it makes Sebastian Mallaby’s biography of Alan Greenspan look like a summer vacation project. But I recommend Mallaby to anyone. Backhouse is for people with a pretty narrow interest in the history of economic thought.
A few more comments.
1. Backhouse sees Samuelson as making a major contribution to clarifying Keynes. I disagree. At most, Samuelson provided the freshman interpretation. But for intermediate courses and above, Hicks was the go-to clarifier, and he preceded Samuelson. Backhouse agrees that the intermediate courses left Samuelson behind.
It seems that a lot of the initial confusion about the simple Keynesian multiplier concerned the process by which it was supposed to play out. You can write down Y = C + I + G and C = a + bY and then solve for Y and C in terms of the other letters, but nobody in the 1930s or 1940s thought in terms of such an instantaneous equilibrium. Instead, they thought in terms of a solution being ground out over time, iterating back and forth between the two equations. There were any number of plausible lag structures, and also a variety of plausible definitions of investment, consumption, and savings.
As Backhouse points out, in hindsight it appears that Keynesian economists were floundering unnecessarily in their attempts to deal with what we now regard as the simplest class of models. Perhaps without Samuelson the floundering would have been worse and more long-lasting. I am not convinced.
But the main reason I do not give Samuelson credit for clarifying Keynes is that Keynesian economics remains unclear to this day. And economists who call themselves Keynesians would be the first to admit that.
2. The conventional narrative is that Samuelson made mid-century economics. His prodigious talent shaped the profession. Backhouse sticks with this narrative.
I would pose an alternative narrative, which is that mid-century economics made Samuelson. Sometimes a movement needs to create a larger-than-life figure. In religion, the larger-than-life figure might be Christ or Mohammed or the Buddha. In a nation at war, it might be Napoleon or Churchill.
In the (seemingly) secular world of Olympic sports, the broadcast network will try to make a few athletes larger than life. And speaking of Keynes, he became a larger-than-life figure in the movement to promote activist macroeconomic policy.
With his unbounded ego, Samuelson moved easily into his heroic role. He was a legend in his own mind, given to overstating both the rigor of his mathematics and the significance of his analysis. Had he appeared at a different point in history, this might have earned him scorn and derision. But when Samuelson arrived as a graduate student at Harvard, there was a strong latent desire, particular among younger economists, to show that they were scientists and to show that they, unlike their elders, knew how to prevent and cure Depressions. So instead of pushing back against his arrogance, his peers heaped praise on his work. In the process, they were raising their own status relative to older economists while creating a new and more exalted public image of the economics profession.
By the way, I think that the same thing happened, to a lesser degree, with some of the stars of 1970s macro, such as Robert E. Lucas, Jr., and Christopher Sims. Some of their peers saw an opportunity to raise their own status by characterizing Lucas and Sims as intellectual giants who towered over everyone else.
My own view is that in economics there are no towering giants, in the sense of economists whose aptitude for the subject far exceeds that of others in their cohort. Some economists are a bit more creative than others, some work much harder than others (Samuelson was certainly exceptional in the efficiency and extent of his work effort), and some play the academic game much better than others. But the distribution of rewards ends up being much more skewed than the distribution of talent.