I must confess that my own first reaction to the General Theory was not at all like that of Keats on first looking into Chapman's Homer. No silent watcher, I, upon a peak in Darien. My rebellion against its pretensions would have been complete except for an uneasy realization that I did not at all understand what it was about. And I think I am giving away no secrets when I solemnly aver-upon the basis of vivid personal recollection-that no one else in Cambridge, Massachusetts, really knew what it was about for some 12 to 18 months after its publication. Indeed, until the appearance of the mathematical models of Meade, Lange, Hicks, and Harrod there is reason to believe that Keynes himself did not truly understand his own analysis.
Fashion always plays an important role in economic science; new concepts become the mode and then are passé. A cynic might even be tempted to speculate as to whether academic discussion is itself equilibrating: whether assertion, reply, and rejoinder do not represent an oscillating divergent series, in which-to quote Frank Knight's characterization of sociology-"bad talk drives out good."
In this case, gradually and against heavy resistance, the realization grew that the new analysis of effective demand associated with the General Theory was not to prove such a passing fad, that here indeed was part of "the wave of the future.--Paul Samuelson (1946) "Lord Keynes and the General Theory," Econometrica. 187-188.
As I noted yesterday, an invited comment on Backhouse's biography of Samuelson has had me take a second look at Samuelson's biographical sketches and obituaries. It's testimony of Samuelson's confidence and rhetorical abilities that his lack of initial understanding of the General Theory is treated as a problem of the General Theory (and even Keynes). It is notable that he does not consider the obvious alternative suggestion that Cambridge, MA, was a relative intellectual backwater in 1936 (the year the General Theory appeared) and so unfamiliar with the new thinking developing in Cambridge England. (To his credit, in the rest of his essay, Samuelson provides some evidence for the latter half of that claim.)
As an aside, it is a bit peculiar to see a low estimation of sociology attributed to Frank Knight, the man most responsible of generating initial interest in (and translation of) Weber Stateside. One wonders if, perhaps, Samuelson's memory is failing him and that he is importing his own negative characterization of sociology (recall) into his memory of Knight's acerbic wit. My evidence for this suggestion is that when in a different obituary, he discusses Jacob Viner's ferocious use of the Socratic Method (indebted to the Harvard economist Taussig), Samuelson adds that graduate students who did not meet Viner's exacting standards "had no choice but to drop out or to transfer to the slums of political science or sociology." (JPE, 1972: 6) It's not impossible that the low estimation of sociology was more common among economists in Chicago, but we know from Stigler's citation practices that some read sociology and social theory rather seriously, and that it even influenced Milton Friedman's methodology.
Some other time I'll explore the significance of the proto-cyclical-equilibrium model of scientific fashions, a model that would certainly have some significance (recall) for professional philosophy (where the idea that ideas cycle in and out of fashion is itself a recurring fashion.)* I mention it here because the whole obituary is framed in proto-Kuhnian terms in which Keynes generates a scientific revolution (and in which differential response to the revolution is explained in terms of generational differences.) Later in the piece, Samuelson notes that textbooks break the cycle: "most important from the long-run standpoint, the Keynesian analysis has begun to filter down into the elementary textbooks; and as everybody knows once an idea gets into these, however bad it may be, it becomes practically immortal." (189) Samuelson was just finishing up his mega-influential textbook. (Luckily, in philosophy textbooks are not the dominant mode of instruction yet.)
Okay, let me get to the main point. Samuelson claims here that mathematics is the language in which by way of a model one understands an analysis. (The previous sentence is compatible with the further thought -- pressed by Samuelson's ironic critic -- that mathematics may well be many languages.) This is true not just of the readers of the General Theory, but also its author. Samuelson emphasizes the point later: "In it the Keynesian system stands out indistinctly, as if the author were hardly aware of its existence or cognizant of its properties."** Now, to be sure, there are two important truths lurking in Samuelson's position: first, that the meaning of a text may well escape or go beyond an author (and sometimes even may be so intended by an author)--I made that same point when discussing the debate between Plantinga and Hazony over biblical meaning. Second, sometimes, maybe often, an analysis in non-mathematical language is fuzzy or unclear or equivocal in ways that are only made transparent by a mathematical model. (A claim Samuelson would repeat regularly later in his rejection of verbal economics as opposed to mathematical economics.)*** Only later in life (1972), when discussing Viner's significance (he calls him both the "greatest neoclassical economist" and a "great eclectic"), does Samuelson relent on the point: "Jacob Viner was a respecter of mathematics, but also both critical and defensive about it. Let me make clear that Viner possessed in superlative degree what might be called native mathematical ability....But I now realize in retrospect that the subject of economics gained from having Viner concentrate upon those areas of wisdom and erudition for which he had a unique comparative advantage, and that more mathematical facility might merely have diverted him from his appointed task."
Samuelson does not consider an alternative interpretation: that in different ways, Meade, Lange, Hicks, and Harrod may have offered models inspired by the General Theory, but in their very formulation changed the meaning of the 'Keynesian' analysis.+ One can recognize the previous point while allowing that the new models may have had all kinds of uses (teaching, policy, transferring knowledge, etc.) made difficult by the General Theory. To argue that case is not my present charge (and I would have to re-familiarize with all the relevant models), although I have already suggested that Keynes's insights about the nature of true uncertainty were lost in the way his views got formalized. (I made some such point in a different context when discussing Carnapian explication.)
Strikingly enough, and Samuelson often buries his most important points in footnotes, he adds the following observation:
8 Indeed only in connection with Frank P. Ramsey's "A Mathematical Theory of Saving"...does he show interest in an esoteric theoretical problem; there he gave a rather intricate interpretation in words of a calculus-of-variations differential-equation condition of equilibrium. His reasoning is all the more brilliant -- and I say this seriously! -- because it is mathematically unrigorous, if not wrong. The importance which Keynes attached to this article is actually exaggerated and can be accounted for only in terms of his paternal feeling toward Ramsey, and his own participation in the solution of the problem. (196)
An uncharitable reading of Samuelson may suggests that he is committed to the idea that wrong mathematical reasoning is better than no mathematical reasoning (even if not wrong). A more charitable reading would suggest that he recognizes that sometimes insight does trump a wrong mathematical formulation, especially -- and this is not meant as criticism -- if it takes a Samuelson to discern the kernel of insight.