Samuelson on Induced Innovation
1) Like a too-powerful headlamp, Professor Samuelson's brilliant article on induced innovation illuminates much but casts other matters into greater obscurity.' In this short note, I am hoping to make the illumination a bit more evenly-diffused. On the whole I shall argue that where there is a differentiation of the Samuelson from the WeizsackerKennedy product, Samuelson himself has tended to exaggerate the quality difference involved. Before coming to this, however, I should like first to allude to one aspect of the matter about which Samuelson has scarcely commented. 2) I think there is a rather fundamental difference in what might be called the methodological intention of our two approaches. Following Kaldor,2 and recognizing the very great difficulty in principle and impossibility in practice of distinguishing factor substitution from bias in innovation. I had hoped that the innovation-possibility frontier might be able, so to speak, to swallow up the traditional production function and replace it altogether. Samuelson, on the other hand, by adopting the factor-augmenting form for the production function has allowed the production function to do the swallowing up. Each of these two approaches has its weakness and its strength. The strength of the one is the weakness of the other, and vice versa. The weakness of the Samuelson approach is the great reliance still placed on the tenuous concept of the production function, a reliance that the KaldorKennedy approach successfully avoids. The weakness of the Kaldor-Kennedy approach is that it fails to provide an explanation of the determination of prices in the short run, while the Samuelson approach is admirably suited to doing just that. While I still have hopes of the Kaldor-Kennedy approach, I do not think it can be taken much farther until some reasonably convincing alternative explanation of the determination of prices in the short run can be built into it.3 Without beconming a confirmed factor augmenter, for the purpose of the rest of this note I am prepared to go along with the factoraugmenting form of the production function.4 Let me at the same time accept everything that Samuelson wrote concerning stability conditions together with the implied criticism that my own piece was weak on stability questions. 3) Having conceded this much, I am going to put up much more resistance on most other points. The core of Samuelson's own analysis is in his section II. Stability questions aside, the reason and the only reason why he obtains a different result from mine in my own discussion of the one-pr-oduct model is that he has replaced one of my assumptions by one of his own.5 In the place of my assumption that the rate of interest is constant, Samuelson has assumed that capital, in natural units, is accumulati g relative to in natural units. The reason why I have not utilized the Hicksian insight that capital tends to grow relative to labor is that I have no need of it. Since a determinate rate of capital-deepening comes out as one of the results of my analysis of the one-product model, it would obviously be worse than superfluous to incorporate it also as an assumption. 4) I do not see any particular reason why a model which assumes an exogenous rate of growth of capital relative to should be regarded as superior or inferior to one which assumes a constant rate of interest. The most one might say is that the former is more appropriate for relatively short-run analysis and the latter for relatively long-run analysis. Both models fail to explain the fact that the interest or profit rates show no clear trend upward or downward. For this reason, I would agree that my own theory is not a complete theory of the constancy of distributive shares. but rather a theorv contingent ' A Theory of Innovation Along KennedyWeizsacker Lines, this REVIEW, XLVII (Nov. 1965). See also my own Induced Bias in Innovation and the Theory of Distribution, Economic Journal (Sept. 1964). Since Samuelson is kind enough to mention the seminar held at M.I.T. on May 28, 1964, may I take this opportunity of acknowledging the very great courtesy shown by himself and his colleagues at M.I.T. in giving me a hearing on a date and at a time that for them could hardly have been more inconvenient. May I also take this opportunity of mentioning again my indebtedness to Professor Ahmad, of the University of Khartoum. Regrettably, his name was misspelled in the acknowledgement in the Economic Journal. I have not had the advantage of seeing Weizsacker's unpublished paper. 2Essays on Economic Stability and Growth (Duckworth, 1960), 264 et seq. 3 I suspect Kaldor might claim that he had provided an alternative explanation -but I am not sure that it is convincing as yet. 4 With the reservation that augmenting can be negative as well as positive. See below, section 5. 5 See Samuelson, op. cit., 348, footnote 3. With reference to that footnote, please observe that, in Kennedy's case, the Harrod-neutral result is not supposed to come about, it does come about!