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110 Piero Sraffaof Sraffa’s critiques to the foundations of the marginalist approach.The claim that such critiques only concerned the ‘lowbrow’ versionsof the marginalist theories 18 implied a retreat towards the rarefiedatmosphere of intertemporal general economic equilibrium models andabandonment of the assumption of a rate of profits uniform across thevarious sectors of the economy. 19Sraffa’s analysis also provided the foundations for criticisms of specificvarieties or of specific aspects of the marginalist approach.Among the critiques of specific streams of the marginalist approach,let us recall those proposed by Steedman on the theory of value and distributionas originally proposed by Jevons and by Wicksteed. 20 Pasinetticriticises Solow’s use of the Fisherian notion of the rate of return, whichSolow considers as ‘the central notion of capital theory’, by maintainingthat it indicates the return to society of an increase in savings (thedemand price of savings) and can be defined independently of the rate ofprofits, so that it could be used, together with the intertemporal preferencesof economic agents (the supply price of savings), to explain it. 21Of the critiques of specific aspects of the marginalist approach, let usrecall the criticism levelled at the Heckscher–Ohlin–Samuelson theoryof international trade. According to this theory, each country tends tospecialise in the production of those commodities that require relativelylarger quantities of those factors of production which are relatively moreabundant in that country. Critiques were originally proposed independentlyby Parrinello (1970) and by Metcalfe and Steedman (1972, 1973),to be developed in a long series of articles, in some cases attempting tobuild a ‘neo-Ricardian’ theory of international trade as well. 2218Occasionally recourse to analytical tools such as the aggregate productionfunction is justified with the distinction between ‘high-brow theories’, internallyconsistent but wholly irrelevant on the practical level, and ‘low-brow theories’,relevant for practical matters but based on foundations already recognised asmistaken. In the latter case, the use of more or less advanced mathematicaltools should not lead us to forget, as unfortunately happens all too often, thatthese contributions are precisely ‘low-level’ contributions, and as such should beexcluded from the field of economic science. Cf. Bliss (1970); Hahn (1982).19Cf. Garegnani (1970b, 1979); Roncaglia (1975, Chapter 6); and more recentlyKurz and Salvadori (1995, Chapter 14); Schefold (1997, Chapter 18).20Cf. Steedman (1989, Chapter 8) on Jevons; Steedman (1992) on Wicksteed.21Cf. Solow (1963, 1967) and Pasinetti (1969); for the discussion which followedPasinetti’s critiques, cf. then Solow (1970) and Pasinetti (1970); Dougherty (1972)and Pasinetti (1972).22Cf. for example the readings edited by Steedman (1977b, 1979a) and Steedman(1979b).Critique of the Marginalist Approach 111In addition, various commonplaces in marginalist theory came infor criticism from Steedman with reference to the theory of consumers’choice, the theory of technical progress and the theory of fiscal incidence.23 We may then recall the critiques of the ‘neoclassical synthesis’,and specifically of Modigliani’s (1944, 1963) attempt to set up a theoryof aggregate income and employment retaining the basic principlesof the marginalist tradition, while opening the door to the use ofKeynesian fiscal and monetary policies. 24 Another aspect of the ‘neoclassicalsynthesis’, and more generally of mainstream macroeconomictheory – the assumption of a ‘representative agent’, a trick that can beconsidered the other face of the choice of single-commodity models – iscriticised in various works by Lippi and others. 25Clearly, the criticism of the marginalist tradition generated by Sraffa’swork achieved highly significant results on a much wider front than isoften recognised. The marginalist theoreticians were then driven intoconcentrating their efforts in three fields. Firstly, we have intertemporalor temporary general equilibrium models, so general 26 as to prove sterileas guidance in interpretation of economic reality: any event can berationalised ex post, within these models, by assigning a particular setof values to the parameters, or by assuming opportune changes in theseparameters. Secondly, we have disequilibrium models, requiring ad hocassumptions on the adjustment mechanisms in order to obtain definiteresults, and which often use an aggregate notion of capital. Finally,especially in the field of macroeconomics, both the theoretical debate 27and most textbooks have fallen back on one-commodity models (withthe misleading use of the label of general economic equilibrium modelsas soon as more than one single period is considered, as in overlappinggenerations models), conveniently forgetting the results of the capitaltheory debates recalled above, though never attempting to deny thevalidity of those critiques.23Cf. respectively Steedman (1989, Chapter 11; 1985a; 1985b). Deep-reachingcritiques of the theory of consumer’s choice are also formulated by Parrinello(1982a).24These critiques, hinted at in Garegnani (1964–5), are developed in Roncagliaand Tonveronachi (1978, 1985), and in Roncaglia (1988).25Cf. for example Forni and Lippi (1997).26Notwithstanding the adoption of highly restrictive assumptions, such as thatof convexity (namely, decreasing returns) both in production and in consumption,as already recalled above.27To give just two examples, the theory of real business cycles, or to the so-called‘new growth theory’.