人大经济论坛

 找回密码
 立即注册

QQ登录

只需一步,快速开始

搜索
热搜: 活动 交友 discuz
12
返回列表 发新帖
楼主: 布拉格之春

Adjusting the model to adjust the world

[复制链接]
 楼主| 发表于 2017-9-12 22:50:06 | 显示全部楼层
And it was Lange who took up the notion of the so-called ‘gradient system’ and re-interpreted it along the lines of the socialist planning. Gradient systems are a special type of the stability framework introduced by Samuelson in which the dynamics of a variable (in the case of general equilibrium stability theory – the price vector) can be interpreted as a gradient of a specific function (the ‘potential function’). Hands (1994 Hands, D. W. (1994). Restabilizing dynamics: Construction and constraint in the history of walrasian stability theory. Economics and Philosophy, 10, 243–283. 10.1017/S0266267100004740.
[Crossref], [Web of Science ®], [Google Scholar]
) showed that one of the reasons for Samuelson to abstain from using Liapunov-type dynamics in his earlier contributions to stability theory was that he was afraid of the normative implications inherent in such (otherwise technically very promising) enterprise:

Samuelson realized that if a Walrasian system is a gradient system… then the general equilibrium price vector p* must maximize some (potential) function. If this (potential) function is interpreted as social welfare or social utility, then the door is left open for a type of welfare economics with much stronger claims about the Pareto optimality of perfect competition than Samuelson wished to endorse. (Hands, 1994 Hands, D. W. (1994). Restabilizing dynamics: Construction and constraint in the history of walrasian stability theory. Economics and Philosophy, 10, 243–283. 10.1017/S0266267100004740.
[Crossref], [Web of Science ®], [Google Scholar]
, p. 263f.)

The logic of a gradient system is linked to the counter-intuitive and restrictive formalism of the symmetry of Jacobian matrix generated by the excess demand functions of the economy modeled. Such a symmetry ‘implies that the economy reduces to one big gradient system which maximizes something like an aggregate price potential’ (Hands, 1994 Hands, D. W. (1994). Restabilizing dynamics: Construction and constraint in the history of walrasian stability theory. Economics and Philosophy, 10, 243–283. 10.1017/S0266267100004740.
[Crossref], [Web of Science ®], [Google Scholar]
, p. 267). But although Samuelson, with all his inclinations toward social engineering, was nevertheless unwilling to follow this path, Lange quickly recognized the implications of this assumption and touched upon it in his 1944 book. Economy as a gradient system is amenable to manipulation on behalf of planning authorities because, roughly speaking, the effects of interaction between individual agents that could yield unexpected results (i.e., income effects in general equilibrium framework) vanish in such a system. As we have seen from the discussion of gradient methods, seeing economy as one big agent was a good opportunity to apply the gradient methods known from optimization theory to the general equilibrium model as a model of coordination. In some way, it amounted to assuming the coordination away.
 楼主| 发表于 2017-9-12 22:50:26 | 显示全部楼层
Lange (1936 Lange, O. (1936). On the economic theory of socialism: Part one. The Review of Economic Studies, 4, 53–71. 10.2307/2967660.
[Crossref], [Google Scholar]
) provided the simplest version of the decentralization procedure. But there was another, linear version available that became the starting point for the economists who tried to reconcile the planning vision of market socialists with the theory of economic equilibrium that required decentralization and coordination of heterogeneous interests. This updated version of planning and implementation was provided by Koopmans (1951 Koopmans, T. C. (1951). Analysis of production as an efficient combination of activities. In T. C.Koopmans (Ed.), Activity analysis of production and allocation (pp. 33–97). New York, NY: Wiley.
[Google Scholar]
).1414. As Robert Dorfman (1984 Dorfman, R. (1984). The discovery of linear programming. Annals of the History of Computing, 6, 283–295.
[Crossref], [Google Scholar]
, p. 294, cited in Backhouse, 2012 Backhouse, R. E. (2012). Paul Samuelson, RAND and the Cowles Commission activity analysis conference, 1947–1949. Unpublished working paper.
[Google Scholar]
, p. 24) recollects, Koopmans perceived clearly that an entire economy could be thought of as solving a vast linear programming problem in which the prices that emerged from competitive markets played the same role as the dual variables in Dantzig's theory of linear programming. This implied that the theory of linear programming could serve as a basis for rigorous formulation of the theory of general economic equilibrium.
View all notes

In the end of his classical paper on a linear model of production1515. The paper documented Koopmans' talk at the famous conference on the activity analysis held in 1949. On this conference, see Backhouse (2012 Backhouse, R. E. (2012). Paul Samuelson, RAND and the Cowles Commission activity analysis conference, 1947–1949. Unpublished working paper.
[Google Scholar]
), its importance for the development of general equilibrium theory is acknowledged both by Debreu (1959 Debreu, G. (1959). Theory of value: An axiomatic analysis of economic equilibrium. New York, NY: Wiley.
[Google Scholar]
) and by Arrow and Hahn (1971 Arrow, K. J., & Hahn, F. (1971). General competitive analysis. San Francisco, CA: Holden-Day.
[Google Scholar]
) and elucidated in detail by Düppe and Weintraub (2014a Düppe, T., & Weintraub, E. R. (2014a). Siting the new economic science: The Cowles Commission's activity analysis conference of June 1949. Science in Context, 27, 453–483.
[Crossref], [Web of Science ®], [Google Scholar]
, 2014b Düppe, T., & Weintraub, E. R. (2014b). Finding equilibrium. Arrow, Debreu, McKenzie and the problem of scientific credit. Princeton, NJ and Oxford: Princeton University Press.
[Crossref], [Google Scholar]
).
View all notes
Koopmans (1951 Koopmans, T. C. (1951). Analysis of production as an efficient combination of activities. In T. C.Koopmans (Ed.), Activity analysis of production and allocation (pp. 33–97). New York, NY: Wiley.
[Google Scholar]
, p. 93) elaborates on ‘the institutional arrangements under which decisions about the components of activity vector x are arrived at’. The ‘centralized decision-making agency’ could use the information of the matrix of production coefficients and choose a corresponding activity vector that could yield optimal results. But Koopmans also considers an opposite case where the decentralized decision-making takes place, i.e., where the activity levels are determined locally by those who are aware of a corresponding matrix column only. Koopmans concretizes this institutional logic by distributing the managing responsibilities among the helmsman (a curious name for the Lange's Central Planning Board, inadvertently reminding of Mao, especially in 1949) who chooses and announces the prices of final commodities; custodians for primary, intermediary, and final commodities who mimic the market by adjusting the prices in the direction of the excess demand; and managers of productive activities who command the production process by neglecting the activities of negative profitability, keeping those with zero profitability unchanged and enlarging those with positive profitability by issuing respective orders to the custodians. As Koopmans himself admits, these intricate rules (yielding, quite tautologically, in the manner of result-generating proposition, the necessary optimality in a static sense) just redescribe the working of a competitive system. The simple rules formulated for helmsman (actually representing a single ‘consumer’), custodians, and managers ‘suggest methods whereby a planned economy can strive for efficient allocation of resources in production’ or, in a decentralized economy, ‘help in the appraisal of alternative forms of economic organization or of market behavior from the point of view of efficiency’ (Koopmans, 1951 Koopmans, T. C. (1951). Analysis of production as an efficient combination of activities. In T. C.Koopmans (Ed.), Activity analysis of production and allocation (pp. 33–97). New York, NY: Wiley.
[Google Scholar]
, p. 95). The firm as such may also be regarded as a small planned economy and governed accordingly.

Koopmans consciously abstracted from the dynamic properties of these rules. In other words, he abstained from the studies of adjustment processes and, in particular, from investigating the stability of tatonnement. It was Samuelson (1949 Samuelson, P. A. (1949). Market mechanisms and maximization. The RAND Corp., Santa Monica. Repr. In J. E.Stiglitz (Ed.), The collected scientific papers of P.A. Samuelson (Vol. 1, pp. 425–492). Cambridge, MA: MIT Press.
[Google Scholar]
) who reformulated them (again, referring to the familiar idea of prices moving in the direction of excess demand) in the language of differential equations and derived non-convergence – the system was oscillating as a frictionless pendulum (Hurwicz, 1973 Hurwicz, L. (1973). The design of mechanisms for resource allocation. American Economic Review, 63, 1–30.
[Web of Science ®], [Google Scholar]
). Interestingly, Samuelson's idea was to use economic intuition of how markets work in order to derive solutions of dynamic resource allocation problems (Backhouse, 2012 Backhouse, R. E. (2012). Paul Samuelson, RAND and the Cowles Commission activity analysis conference, 1947–1949. Unpublished working paper.
[Google Scholar]
).1616. The general consensus unifying Koopmans, Lange, Lerner, Samuelson, and others was thus the particular understanding of market (demand) mechanisms as a key to the problems of resource allocation and the importance of technical calculative procedures for arriving at concrete solutions to these problems. However, important as this complex back-and-forth movement between the study of market mechanisms and normative planning ideas might seem, the very idea of what ‘the market’ is was, for the most GE theorists at that time, rather abstract and meager, hardly moving beyond the adjustment ideas developed in stability literature we referred to. On the lack of more sophisticated accounts of market mechanisms, see Mirowski (2002 Mirowski, Ph. (2002). Machine dreams: Economics becomes cyborg science. New York, NY: Cambridge University Press.
[Google Scholar]
).
View all notes
Arrow and Hurwicz (1960b Arrow, K. J., & Hurwicz, L. (1960b). Decentralization and computation in resource allocation. In R.Pfouts (Ed.), Essays in economics and econometrics (pp. 34–104). Chapel Hill, NC: University of North Carolina Press.
[Google Scholar]
) modify Koopmans's rules and finally derive convergence for the strictly concave economy.

However, Arrow and Hurwicz are mostly referred to in the context of their joint papers on stability theory. Along with trying to improve the working of a linear planning system suggested by Koopmans they did the same with the respect to the general equilibrium model looking for the constructive mechanisms to implement the results of the perfect competition.
 楼主| 发表于 2017-9-12 22:50:41 | 显示全部楼层
Hurwicz, stability, and mechanism design

Ingrao and Israel (1990 Ingrao, B., & Israel, G. (1990). Invisible hand.: Economic equilibrium in the history of science. Cambridge, MA: The MIT Press.
[Google Scholar]
) claim that historically the same group of ‘utopically’ oriented economists also considered the questions of stability to be redundant, which is only partly true. The most important economist who, one the one hand, was strongly influenced by the ‘utopian-normative’ approach (both relating to the issue of stability and with respect to economic theory in general) and, on the other, made a significant contribution to the theory of stability, was Leonid Hurwicz.

Born in Moscow in the year of the Russian revolution, Hurwicz was always intimately connected to the culture of socialism, be it in half-authoritarian Poland of the 1930s where he studied law, in London and Geneva where he got acquainted to the major critics of market socialism Hayek and Mises, or in the USA, where he was assistant to Lange. A member of the Cowles commission, Hurwicz, was fully initiated into the problems discussed there.

From the standpoint of our discussion Hurwicz is quite a remarkable figure. He received 2007 Nobel prize ‘for having laid the foundations of mechanism design theory,’ in particular for developing a concept of incentive compatibility in the 1970s. Mechanism design theory, as Hurwicz (1973 Hurwicz, L. (1973). The design of mechanisms for resource allocation. American Economic Review, 63, 1–30.
[Web of Science ®], [Google Scholar]
, p. 1) himself put it, ‘refuses to accept the institutional status quo of a particular time and place as the only legitimate object of interest and yet recognizes constraints that disqualify naïve utopias’. The program formulated by Hurwicz in the 1970s thus included both the constructivist idea of going beyond the existing institutional framework by devising new institutions and an attempt to overcome an abstract utopian (socialist!) ideal of creating a perfect society.

Hurwicz gained reputation in general equilibrium theory after publishing his results on equilibrium stability together with Arrow and with the collaboration of a mathematician H. D. Block (Arrow, Block, & Hurwicz, 1959 Arrow, K. J., Block, H. D., & Hurwicz, L. (1959). On the stability of the competitive equilibrium, II. Econometrica, 27, 82–109.
[Crossref], [Web of Science ®], [Google Scholar]
; Arrow & Hurwicz, 1958 Arrow, K. J., & Hurwicz, L. (1958). On the stability of the competitive equilibrium, I. Econometrica, 26, 522–552.
[Crossref], [Web of Science ®], [Google Scholar]
).1717. Arrow, another major progenitor of contemporary general equilibrium theory, was also an adherent of planning. In one of the latest autobiographical texts (Arrow, 2009 Arrow, K. (2009). Some developments in economic theory since 1940: An eyewitness account. Annual Review of Economics, 1, 1–16. 10.1146/annurev.economics.050708.143405.
[Crossref], [Web of Science ®], [Google Scholar]
), he concedes that the idea of planning was important for him at that time, albeit making certain reservations and claiming that, in fact, despite an enormous influence of Lange and Lerner (and – we would add – Arrow's advisor Harold Hotelling) along with equally enormous amount of intellectual energy spent, socialist ideas and models of planning had little influence on real economic situation. In an unpublished interview taken by our research group in April 2012, Arrow added to the skepticism toward his own socialist past the idea that in the general equilibrium theory he was just developing Hicks who had nothing to do with socialist concerns. However, he also recalled Frederick Taylor's (1929 Taylor, F. M. (1929). The guidance of production in a socialist state. American Economic Review, 19, 1–8.
[Google Scholar]
) presidential address to the American economic association dealing with the optimal running of socialist economy. Moreover, Hicks was the main reference in stability theory. The ambiguity thus remains, and we could still argue that in 1940–1960s Arrow not only knew about socialist and constructivist interpretations of the general equilibrium model, but also actively participated in its development along these lines. More on that in Mirowski (2002 Mirowski, Ph. (2002). Machine dreams: Economics becomes cyborg science. New York, NY: Cambridge University Press.
[Google Scholar]
, p. 298f.) and Klein (2013 Klein, D. B. (2013). Kenneth J. Arrow [Ideological profiles of the economics laureates]. Econ Journal Watch, 10, 268–281.
[Google Scholar]
).
View all notes
The two papers Arrow and Hurwicz produced were overtly inconclusive and positively biased: they admitted taking notice only of some cases, but in all of them equilibrium achieved by the tatonnement process was proved to be globally stable (meaning that the system converges to it from any point, and not just from its neighborhood). Even more important in our context is the idea of the system stability different from the equilibrium stability dealt with before. This generalization is justified on purely conceptual terms: ‘When there are two or more equilibria, it cannot be the case that all equilibrium points are globally stable’ (Arrow & Hurwicz, 1958 Arrow, K. J., & Hurwicz, L. (1958). On the stability of the competitive equilibrium, I. Econometrica, 26, 522–552.
[Crossref], [Web of Science ®], [Google Scholar]
, p. 524, cf. Feiwel, 1987 Feiwel, G. (Ed.). (1987). Arrow and the ascent of modern economic theory. Houndmills: Macmillan.
[Crossref], [Google Scholar]
, p. 263). But even if some equilibria are unstable, the cases considered suggested global stability of the whole edifice that gave hope for its relevance and even a certain degree of realisticness.

However, that was not the case. As Hurwicz' colleague Scarf's (1960 Scarf, H. (1960). Some examples of global instability of the competitive equilibrium. International Economic Review, 1, 157–172. 10.2307/2556215.
[Crossref], [Web of Science ®], [Google Scholar]
) and Gale's (1963 Gale, D. (1963). A note on global instability of competitive equilibrium. Naval Research Logistics Quarterly, 10, 81–87. 10.1002/nav.3800100107.
[Crossref], [Google Scholar]
) examples showed, no general result on the stability of the tatonnement can be established. In general, it turned out that for the tatonnement to be globally stable market excess demand functions should conform to the weak axiom of revealed preferences – ‘a property that is very special indeed’ (Fisher, 2011 Fisher, F. (2011). The stability of general equilibrium: What do we know and why is it important? In P.Bridel (Ed.), General equilibrium analysis: A century after Walras (pp. 34–45). London: Routledge.
[Google Scholar]
, p. 37). However, at least it gave an idea of how a stable economy, representational issues put aside, should look like – or, we would add, should be made to look like.

The latter was precisely the response of Hurwicz! His idea was to experiment with various models in order to construct, design an economic system that would be on the whole stable (cf. Feiwel, 1987 Feiwel, G. (Ed.). (1987). Arrow and the ascent of modern economic theory. Houndmills: Macmillan.
[Crossref], [Google Scholar]
, p. 262).1818. Interestingly, the notorious normative problem of Walrasian tatonnement – the question of who changes the prices – is circumvented here. The issue is, rather, whether the process as such, guided by the social planner or market forces, is stable.
View all notes
He concedes that Scarf's and Gale's examples somehow discouraged him:

[O]nce it was noted that there can be instabilities, this opened the question whether one could think of alternative stable mechanisms that one could consider either from a normative, descriptive, or computational point of view. (Feiwel, 1987 Feiwel, G. (Ed.). (1987). Arrow and the ascent of modern economic theory. Houndmills: Macmillan.
[Crossref], [Google Scholar]
, p. 268)

What is given here is a particularly instructive classification. A descriptive point of view invoked by Hurwicz implies the process of finding a model that would adequately capture the functioning of a real economy. A computational point of view is characteristic for some mathematical economists that were mostly interested in constructing a viable algorithm for computing equilibrium prices. The best example of such research is the work of Scarf (1973 Scarf, H. E. (1973). The computation of economic equilibria(with the collaboration of T. Hansen). Cowles Monograph No. 24. New Haven, CT and London: Yale University Press.
[Google Scholar]
). It is of particular interest for our story that even Scarf's negative results on stability were a part of this computational programme: as Scarf (1991 Scarf, H. (1991). The origins of fixed point methods. In J. K.Lenstra, A. H. G.Rinnooy Kan, & A.Schrijver (Eds.), History of mathematical programming. A collection of personal reminiscences. Amsterdam: North-Holland.
[Google Scholar]
) himself noted, his interest in finding counter-examples of tatonnement stability were guided by a conjecture that this Walrasian idea is in fact algorithmically viable and hence, can be computationally effective. If a general equilibrium model together with tatonnement were globally stable one could hope for a constructive solution of an equilibrium problem, i.e., of computing equilibria referring simply to the respective excess demands. But this hope was not realized.
 楼主| 发表于 2017-9-12 22:50:54 | 显示全部楼层
Hurwicz explicitly states that the problem of stability attracted him not only on theoretical grounds:

Imagine that you have centralized economy that operates by collecting information, computing what should be done, and then issuing commands. (This is an idealized version of a planned economy.)… How do you solve the problem of optimization centrally, supposing that you even have all the data?… [M]ost problems… can only be solved by some iterative method… But an iterative process of computation would be of no interest unless it has a tendency to converge to the correct answer. But what is a convergence if not stability of the iterative process? (Feiwel, 1987 Feiwel, G. (Ed.). (1987). Arrow and the ascent of modern economic theory. Houndmills: Macmillan.
[Crossref], [Google Scholar]
, pp. 260–261)

In the interview, Hurwicz claims that while designing a stable system converging to equilibrium is a normative and often a computational task, ‘the study of stability of the competitive system may be viewed as a first step in understanding the working of actual economies’ (Feiwel, 1987 Feiwel, G. (Ed.). (1987). Arrow and the ascent of modern economic theory. Houndmills: Macmillan.
[Crossref], [Google Scholar]
, p. 262). We posit that historically this was not true. The whole program of studying the tatonnement stability was normatively motivated, and it was not a coincidence that such a normatively oriented scholar as Hurwicz contributed most to stability theory.
We see that the theoretical problem of stability was reformulated and along with studying the properties of equilibrium came to be regarded as a problem of its implementation. The very word ‘mechanism’ suggests this technological meaning: a mechanism is intentional, it involves not only a description of a problem, but also (as ‘a mechanism of’) an indication of the ways to realize some goals. Hurwicz, in particular, was concerned with the mechanisms of resource allocation that, following Robbins' definition, could be characterized as economic mechanism par excellence. Stability analysis can thus be regarded as the major self-implementing technology of the ADM model.
 楼主| 发表于 2017-9-12 22:51:07 | 显示全部楼层
Why bother? Constructive mechanisms at work

The preceding discussion was framed along some particular historical narrative. It showed that constructive mechanisms were, in fact, always present and accompanied economic model-building in the postwar neoclassical theory. Almost all of the general equilibrium (GE) theorists we referred to did not claim to be descriptively accurate and thus to build their models as representations. Rather, they sought to endow them with additional calculative techniques that would be instrumental in finding/arriving at an optimal solution or equilibrium. One is left wondering whether this story is still relevant today. Although we are not able to give a conclusive answer, we can reasonably conjecture that for contemporary economists these issues are no less vital than they were for the members of the postwar Cowles commission.

Mechanism design, a field initiated by our major protagonist, Hurwicz, has become a theoretical foothold for many important developments in the postwar economics. Indeed, at its inception, it was deeply connected to the studies of adjustment processes by Hurwicz, Arrow, and their collaborators and further, after the disappointing results in general equilibrium theory, became a refuge for many its adherents (although not without the related difficulties that make the picture not so rosy as it might seem, cf. Lee, 2006 Lee, K. S. (2006). Mechanism design theory embodying an algorithm-centered vision of markets/organizations/institutions. History of Political Economy, 38(Suppl. 1), 283–304. 10.1215/00182702-2005-026.
[Crossref], [Web of Science ®], [Google Scholar]
). After realizing further limitations of the adjustment processes linked mainly to the information asymmetries (Makowski & Ostroy, 1993 Makowski, L., & Ostroy, J. M. (1993). General equilibrium and market socialism: Clarifying the logic of competitive markets. In P. K. BardhanBardhan & J. E.Roemer (Eds.), Market socialism: The current debate (pp. 69–88). New York, NY: Oxford University Press.
[Google Scholar]
, 2001 Makowski, L., & Ostroy, J. M. (2001). Perfect competition and the creativity of the market. Journal of Economic Literature, 39, 479–535. 10.1257/jel.39.2.479.
[Crossref], [Web of Science ®], [Google Scholar]
), mechanism design theorists, armed with Hurwicz's notion of incentive compatibility, started to work on the ways to redesign the incentive structures so that to motivate economic agents to reveal their private information to the social planner/market regulator in order to establish optimal mechanisms. Planning became more local, but the principles of mechanism design – to construct social institutions with some desired properties, be it new markets or auction rules (Roth, 2002 Roth, A. (2002). The economist as engineer: Game theory, experimentation, and computation as tools for design economics. Econometrica, 70, 1341–1378. 10.1111/1468-0262.00335.
[Crossref], [Web of Science ®], [Google Scholar]
) – remained the same. Mechanism design theorists joined their efforts with experimental economists1919. Albeit not without tension due to the differences in their epistemic cultures, on which we cannot elaborate further here, see Mirowski & Nik-Khah, 2008 Mirowski, Ph., & Nik-Khah, E. (2008). Command performance: Exploring what STS thinks it takes to build a market. In T.Pinch & R.Swedberg (Eds.), Living in a material world: Economic sociology meets science and technology studies (pp. 89–128). Cambridge, MA: MIT Press.
[Google Scholar]
. However, historical studies do suggest that the two communities shared a common research agenda and maintained strong ties – both conceptual and institutional (Lee, 2013 Lee, K. S. (2013). What mechanism design theorists had to say about laboratory experimentation in the mid-1980s. Center for the History of Political Economy Working Paper No. 2013–18. Retrieved from
http://hope.econ.duke.edu/node/897
.
[Google Scholar]
).
View all notes
who, on their part, are moving from the mere explanatory work of testing the principles of rational choice and game-theoretic propositions in the laboratory to actively creating the rules for the new markets and auctions as ‘economic machines’ (Guala, 2001 Guala, F. (2001). Building economic machines: The FCC auctions. Studies in History and Philosophy of Science, 32, 453–477. 10.1016/S0039-3681(01)00008-5.
[Crossref], [Web of Science ®], [Google Scholar]
, 2007 Guala, F. (2007). How to do things with experimental economics. In D.MacKenzie, F.Muniesa, & L.Siu (Eds.), Do economists make markets? On the performativity of economics (pp. 128–162). Princeton, NJ: Princeton University Press.
[Google Scholar]
). Behavioral economists in their attempts to ‘nudge’ (Thaler & Sunstein 2008 Thaler, R. H., & Sunstein, C. R. (2008). Nudge. Improving decisions about health, wealth, and happiness. New Haven, CT: Yale University Press.
[Google Scholar]
) human decisions in order to make economic agents more rational are also, in fact, indirectly trying to provide certain implementation technologies for various well-known economic models and to produce homo oeconomicus apart from merely registering the deviations from the model of rational choice. In other words, the theory of rational choice becomes normative (Hands, 2011 Hands, D. W (2011). Normative rational choice theory: Past, present, and future. Retrieved from
http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1738671
.
[Google Scholar]
) and as such in need of implementation. A recent paper summarizing a growing body of literature on social preferences invokes a ‘sophisticated social planner’ who pays attention not only to the egoistic motivations in providing an incentive structure, but also takes account of the other-regarding preferences and other value issues (Bowles & Polanía-Reyes, 2012 Bowles, S., & Polanía-Reyes, S. (2012). Economic incentives and social preferences: substitutes or complements?Journal of Economic Literature, 50, 368–425. 10.1257/jel.50.2.368.
[Crossref], [Web of Science ®], [Google Scholar]
).

On the other part of theoretical spectrum, in the new institutional economics, development economics, and economic history, the similar tendencies are discernible. A nice example would be the recent work of Douglass North and his collaborators (North, Wallis, & Webb, 2009 North, D. C., Wallis, J. J., & Weingast, B. R. (2009). Violence and social orders. Cambridge: Cambridge University Press.
[Crossref], [Google Scholar]
, 2012 North, D. C., Wallis, J. J., & Webb, S. B. (Eds.). (2012). In the shadow of violence. Politics, economics, and the problems of development. Cambridge: Cambridge University Press.
[Crossref], [Google Scholar]
) on violence and ‘limited access orders’. An important argument emerging in this literature considers the limitation of violence as an institutional key to achieving the desired rates of economic growth and the path of the successful economic development. To limit the violence one needs, in fact, to find an incentive structure that could make execution of violence disadvantageous for the most of the interest groups and powers in a given country. Although their analysis is, admittedly, descriptive, what they try to arrive at are lessons from history and proposal for institutional design governed by the same intellectual patterns as those we discussed above, i.e., quite germane to what mechanism design theory proposed on the micro-level.
 楼主| 发表于 2017-9-12 22:51:18 | 显示全部楼层
In sum, the self-implementing technologies are still around in various versions of economic model-building. It does not mean, of course, that they are ubiquitous, but we can reasonably argue that the practices of doing economics today are shaped in various ways by the attempts to construct not just a coherent theoretical narrative, but also to ensure its realization and to implant these constructive mechanisms into the models.
 楼主| 发表于 2017-9-12 22:51:31 | 显示全部楼层
Conclusion

Philosophers of economics are most often preoccupied with the validity of economic models. In general, this implies finding out what kind of model could be called a successful representation and rationalizing the ways unrealistic models with assumptions lacking empirical support may still be relevant for various practical purposes, be it the explanation of real-world phenomena or policy considerations. Our approach proposes a different direction. Once it is recognized that, apart from being a representation, a model may also be considered as an instrument of social engineering, the plurality of links between model and reality emerges. Epistemological issues of resemblance should then be supplemented by the ways economists furnish (often unrealistic) models with various constructive mechanisms aimed at enacting the optimal solutions described by the model. If a model contains an explicit proposal to redesign its target, this has important implications for all sorts of problems tackled in philosophy of economic modeling, ranging from the issues of the models' realisticness to assessing the explanatory value of modeling.

It is not that we have to abandon the representational issues altogether. First, even if we were to realize the proposed transformation of reality along the lines of a given model, the viability of this enacting process would obviously reveal a representation-based analysis. Second, we certainly do not claim that any economic model is built in order to be implemented in reality. Our argument, rather, calls for complementing the problems of valid explanations and predictions with the consideration of constructive mechanisms, or self-implementing technologies. In fact, as we have seen, they matter both for the content of economic theories and for their development. However, throughout the text, we tried to consciously abstain from dealing with the question of how successful this implementation might be or was in reality. Rather, our aim is to better understand the internal structure and functions of existing economic models, as well as the possible motivations of economists building them.

ADM model, an implausible way of describing the economy, drew its strengths and virtues not from the idea of a correct representation (its descriptive accuracy was hardly believed even by its creators), but from the idea of internal coherence and self-adjustment aimed at performing itself. Hurwicz' first constructive mechanism used in various models was a so-called ‘gradient method’ of finding equilibrium. He later used it in his joint work with Arrow on the stability of general equilibrium. One of the important motivations behind the stability theory and the parallel work on adjustment in the resource allocation processes was, in fact, to provide a plausible self-implementing technology for the Walrasian general equilibrium model (as the one that took most advantage from the decentralization).
 楼主| 发表于 2017-9-12 22:51:46 | 显示全部楼层
This might also imply that the models should be treated differently because their pragmatic value for the user might consist not only their representativeness but in producing the inferences to be easily implemented in reality. In fact, this might become a more plausible ‘story’ (Morgan, 2001 Morgan, M. S. (2001). Models, stories and the economic world. Journal of Economic Methodology, 8, 361–384. 10.1080/13501780110078972.
[Taylor & Francis Online], [Google Scholar]
) a model can tell. Hurwicz's stories of a social planner or mechanism designer, stories that were told almost parallel to the existence proof and accompanied the search of stability, became the important element of the ADM model and complemented its blatant lack of realistic descriptions. They show us that a model can be not just a neutral instrument of description, but may also contain a tool of changing the reality in order to bring it in line with the model. Hurwicz provided a response to the Hayek's challenge claiming that it is possible to design an optimal institutional setting ab ovo. He thus wanted both to rationalize the system's stability and to find the ways of stabilizing it thereby stabilizing the paradoxical beliefs in the harmony of general equilibrium. A ‘good’, but unrealistic theoretical picture, a normative utopia condensed in a model, so typical for economics, needs a constructive mechanism that accompanies model building in economics and gives economists hope to see their visions implemented in reality.
您需要登录后才可以回帖 登录 | 立即注册

本版积分规则

关于我们|Archiver|手机版|小黑屋|人大经济论坛 ( 京ICP备05066828号-20 京公网安备 11040202430141号 )

GMT+8, 2019-12-16 22:25 , Processed in 0.044742 second(s), 23 queries .

Powered by Discuz! X3.4

© 2001-2017 Comsenz Inc.

快速回复 返回顶部 返回列表