MiltonFriedman实证经济学的方法论Word文档下载推荐.docx

1、mischievous errors and urges the importance of recognizing adistinct positive science of political economy.1This paper is concerned primarily with certain methodologicalproblems that arise in constructing the distinct positive scienceKeynes called for - in particular, the problem how to decide wheth

2、era suggested hypothesis or theory should be tentatively accepted aspart of the body of systematized knowledge concerning what is. Butthe confusion Keynes laments is still so rife and so much of ahindrance to the recognition that economics can be, and in part is, apositive science that it seems well

3、 to preface the main body of thepaper with a few remarks about the relation, between positive andnormative economics.1. THE RELATION BETWEEN POSITIVE AND NORMATIVEECONOMICSConfusion between positive and normative economics is to someextent inevitable. The subject matter of economics is regarded byal

4、most everyone as vitally important to himself and within the rangeof his own experience and competence; it is* I have incorporated bodily in this article without special referencemost of my brief Comment in A Survey of Contemporary Economics,Vol. II （B. F. Haley, ed.） （Chicago: Richard D. Irwin, Inc

5、., 1952）, pp.455-57.I am indebted to Dorothy S. Brady, Arthur F. Burns, and George J.Stigler for helpful comments and criticism.1. （London: Macmillan 4 Co., 1891）, pp. 34-35 and 46.34the source of continuous and extensive controversy and the occasionfor frequent legislation. Self-proclaimed experts

6、speak with manyvoices and can hardly all be regarded as disinterested; in any event,on questions that matter so much, expert opinion could hardly beaccepted solely on faith even if the were nearly unanimousand clearly disinterested.2The conclusions of positive economicsseem to be, and are, immediate

7、ly relevant to important normativeproblems, to questions of what ought to be done and how any givengoal can be attained. Laymen and experts alike are inevitablytempted to shape positive conclusions to fit strongly held normativepreconceptions and to reject positive conclusions if their normative,imp

8、lications - or what are said to be their normative implications -are unpalatable.Positive economics is in principle independent of any particularethical position or normative judgments. As Keynes says, it deals withwhat is, not with what ought to be. Its task is to provide a systemof generalizations

9、 that can be used to make correct predictions aboutthe consequences of any change in circumstances. Its performance isto be judged by the precision, scope, and conformity with experienceof the predictions it yields. In short, positive economics is, or can be,an objective science, in precisely the sa

10、me sense as any of thephysical sciences. Of course, the fact that economics deals with theinterrelations of human beings, and that the investigator is himselfpart of the subject matter being investigated in a more intimate sensethan in the physical sciences, raises special difficulties in achievingo

11、bjectivity at the same time that it provides the social scientist with aclass of data not available to the physical2. Social science or economics is by no means peculiar in this respect -witness the importance of personal beliefs and of home remedies inmedicine wherever obviously convincing evidence

12、 for opinion islacking. The current prestige and acceptance of the views of physicalscientists in their fields of specialization - and, all too often, in otherfields as well - derives, not from faith alone, but from the evidence oftheir works, the success of their predictions, and the dramaticachiev

13、ements from applying, their results. When economics seemed toprovide such evidence of its worth, in Great Britain in the first half of thenineteenth century, the prestige and acceptance of scientific economicsrivaled the current prestige of the physical sciences.5scientist. But neither the one nor t

14、he other is, in my view, a fundamentaldistinction between the two groups of sciences.3Normative economics and the art of economics, on the other hand,cannot be independent of positive economics. Any policy conclusionnecessarily rests on a prediction about the consequences of doing onething rather th

15、an another, a prediction that must be based - implicitlyor explicitly - on positive economics. There is not, of course, aone-to-one relation between policy conclusions and the conclusionsof positive economics; if there were, there would be no separatenormative science. Two individuals may agree on t

16、he consequencesof a particular piece of legislation. One may regard them as desirableon balance and so favor the legislation; the other, as undesirable andso oppose the legislation.I venture the judgment, however, that currently in the Westernworld, and especially in the United States, differences a

17、bouteconomic policy among disinterested citizens derive predominantlyfrom different predictions about the economic consequences of takingaction - differences that in principle can be eliminated by theprogress of positive economics - rather than from fundamentaldifferences in basic values, difference

18、s about which men canultimately only fight. An obvious and not unimportant example isminimum-wage legislation. Underneath the welter of argumentsoffered for and against such legislation there is an underlyingconsensus on the objective of achieving a living wage for all, to usethe ambiguous phrase so

19、 common in such discussions. The differenceof opinion is largely grounded on an implicit or explicit difference inpredictions about the efficacy of this particular means in furtheringthe agreed-on end. Proponents believe （predict） that legal minimumwages diminish poverty by raising the wages of thos

20、e receiving lessthan the minimum wage as well as of some receiving more than the3. The interaction between the observer and the process observed that isso prominent a feature of the social sciences, besides its more obviousparallel in the physical sciences, has a more subtle counterpart in theindete

21、rminacy principle arising out of the interaction between the processof measurement and the phenomena being measured. And both have acounterpart in pure logic in Godels theorem, asserting the impossibilityof a comprehensive self-contained logic. It is an open question whetherall three can be regarded

22、 as different formulations of an even moregeneral principle.6minimum wage without any counterbalancing increase in the numberof people entirely unemployed or employed less advantageously thanthey otherwise would be. Opponents believe （predict） that legalminimum wages increase poverty by increasing t

23、he number of peoplewho are unemployed or employed less advantageously and that thismore than offsets any favorable effect on the wages of those whoremain employed. Agreement about the economic consequences of thelegislation might not produce complete agreement about itsdesirability, for differences

24、might still remain about its political orsocial consequences; but, given agreement on objectives, it wouldcertainly go a long way toward producing consensus.Closely related differences in positive analysis underlie divergentviews about the appropriate role and place of trade-unions and thedesirabili

25、ty of direct price and wage controls and of tariffs. Differentpredictions about the importance of so-called economies of scaleaccount very largely for divergent views about the desirability ornecessity of detailed government regulation of industry and even ofsocialism rather than private enterprise.

26、 And this list could beextended indefinitely.4 Of course, my judgment that the majordifferences about economic policy in the Western world are of thiskind is itself a positive statement to be accepted or rejected on thebasis of empirical evidence.If this judgment is valid, it means that a consensus

27、on correcteconomic policy depends much less on the progress of normativeeconomics proper than, on the progress of a positive economicsyielding conclusions that are, and deserve to be, widely accepted. Itmeans also that a major reason for4. One rather more complex example is stabilization policy.Supe

28、rficially, divergent views on this question seem to reflect differencesin objectives; but I believe that this impression is misleading and that atbottom the different views reflect primarily different judgments about thesource of fluctuations in economic activity and the effect of alternativecounter

29、cyclical action. For one major positive consideration that accountsfor much of the divergence see The Effects of a Full-Employment Policyon Economic Stability: A Formal Analysis, infra, pp. 117-32. For asummary of the present state of professional views on this question seeThe Problem of Economic Instability, a report of a subcommittee of theCommittee on Public Issues of the American Economic Association,American Economic Review, XL （September, 1950）, 501-38.7distinguishing positive. economics sharply from normative economicsis precisely the contribution that can ther