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H.L.A. Hart and the Practical Difference Thesis

68 Pages Posted: 28 Nov 2003  

Kenneth Einar Himma

University of Washington - School of Law


In H.L.A. Hart's now famous Postscript to The Concept of Law, he embraced the Incorporation Thesis, according to which it is possible for a legal system to have a rule of recognition that incorporates moral criteria of validity. Scott Shapiro argues that the Incorporation Thesis is inconsistent with Hart's functionalist conception of law. On Hart's view, the essential function of law is to guide behavior. This implies, according to Shapiro, that every legal norm must be capable of guiding behavior. But Shapiro argues it is logically impossible for a judge to be guided simultaneously by an inclusive rule of recognition and by the rules validated under the rule. Thus, he concludes that Hart must give up either the Incorporation Thesis or his functionalist conception of law as providing guides to behavior.

In this essay, I will evaluate Shapiro's influential critique of the Incorporation Thesis. I will argue that Shapiro's argument succeeds, at most, against certain accounts of what it means to be guided by a rule. There are other plausible accounts of guidance that not only allow for inclusive rules of recognition, but also satisfy Shapiro's own standard for accounts of motivational guidance. Further, I will challenge two critical theoretical claims on which his argument rests, namely (1) that Hart's view implies a judge must be motivationally guided by the first-order legal norms she applies in deciding a case; and (2) that a commitment to legal functionalism implies the Practical Difference Thesis.

Keywords: Hart, Practical Difference Thesis, incorporationism, inclusive positivism, Scott Shapiro

Suggested Citation

Himma, Kenneth Einar, H.L.A. Hart and the Practical Difference Thesis. Legal Theory, Vol. 6, No. 1, pp. 1-43, March 2000. Available at SSRN:

Kenneth Einar Himma (Contact Author)

University of Washington - School of Law ( email )

William Gates Hall
Box 353020
Seattle, WA 98195-3020
United States
206-543-4550 (Phone)

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