Legal Positivism and the Rule of Law: The Hartian Response to Fuller's Challenge

This study analyses the way that legal positivists from HLA Hart onwards have responded to Lon L Fuller’s challenge to positivism from the idea of the rule of law. The main thesis is that Hart and contemporary legal positivists working in the Hartian tradition have yet to adequately respond to Fuller’s Challenge. I argue that the reason for this is the approach they take to dealing with Fuller’s principles of the rule of law, which either (i) proceeds on the basis of the positivist perspective without engaging with Fuller’s wider anti-positivist arguments, or else (ii) accepts Fuller’s claim that the rule of law is part of our concept of law but does not acknowledge any effect of this on what determines legal validity (the content of legal norms). In both cases, I argue that tensions and problems result from a lack of engagement with Fuller’s anti-positivism. On the one hand, positivists have failed to show why their account of the nature of law better reflects our understanding of law than Fuller’s. On the other, the concessions that positivists have made to Fuller’s arguments are often detached from other elements in their theories, raising the question of whether the positivist response to Fuller is coherent. In addition, by closely analysing the major positivist accounts of the rule of law, this study challenges a number of orthodox interpretations that confuse our understanding of the positivist response to Fuller. I show that most positivists accept that there is something morally valuable about a legal system’s conformity to the principles of the rule of law, and that there is always some kind of at least minimal conformity to those principles in any legal system. By noticing what concessions positivists have made to Fuller’s understanding of the rule of law, I aim to both (i) shift the debate to the remaining disputes with the Hartian positivists, particularly on issues such as the ‘derivative approach’ and the ‘validity Social thesis’, and (ii) identify areas of fruitful engagement with Fuller, such as the question of judges’ moral obligations to law.SJ