Introduction

When it was originally written, the goal of this chapter was to construct a small part of what has been called a bio-legal history of contractual promises and their laws. However, such an enterprise necessarily entails prior reflection on how best to go about such an attempt to construct these bio-legal histories. Indeed, I mainly hoped, and still do, to show why evolutionary analysis in law, as well as its legal philosophical counterparts, could benefit considerably from incorporating culture – and its accompanying evolutionary theory – more explicitly into its models than seems to be the case at present. This should allow me to contrast my approach with some of the views expressed in Wojciech Załuski's recent book on Evolutionary Theory and Legal Philosophy, addressing questions lying at the heart of what could become an “evolutionary current in legal philosophy.”

To this end, I will draw on the legal example of equality in exchange in contract law on the one hand and on recent research on human cooperative behaviour on the other. I will start by making some remarks on the issue of substantive fairness in legal contract theory and in legal anthropology (Section II). I will then briefly sketch some results of experiments commonly used in behavioural economics to shed light on human pro-social behaviour (Section III).