Waddams argues that principle and policy, rather than being opposed, have been closely interrelated, each giving shape to the other.Stephen Waddams argues that it is an over-simplification to insist upon too sharp a distinction between the concepts of principle and policy in contract law. Each has incorporated elements of the other, enabling English contract law to change over time while maintaining a high degree of stability and predictability.Stephen Waddams argues that it is an over-simplification to insist upon too sharp a distinction between the concepts of principle and policy in contract law. Each has incorporated elements of the other, enabling English contract law to change over time while maintaining a high degree of stability and predictability.Although presented as being derived from the past, principles in contract law have been subject to constant reformulation, thereby facilitating legal change while simultaneously seeming to preclude it. Principle and policy have been mutually interdependent, propositions not usually being called principles unless they have been perceived to lead to just results in particular cases, and as likely to produce results in future cases that accord with common sense, commercial convenience and sound public policy. The influence of policy has been frequent in contract law, but Stephen Waddams argues that an unmediated appeal to non-legal sources of policy has been constrained by the need to formulate generalised propositions recognised as legal principles. This interrelation of principle and policy has played an important role in enabling an uncodified system to hold a middle course between a rigid formalism on the one hand and an unconstrained instrumentalism on the other.1. Introduction: empire of reason or republic of common sense?; 2. Intention, will, and agreement; 3. Promise, bargain, and consideration; 4. Unequal transactions; 5. Mistake; 6. Public policy; 7. Enforcement; 8. Conclusion: joint dominion of principle anl£²