Private Law Theory

ABSTRACT
Does a general principle of good faith create too much uncertainty in Contract Law? This article provides in-depth consideration of the controversy around this question. Reviewing a number of common arguments and reasons why good faith is said to be too uncertain, and responses to these, the article finds a complex picture rather than a simple answer. Recent Canadian experience with recognising a general principle of good faith in contractual performance suggests that at least two further details are critical to the potential for uncertainty: first, whether good faith operates as a freestanding duty or instead functions as a unifying principle that animates and explains more specific obligations in specific contexts; and secondly, whether recourse to the general principle as a basis for challenging or reforming a recognised set of specific duties is readily available or more guarded to balance interests in stability and predictability with the law’s inevitable need to develop.

Marcus Moore, Good Faith and Certainty in Contract Law in Sustainability in Financial and Commercial Contracts (Maren Heidemann, Mads Andenas, Valerio Lemma and Catherine Pédamon eds, 2026).