Consideration and Estoppel: Problem and Panacea

In his book, The History of the Common Law of Contract, A.W.B. Simpson demonstrates that consideration originally seems to have meant the "matter of inducement" - the "why" of entering a promise.' He writes: "The essence of the doctrine of consideration, then, is the adoption by the common law of the idea that the legal effect of a promise should depend upon the factor or factors which motivated the promise. To decide whether a promise to do X is binding, you need to know why the promise was made."2 In modem terms, according to Simpson, a promise which lacks any adequate motive cannot have been serious and therefore ought not to be taken seriously. There could have been other reasons for enforcing a promise, such as induced reliance and detriment, but these reasons were subsumed into one test for the actionability of all promises: the requirement of good consideration. Consideration was simply a reason to enforce an obligation or a promise. It was a moral justification or legitimisation for enforcing an obligation: Why it was right that it should be enforced.