“… nor does it follow, in the case of a legal system such as ours, that a principle can be said to be truly a part of the law merely because it would be a more perfect expression of imperfect rules, which, though imperfect, are well established and well defined.”
“Formerly, it was the practice, where an action was brought for an agreed price … of work which was to be performed according to contract, to allow the plaintiff to recover the stipulated sum, leaving the defendant to a crossaction for breach of … contract … and this course was simple and consistent … But after the case of Basten v. Butter, 7 East 479 , a different practice … began to prevail, and being attended with much practical convenience, has been since generally followed; and the defendant is now permitted to show that … the work in consequence of the non-performance of the contract … [was] diminished in value … The same practice has not, however, extended to all cases of work and labour, as, for instance, … an action for freight; Sheels v. Davies, 4 Camp. 119.”