The question I set out to answer in my book is how to allocate authority in the modern administrative state. I first distinguish between epistemic deference and doctrinal deference. Perhaps the most popular means of characterising deference is to associate it with the giving of weight. I attach the label of epistemic deference to this notion. Focusing on epistemic deference, however, may cause one to overlook an equally important notion. Deference may also refer to the allocation of authority. Rather than simply paying respect to the decisions of another, one might allocate authority to another to make binding decisions. Such authority need not be absolute: its exercise might be subject to limitations of, to take a pertinent example, reasonableness. Decisions are binding, as long as they are, say, reasonable. I attach the label of doctrinal deference to this notion. I proceed to provide concrete examples of epistemic deference and doctrinal deference, drawing from American, Canadian and English jurisprudence.
I urge the adoption of a doctrine of what I call curial deference, to be applied by courts in the review of administrative action. However, the very idea of doctrinal deference has come under strong attack. I therefore respond to some of the more important criticisms. For example, I defeat TRS Allan's claim that any doctrine of deference is inevitably empty, by demonstrating that a doctrine can have effect independently of the context of any particular case, thereby precluding a court from reaching particular conclusions.
I conclude, in support of an approach based on doctrinal deference, that the prospect of judges reasoning explicitly and exclusively from constitutional principles is a troubling one. Judicial reliance on constitutional principles to the exclusion of doctrine carries with it the possibility of inconsistency and uncertainty. Troubling images uneven chancellors’ feet and of unruly horses accompany any argument that judges should reason directly from constitutional principles. One must also be aware, however, of the risk that empty principles, which obscure more than they reveal, might be labelled as doctrine. Those of us who advocate a doctrinal approach in public law should be cautious to ensure that our proposed doctrines are sufficiently hard-edged to function as useful tools in the hands of judges and practitioners toiling at the judicial review coalface.