Precedent, we have seen, is inadequately accounted for by classical legal positivists. Part of the reason for this is that classical positivists wanted to explain the validity of laws. Validity, being a non-variable concept, is poorly suited to analyses of precedential authority. The idea of judges formulating decisions so that they might bind as a statute binds is not inconceivable. But it is simply not what common-law judges do. Lord Wright seemed to think differently when, writing during the era when the House of Lords considered itself bound by its own precedents, he observed that, if the House determines a principle on a particular set of facts then, should the materially same facts arise again, the earlier decision ‘is to be treated as if part of an Act of Parliament’. But according to Lord Reid, although judges will sometimes interpret earlier decisions of the House ‘as if they were provisions in an Act of Parliament’ – especially when the decision is composed of a single speech – such interpretations are never appropriate, for: