 Erik Curiel (2001) has argued against the manner in which the ability to derive the Bekenstein-Hawking result as a theorem of an approach is used as evidence for that approach in much the same way that empirical evidence is used to justify a theory in normal circumstances, say predicting the value of a well-confirmed experimental result. It is true that black hole physics is used as testing ground for quantum gravity and the Bekenstein-Hawking result does not have the status of an empirical fact. However, it is a strong deduction from a framework that is fairly mature, namely quantum field theory on a curved spacetime background. In this sense, although it does not provide a constraint as strong as an experimentally observed phenomenon, it might legitimately function as a constraint on possible theories. Constraints on theory construction come in a variety of shapes and sizes, and not all take the form of empirical data — thought experiments are a case in point. In the context of quantum gravity it is especially important that one have some agreed upon constraints to guide the construction. Without them, work would halt. It also seems reasonable to insist that a full theory of quantum gravity be able to reproduce predictions of the semi-classical theory of gravity, since this will be one of its possible limits. Still, Curiel is right that researchers ought to be rather more wary of attributing too much evidential weight to such features that remain empirically unconfirmed.