W. V. O. Quine argued, notoriously and persuasively, that it is meaningless to quantify into opaque contexts (see, for instance, Quine 1943, 1953, 1956). I will refer to this claim as "Quine's Thesis". The idea is this. Suppose that C is any sentential context containing an occurrence of a singular term such that substitution of co-referential singular terms (SUB) is an invalid mode of inference with respect to this occurrence. Thus, in Quine's terminology, C is an "opaque" context. Now let C* result from C by substituting a variable v for the term at the relevant opaque occurrence. Then Quine's Thesis says that binding of this occurrence of v by a quantifier outside the scope of C* results in a meaningless expression.