 The 1906 proposal itself can be outlined as follows. Suppose, says Frege, that we have a collection C of sentences each of which expresses a determinate thought, and a sentence S that similarly expresses a determinate thought. The heart of the proposed method for proving the independence of the S-thought from the C-thoughts is that we employ a mapping μ of terms to terms (and hence also of sentences to sentences) that preserves syntactic type (mapping names to names, one-place predicates to one-place predicates, etc.) and maps ’logical’ terms to themselves. Then: the S-thought is independent of the C-thoughts if μ maps S to a false sentence while mapping all the members of C to true sentences. (For discussion and development of Frege’s proposal, see Antonelli &amp; May 2000, Eder 2016. For discussion of Frege’s reasons for rejecting the proposal, see Ricketts 1997, Eder 2013, Blanchette 2014.) 