 The 1906 “Foundations of Geometry” essay is primarily a re-statement of Frege’s earlier objections (discussed above) to Hilbert’s treatment of consistency and independence. After a rehearsal of those objections, Frege turns in Part iii to the problem of giving a positive method for proving independence. How, he asks, might one prove a given thought independent of a collection of thoughts? In answer, Frege provides a sketch of a potential method, and ends the discussion by noting that the method sketched is still incomplete, and that it faces some difficulties. Despite the obvious incompleteness, Frege never (as far as we can tell) returns to the proposal, and would seem in the end to have found it unsatisfactory. That he thought it unsatisfactory in principle is indicated by his claim four years later, in a note to Jourdain, that the unprovability of the parallels axiom cannot be proven (see Frege 1980: 183n). That is, he would seem by 1910 to hold that there is no systematic method for proving  independence.[11]