 The second issue that divides Frege and Hilbert, regarding the justifiability of the inference from consistency to existence, is also still alive. While everybody (including presumably Hilbert) would agree with Frege that outside of the mathematical domain we cannot safely infer existence from consistency, the question remains whether we can (or must) do so within mathematics. The Fregean point of view is that the existence of mathematical objects can only be proven (if at all) by appeal to more fundamental principles, while the Hilbertian point of view is that in appropriate purely-mathematical cases, there is nothing more to be demonstrated, in order to establish existence, than the consistency of a theory (see entries on  philosophy of mathematics  and  Platonism in the philosophy of mathematics).  