 All the material needed for analysis, including both the rational and all the real numbers, can thus be constructed out of the natural numbers by set-theoretic means. At this point the question arises: Do we have to take the natural numbers themselves as given; or can anything further be said about those numbers, perhaps by reducing them to something even more fundamental? Many mathematicians in the nineteenth century were willing to assume the former. A well-known example is Leopold Kronecker, for whom the natural numbers are “given by God” while the rest of arithmetic and analysis is “made by mankind” (Ferreirós 1999, ch. 4). In contrast Dedekind, and independently Frege, pursued the latter option: they attempted to reduce arithmetic and the natural numbers to “logic”. This is the main goal of Was sind und was sollen die Zahlen? (The Nature and Meaning of Numbers, or more literally, What are the numbers and what are they for?). Another goal is to answer the related second sub-question above: whether more can be said about the set-theoretic procedures used. For Dedekind, again similar to Frege, those procedures are part of logic. Along the way, Dedekind also attempts to clarify his notion of creation. But then, what are the basic notions of logic?