Here we can see the beginning of two lifelong interests of Frege, namely, (1) in how concepts and definitions developed for one domain fare when applied in a wider domain, and (2) in the contrast between legitimate appeals to intuition in geometry and illegitimate appeals to intuition in the development of pure number theory. Indeed, some recent scholars have (a) shown how Frege’s work in logic was informed in part by his understanding of the analogies and disanalogies between geometry and number theory (Wilson 1992), and (b) shown that Frege was intimately familiar with the division among late 19th century mathematicians doing complex analysis who split over whether it is better to use the analytic methods of Weierstrass or the intuitive geometric methods of Riemann (Tappenden 2006). Weierstrass’s 1872 paper, describing a real-valued function that is continuous everywhere but differentiable   nowhere,[4]  was well known and provided an example of an ungraphable functions that places limits on intuition. Yet, at the same time, Frege clearly accepted Riemann’s practice and methods derived from taking functions as fundamental, as opposed to Weierstrass’s focus on functions that can be represented or analyzed in terms of other mathematical objects (e.g., complex power series).