 More directly and explicitly, Dedekind’s essay was tied to the arithmetization of analysis in the nineteenth century—pursued by Cauchy, Bolzano, Weierstrass, and others—which in turn was a reaction to tensions within the differential and integral calculus, introduced earlier by Newton, Leibniz, and their followers (Jahnke 2003, chs. 3–6). As is well known, the inventors of the calculus relied on appeals to “infinitesimal” quantities, typically backed up by geometric or even mechanical considerations, although this was seen as questionable from early on. The nineteenth-century “arithmetizers” found a way to avoid infinitesimals (in terms of the epsilon-delta characterization of limits familiar from current introductions to the calculus). Yet this again, or even more, led to the need for a systematic characterization of various quantities conceived of as numerical entities, now in the form of a unified treatment of rational and irrational numbers.