 Harman’s skepticism about the normativity of logic can thus be understood as skepticism as to whether a serviceable bridge principle is to be had. In order properly to adjudicate whether Harman’s skepticism is justified, we need to know what “the options are”. But how? John MacFarlane (MF2004) offers a helpful taxonomy of bridge principles which constitutes a very good first approximation of the range of options. This section briefly summarizes MacFarlane’s classification, as well as subsequent developments in the literature.