 Instead of trying to begin with simple ideas and construct propositions from them, Bolzano works from the outside in, trying to distinguish parts within propositions, generally following what Quine called the “maxim of shallow analysis”, namely, “expose no more logical structure than seems useful for the deduction or other inquiry at hand” (Quine, 1960: §33; 160). Since propositions in themselves are causally inert, this cannot be done by inspecting them. Rather, one considers linguistic expressions, drawn from a variety of languages, along with one’s own thoughts, and attempts to identify features of logical significance, bearing in mind that “common usage does not aim at logical correctness but rather at brevity and sufficient distinctness.” (TS, §170 [II.213]; see also §350, 366).