 For Wittgenstein, there simply is no distinction between syntax and semantics in mathematics: everything is syntax. If we wish to demarcate between “mathematical propositions” versus “mathematical pseudo-propositions”, as we do, then the only way to ensure that there is no such thing as a meaningful, but undecidable (e.g., independent), proposition of a given calculus is to stipulate that an expression is only a meaningful proposition in a given calculus (PR §153) if either it has been decided or we know of an applicable decision procedure. In this manner, Wittgenstein defines both a mathematical calculus and a mathematical proposition in epistemic terms. A calculus is defined in terms of stipulations (PR §202; PG 369), known rules of operation, and known decision procedures, and an expression is only a mathematical proposition in a given calculus (PR §155), and only if that calculus contains (PG 379) a known (and applicable) decision procedure, for “you cannot have a logical plan of search for a sense you don’t know” (PR §148).