Michael Friedman (Stanford) gives a talk at the MCMP Workshop on Carnap titled "Carnap's Logico-Mathematical Neutrality between Realism and Instrumentalism". Abstract: I discuss the evolution of Carnap’s treatment of theoretical terms from the late1930s to his mature work on the Ramsey sentence formulation of scientific theoriesin the late 1950s and 1960s.I concentrate on Carnap’s use of this device toremain completely neutral between realism and instrumentalism.A central point ofdiscussion is his commitment to a purely logico-mathematical interpretation of thequantified existential variables in the Ramsey sentence.Far from being adesperate or ad hoc maneuver, I argue that this is essential to Carnap’s point ofview and, in particular, to the way in which he understands the characteristicallyabstract representations of modern mathematical physics throughout his intellectualcareer.In the end, Carnap recommends nothing more nor less than that we eschewfruitless “ontological” disputes in favor of cooperating with contemporarymathematical physicists in attempting (axiomatically) to clarify the mathematicaland conceptual foundations of their discipline.)