Formal approaches are very influential in philosophy with many successes in logic, formalepistemology, semantics, and normative decision theory. Past philosophical formal developmentshave been influential outside of philosophy in areas as diverse as computing, linguistics, andeconomics. Formal approaches are understood and promoted as instances of scientific philosophy.Like all methods, formal approaches have systematic benefits and costs, global strengths andweaknesses. Practitioners of formal philosophy have articulated cogent accounts of the ongoingpromise of their methods. By contrast, potential limitations, abuses of formal methods, and indirectharms have been relatively neglected.In this project we explore the arguments against formal approaches in philosophy in historical andsystematic context. On the historical side, this project aims to recover now largely forgotten debatesover the merits of formal techniques in philosophy in the 18th century, roughly, the period betweenKant and Newton. While 'philosophy' had a broader signification then, several of the arguments arestill significant for today's debates over the methods of philosophy (so-called meta-philosophy). Onthe systematic side: the great attraction of formal approaches is their topic neutrality. Yet, topicneutrality entails that many substantive issues are extrinsic to formal methods. The implication ofthis may be that formal methods need to be supplemented in non-trivial fashion.