Fallibility in formal macroeconomics and finance theory

This note focuses on George Soros's challenge to macroeconomics and finance theory that any valid methodology of social science must explicitly recognize fallibility in a Knightian sense. We use a simple algebraic example to sketch how extant models formalize fallibility. We argue that contemporary theory's epistemological and empirical difficulties can be traced to assuming away fallibility in a Knightian sense. We also discuss how imperfect knowledge economics provides a way to open mathematical models to such fallibility, while preserving economics as an empirical science.