Neoliberalism is often framed as the victorious doctrine against Soviet communism: its nemesis and antidote. When we examine how Soviet and neoliberal economics understand the nature of political economic reality, however, British neoliberalism and Soviet communism turn out to be exact mirror images. In this introduction, Innes sets out the book’s argument, and the philosophy of science perspective on which it is based. Why do Soviet and neoliberal orthodoxies have such affinities? Both are based on closed-system reasoning about the political economy; both assert that there are predetermined laws of the economy that each doctrine alone can apprehend, and both schemes require the operation of a universal and consistent rationality: socialist versus utilitarian. The ‘critical realist’ perspective in the philosophy of science focuses on how we apprehend reality, and what we can reasonably claim to know about it, and the introduction explains how this lens allows us to see why a ‘governing science’ built on closed system reasoning is doomed to produce a rising tide of unanticipated social and institutional consequences in societies that are evolving, open, and hence uncertain systems.