The genus problem of populism presents one of the most vexing conceptual questions across the social sciences: Some theorists believe that populism is nothing more than an assembly of discursive patterns, while others maintain that populism is a strategy to gain political power. Then there are those that argue that populism is a thin ideology that lacks a coherent set of guiding principles. The paper intervenes in this debate in two ways: First, it offers a methodological apparatus for evaluating and (...) developing contested concepts such as populism. Second, it puts forward and defends the claim that populism can be fruitfully understood as a coherent ideology that rests on four foundational principles. These principles, I will argue, are necessary for explaining the paradigmatic beliefs and dispositions exhibited by exponents of populism. One of the key characteristics of populism, on the account developed in this paper, is its peculiar epistemic stance. (shrink)