Interthematic Polarization

In recent epistemology, belief polarization is generally defined as a process by which a disagreement on a single proposition becomes more extreme over time. Outside of the philosophical literature, however, “polarization” is often used for a different epistemic phenomenon, namely the process by which people's beliefs on unrelated topics become increasingly correlated over time. This paper argues that the latter type of polarization, here labeled interthematic polarization, is often rational from each individual's point of view. This suggests that belief polarization is not necessarily a failure of individual rationality, but instead a failure of the social structures within which we live our epistemic lives.