Hrishikesh Joshi

This paper argues for the existence of a certain type of defeater for one’s belief that P—the presence of social incentives not to share evidence against P. Such pressure makes it relatively likely that there is unpossessed evidence that would provide defeaters for P because it makes it likely that the evidence we have is a lopsided subset. This offers, I suggest, a rational reconstruction of a core strand of argument in Mill’s On Liberty. A consequence of the argument is that on morally and politically laden issues in particular, a high degree of doxastic openness might be appropriate.

The American political landscape exhibits significant polarization. People’s political beliefs cluster around two main camps. However, many of the issues with respect to which these two camps disagree seem to be rationally orthogonal. This feature raises an epistemic challenge for the political partisan. If she is justified in consistently adopting the party line, it must be true that her side is reliable on the issues that are the subject of disagreements. It would then follow that the other side is anti-reliable with respect to a host of orthogonal political issues. Yet, it is difficult to find a psychologically plausible explanation for why one side would get things reliably wrong with respect to a wide range of orthogonal issues. While this project’s empirical discussion focuses on the US context, the argument generalizes to any situation where political polarization exists on a sufficiently large number of orthogonal claims.