The topic of unknowns also is a crucial aspect of debates about rationality. According to some, a hallmark of rationality is knowing what you don't know, and taking into account how different kinds of unknowns require different treatments. As I mentioned in one of the other webpages, most of the debates have centred on uncertainty and the question of whether probability can be "all there is" to uncertainty for a rational agent. One of my blog posts introduces some of the ideas behind this question, and the philosopher Alan Hájek and I have a paper in which we present some novel arguments that rationality requires recogizing that many probabilities are imprecise (Hájek & Smithson, 2012).

There is another connection between ignorance and rationality, namely "rational ignorance". Illya Somin is one of the pioneers of the concept that it is rational not to know something if the cost of gaining that knowledge exceeds the benefits. You can see the gist of his ideas here. The authors of this recent paper make a case that "critical ignoring should be part of school curricula on digital information literacy", but they seem unaware that Somin was there long before them.