What Makes Confirmation Bias Irrational?

Confirmation bias is the human tendency to interpret new information in such a way that it confirms their prior beliefs. In Post-Truth, for example, the philosopher Lee McIntyre, for example, defines it as “the tendency to give more weight to information that confirms one of our preexisting beliefs.” But what, precisely, is irrational about such a tendency? If I were to see something now that looks like a polar bear, my preexisting belief that there are no polar bears near here will rightly lead me to give less weight than I otherwise would to this visual information. Analogously, there can be no real quarrel with a willingness to infer that studies supporting one’s theory-based expectations are more probative than, or methodologically superior to, studies that contradict one’s expectations. And being a total ‘blank slate’ with no assumptions or preconceptions is not a desirable or realistic starting point. So if biases are dispositions to make false or irrational judgements, so-called

Confirmation bias is the human tendency to interpret new information in such a way that it confirms their prior beliefs. In Post-Truth, for example, the philosopher Lee McIntyre, for example, defines it as “the tendency to give more weight to information that confirms one of our preexisting beliefs.” But what, precisely, is irrational about such a tendency? If I were to see something now that looks like a polar bear, my preexisting belief that there are no polar bears near here will rightly lead me to give less weight than I otherwise would to this visual information. Analogously, there can be