The Gypsy Lawer 30 Years Later

Abstract

Suppose John has good evidence for believing P. However, he ignores the evidence and believes P for some bad reasons. He is not justified in holding the belief, because his believing P is not based on the evidence. One plausible account of the basing relation is a causal account. According to the causal account, the belief P is based on evidence E at t if and only if either E causes the belief P at t or E counterfactually causes the belief P at t in the sense that E would cause the belief P if it had not been caused by its actual cause. Apparently, the counterfactual clause is introduced to accommodate beliefs that are ill-formed initially but justified by later identified or later collected evidence.