ABSTRACT
In this book, David Over and I discussed much philosophical and psychological writing on conditionals, using the former as an inspiration for a new psychological account. The psychological evidence we reviewed did not simply concern the new tasks on the judgement of the probability of conditionals and studies of the defective truth table. We also reviewed the large literature on the conditional elimination inferences, MP, MT, AC and DA, which have been studied extensively with both abstract and various forms of thematic materials. Discrepant findings between abstract and thematic tasks inspired us to produce an alternative view of what are termed biconditional statements: classically described as “if and only if p then q”. In bivalent logic, there is only one kind of biconditional in which TT and FF are true and TF and FT are false. Such a statement sanctions all four inferences, but this pattern is rarely observed in experiments.
