Conditionals and non-constructive reasoning

This chapter examines how the premise of an introduction inference has itself been derived. It first considers inferring a conditional, ‘if not-p then q’, as a conclusion from a disjunction, ‘p or q’. The chapter then asks: Under what conditions is this inference justified? Will people endorse this inference when it is justified and refuse to endorse it otherwise? It is argued that the justification of this inference depends on how the premise ‘p or q’ has been justified.