Abstract

It is usually held that what distinguishes a good inference from a bad one is that a good inference is truth-preserving. Against this view, this paper argues that a logical inference is good or bad depending not on whether it is truth-preserving or not, but whether it belongs to a logical system the addition of which makes a deductively conservative extension of the derivation relations among the atomic statements. To so argue, the paper first contends that the meaning of the logical operators of classical logic is determined not by their connections to truth, but by their inferential roles. It is claimed in conclusion that there is no genuine issue over which logic, classical or intuitionistic, is the correct logic, for they are both conservative in the relevant sense.