Abstract

Like all reasoning, practical reasoning is a process that takes a person from some of her existing mental states to a new mental state. Theoretical reasoning concludes in a belief; practical reasoning in an intention. This paper concentrates on instrumental reasoning, a species of practical reasoning in general. It argues that instrumental reasoning is correct if the content of the reasoning is a valid derivation, just as theoretical reasoning is correct if its content is a valid derivation. It also argues that neither theoretical nor practical reasoning gives a reason for its conclusion. If a piece of reasoning is correct, it concludes in a state - a belief or an intention - that is rationally required by the states it is derived from, but rationally requiring a conclusion is not the same as giving a reason for it.