Validity as a thick concept.

This paper presents a novel position in the philosophy of logic: I argue that validity is a thick concept. Hence, I propose to consider validity in analogy to other thick concepts, such as honesty, selfishness or justice. This proposal is motivated by the debate on the normativity of logic: while logic textbooks seem simply descriptive in their presentation of logical truths, many have argued that logic has consequences for how we ought to reason, for what we ought to believe, or for what we ought to infer. How can logic be normative, if it appears to be descriptive? According to the proposal of this paper, the normativity of logic can be explained because a thick concept is in play: validity. Thus, I argue that the debate on how to best characterize validity and the debate on logic's normativity are more connected than we think, because validity is a thick concept. [ABSTRACT FROM AUTHOR]