From Natural Thinking to Scientific Reasoning: Concepts of logica naturalis and logica artificialis in Late-Medieval and Early-Modern Thought

This article investigates the late-medieval and early-modern use of the concepts of natural and artifical logic. Natural logic is the inborn capacity to argue, common to all human beings, whereas artifical logic is the expression and description of this ability through formal rules that were codified in logical handbooks. According to most authors until the time of Kant, artificial logic must take its starting point from natural thinking and natural speech, since the organizational patterns of the human mind reveal themselves only in speaking about and discussing extra-mental reality. For these medieval and early-modern logicians, therefore, natural arguing is the object of artifical logic, which they developed in their logical treatises and taught in schools and universities.