INFORMAL LOGIC AND LOGIC

This article examines the relation between informal logic and logic. Informal logic originated with the rejection of formal logic in the analysis and evaluation of natural language discursive arguments. Various alternatives are mentioned: fallacy theory; acceptability, relevance and sufficiency; and argument scheme theory. The last is described at some length as involving warrants, schemes, and critical questions. Argument scheme analysis and critique, while informal, has been used in AI to develop computer programs to analyze, assess and even construct arguments in natural language. Thus informal and formal logic have come together.