Possible Worlds and Imagination in Informal Logic
John Nolt · Informal Logic · 1984
Logic's main task is to evaluate strength of reasoning.By "strength of reasoning," I mean the degree of logical connection between premises and conclusion, regardless of the premises' truth.Of course we can't tell whether an argument ought to persuade us unless we know whether its premises are true.But truth of premises is in general not a logical matter.Logic is concerned, rather, with the question, "If the premises were true, how likely would the conclusions' truth be?This likelihood is strength of reasoning.