Definitions of Logic

Most treatises on logic begin with a discursion on the difficulty of defining the subject. Nevertheless, a definition is felt to be necessary. Here is a short summary of Definitions of logic that logicians throughout history have attempted, arranged in approximate chronological order.


 * The tool for distinguishing between the true and the false (Averroes).
 * The science of reasoning, teaching the way of investigating unknown truth in connection with a thesis (Robert Kilwardby).
 * The art whose function is to direct the reason lest it err in the manner of inferring or knowing (John Poinsot).
 * The art of conducting reason well in knowing things (Antoine Arnauld).
 * The right use of reason in the inquiry after truth (Isaac Watts).
 * The Science, as well as the Art, of reasoning (Richard Whately).
 * The science of the operations of the understanding which are subservient to the estimation of evidence (John Stuart Mill).
 * The science of the laws of discursive thought (James McCosh).
 * The science of the most general laws of truth (Gottlob Frege).
 * The science which directs the operations of the mind in the attainment of truth (George Hayward Joyce).
 * The branch of philosophy concerned with analysing the patterns of reasoning by which a conclusion is drawn from a set of premisses (Collins English Dictionary)
 * The formal systematic study of the principles of valid inference and correct reasoning (Penguin Encyclopedia).