Logic

Logic (from the Greek λογική logikē)^[1] is the analysis and appraisal of arguments.^[2] Logic is used in most intellectual activities, but is studied primarily in the disciplines of philosophy, mathematics, and computer science.

Logic was established as a discipline by Aristotle, who gave it a fundamental place in philosophy. The study of logic was part of the classical trivium.
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Many treatises on logic begin with a discursion on the difficulty of defining the subject, many do not even attempt to provide a definition. Nevertheless, many definitions have been offered because it is felt to be necessary.
This article divides the definitions into two classes: first are the simple definitions, that consist of a pithy sentence characterising the topic; second are theoretical definitions, where the definition of logic turns on an analysis the definer provides.

Simple definitions of logic

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).

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