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.
http://en.wikipedia.org/wiki/Logic
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).
