logic

Branch of philosophy that studies valid reasoning and argument. It is also the way in which one thing may be said to follow from, or be a consequence of, another (deductive logic). Logic is generally divided into the traditional formal logic of Aristotle and the symbolic logic derived from Friedrich Frege and Bertrand Russell.

Aristotle's Organon is the founding work on logic, and Aristotelian methods, as revived in the medieval Christian church by the French scholar Peter Abelard in the 12th century, were used in the synthesis of ideas aimed at in scholasticism. As befitted the spirit of the Renaissance, the English philosopher Francis Bacon considered many of the general principles used as premises by the scholastics to be groundless; he envisaged that in natural philosophy principles worthy of investigation would emerge by ‘inductive’ logic, which works backwards from the accumulated facts to the principle that accounts for them.

The concept of fuzzy logic was proposed 1965 to enable computer controlled devices to deal with vague concepts.