Logic

Logic is the study of the principles of valid inference and demonstration. The word derives from Greek λογική (logike), fem. of λογικός (logikos), "possessed of reason, intellectual, dialectical, argumentative", from λόγος logos, "word, thought, idea, argument, account, reason, or principle". As a formal science, logic investigates and classifies the structure of statements and arguments, both through the study of formal system of inference and through the study of arguments in natural language. The field of logic ranges from core topics such as the study of validity, fallacies and paradox, to specialized analysis of reasoning using probability and to arguments involving causality. Logic is also commonly used today in argumentation theory. Traditionally, logic was considered a branch of philosophy, a part of the classical trivium of grammar, logic, and rhetoric. Since the mid-nineteenth century ''formal logic'' has been studied in the context of foundations of mathematics, where it... full article at wikipedia