Logic (from the Greek λογική, logikē) refers to both the study of modes of reasoning (which are valid, and which are fallacious) and the use of valid reasoning. In the latter sense, logic is used in most intellectual activities, including philosophy and science, but in the first sense, is primarily studied in the disciplines of philosophy, mathematics, semantics, and computer science. It examines general forms that arguments may take. In mathematics, it is the study of valid inferences within some formal language. Logic is also studied in argumentation theory.

Logic was studied in several ancient civilizations, including India, China, and Greece. In the west, logic was established as a formal discipline by Aristotle, who gave it a fundamental place in philosophy. The study of logic was part of the classical trivium, which also included grammar and rhetoric.

Logic is often divided into three parts, inductive reasoning, abductive reasoning, and deductive reasoning.

Read more about Logicus:  The Study of Logic, History

Other articles related to "logicus":

Logicus - Topics in Logic - Rejection of Logical Truth
... Friedrich Nietzsche provides a strong example of the rejection of the usual basis of logic his radical rejection of idealisation led him to reject truth as a "...mobile army of metaphors, metonyms, and anthropomorphisms—in short.. ... metaphors which are worn out and without sensuous power coins which have lost their pictures and now matter only as metal, no longer as coins." His rejection of truth did not lead him to reject the idea of either inference or logic completely, but rather suggested that "logic into existence in man's head of illogic, whose realm originally must have been immense ...
Technogamia - The Allegory
... Geographicus and his servant Phantastes Logicus and his servant Phegmaticus Grammaticus the schoolmaster and Choler his usher Medicus and his servant Sanguis Poeta ... with Poeta Grammaticus pursues Rhetorica, though she prefers Logicus ... The cold-hearted Logicus remains a bachelor and becomes Polites' assistant, and order is restored to the sciences once again ...