According to the history of logic in the Encyclopaedia Britannica, logic emerged from the study of philosophical arguments, and the realisation that were general patterns by which one could distinguish valid and invalid forms of argumentation. The systematic study of logic was begun by Aristotle, who established a system of formal rules and strategy for reasoning. The use of the word strategy is intentional:
The practice of such techniques in Aristotle’s day was actually competitive, and Aristotle was especially interested in strategies that could be used to “win” such “games.” Naturally, the ability to predict the “answer” that a certain line of questioning would yield represented an important advantage in such competitions. Aristotle noticed that in some cases the answer is completely predictable—viz., when it is (in modern terminology) a logical consequence of earlier answers. Thus, he was led from the study of interrogative techniques to