Handbook Of The History Of Logic 3 - The Rise Of Modern Logic From Leibniz To Frege
The meaning of the word 'logic' has changed quite a lot during the development of logic from ancient to present times. Therefore any attempt to describe "the logic" of a historical author (or school) faces the problem of deciding whether one wants to concentrate on what the author himself understood by 'logic' or what is considered as a genuinely logical issue from our contemporary point of view. E.g., if someone is going to write about Aristotle's logic, does he have to take the entire Organon into account, or only the First (and possibly the Second) Analytics? This problem also afflicts the logic of Gottfried Wilhelm Leibniz (1646-1716). In the late 17th century, logic both as an academic discipline and as a formal science basically coincided with Aristotelian syllogistics. Leibniz's logical work, too, was to a large extent related to the theory of the syllogism, but at the same time it aimed at the construction of a much more powerful "universal calculus". This calculus would primarily serve as a general tool for determining which formal inferences (not only of syllogistic form) are logically valid.