Editing History of logic (section)

=== Buddhist logic ===

==== Nagarjuna ====
[[Nagarjuna]] (c. 150–250 AD), the founder of the [[Madhyamaka]] ("Middle Way") developed an analysis known as the [[catuṣkoṭi]] (Sanskrit), a "four-cornered" system of argumentation that involves the systematic examination and rejection of each of the four possibilities of a proposition, ''P'':
# ''P''; that is, being.
# not&nbsp;''P''; that is, not being.
# [[File:Eight Patriarchs of the Shingon Sect of Buddhism Nagarjuna Cropped.jpg|thumb|Painting of Nāgārjuna from the ''Shingon Hassozō'', a series of scrolls authored by the [[Shingon]] school of Buddhism. Japan, [[Kamakura period]] (13th–14th century)]]''P'' and not&nbsp;''P''; that is, being and not being.
# not (''P'' or not&nbsp;''P''); that is, neither being nor not being.{{Paragraph break}}Under [[propositional logic]], [[De Morgan's laws]] would imply that the fourth case is equivalent to the third case, and would be therefore superfluous, with only 3 actual cases to consider.