Tetralemma
The tetralemma is a figure that features prominently in the logic of India. == Definition == It states that with reference to any logical proposition (or axiom) X, there are four possibilities: X {\displaystyle X} (affirmation) ¬ X {\displaystyle \neg X} (negation) X ∧ ¬ X {\displaystyle X\land \neg X} (both) ¬ ( X ∨ ¬ X ) {\displaystyle \neg (X\lor \neg X)} (neither) == Catuskoti == The history of the fourfold negation, the Catuskoti (Sanskrit), is evident in the logico-epistemological tradition of India and given the categorical nomenclature Indian Logic in Western discourse.