A 2nd-century logician argued a claim can be true, false, both, or neither

Most logic assumes a statement is either true or false. Nagarjuna's catuskoti ('four corners') instead tests every claim against four possibilities — true, false, both, or neither — and in his central text uses it to argue that even the question of whether the Buddha exists after death resists a straight answer.

— Nagarjuna, Mulamadhyamakakarika (Fundamental Verses on the Middle Way) — c. 2nd century CE