This has led some to wonder whether the Buddha does not employ a deviant logic. Such suspicions are strengthened by those cases where the options are not two but four, cases of the so-called tetralemma (
catuṣkoṭi ). For instance, when the Buddha is questioned about the post-mortem status of the enlightened person or
arhat (e.g., at M I.483–8) the possibilities are listed as: (1) the
arhat continues to exist after death, (2) does not exist after death, (3) both exists and does not exist after death, and (4) neither exists nor does not exist after death. When the Buddha rejects both (1) and (2) we get a repetition of ‘neither the same nor different’. But when he goes on to entertain, and then reject, (3) and (4) the logical difficulties are compounded. Since each of (3) and (4) appears to be formally contradictory, to entertain either is to entertain the possibility that a contradiction might be true. And their denial seems tantamount to affirmation of excluded middle, which is
prima facie incompatible with the denial of both (1) and (2).
Buddha (Stanford Encyclopedia of Philosophy)