The Bodhisattva's Study of Logic (Hetuvidyā)

The Buddhist logic (hetuvidyā) used by bodhisattvas is called the thesis, reason, and example (宗因喻). The thesis is the main proposition or viewpoint, the reason is the theory to be expounded, and the example is the illustrative case or factual instance. How are thesis, reason, and example to be applied? Let me explain with an example.

Someone says that the manas is one of the six faculties and, like the five physical faculties, is a material faculty. After we have engaged in logical reasoning that accords with the Dharma, we argue and expound that the manas is not a material faculty but a non-material faculty. The topic of the argument—that is, the viewpoint, the notion, and the proposition—is: the manas is a non-material faculty. Once the proposition is put forward, it must be expounded comprehensively and completely, presenting evidence and reasoning; after the principles have been clearly set forth, illustrative instances are then adduced, letting the facts speak. In this way, the theoretical evidence is tightly bound to the proposition, and the illustrative instances are tightly bound to the argument and the principles, each link interlocking with the next, seamlessly fitting together without gaps. This carries the strongest persuasive power; even if someone objects, they cannot articulate any grounds—opposing for the sake of opposing, debating for the sake of debating—and such opposition and debate become ineffectual.

Of course, if one lacks rigorous logical thinking and one's power of wisdom is insufficient, the evidence will be inadequate, there will be no strong theoretical support, and the content of the argument will not demonstrate the correctness of the proposition. If the reasoning is not rigorous and the exposition not comprehensive, there will be gaps and loopholes, and the lack of persuasive power will be insufficient to convince others. If the examples cited are far-fetched and cannot serve to substantiate the correctness and soundness of the evidence, the persuasive power of the evidence will also be greatly diminished, and one will fail to win people over. The capacity for logical reasoning reflects a practitioner's level of wisdom: the stronger the wisdom, the more meticulous the thinking, the more powerful the reasoning, the more persuasive it is, and the greater the capacity to deliver sentient beings. Those who practice the bodhisattva path, when encountering problems, should engage in deep and detailed contemplative practice (vipaśyanā-caryā), continually improving their capacity for logical thinking and observation. Of course, the prerequisite is very deep meditative concentration (samādhi); when contemplation is needed, one will cast aside all interference and devote oneself wholeheartedly to deep reflection.