The Four Principles of Reasoning

T1606 grounds each of these four principles in a concrete example, and together they cover every basic form correct reasoning about the Dharma can take. The principle of dependence is illustrated by ordinary causal necessity itself: a sprout arises only in dependence on a seed together with season, water, and soil; a moment of consciousness arises only in dependence on a sense faculty, an object, and mental attention — nothing conditioned simply appears from nowhere. The principle of function is illustrated by the specific, non-interchangeable roles distinct things actually play: the eye faculty serves specifically as the basis for eye-consciousness, form serves specifically as its object, and eye-consciousness itself serves specifically to discern form — just as a goldsmith and a silversmith each skillfully work their own distinct material into finished ornaments, each dharma performs a function proper to itself alone, not to any other. The principle of proof is illustrated by the actual practice of establishing a claim through the valid means of knowledge — direct perception, inference, and reliable testimony — proposing a thesis and defending it only by statements that these do not contradict. And the principle of inherent nature is illustrated by facts so basic they require no further proof at all: fire simply burns, water simply flows and moistens — as a sūtra says, the eye, though perfectly formed and pure, is empty, is not permanent, and so on up through being without self, simply because that is its nature, as it has always already been. Together these four principles distinguish what actually needs an argument (dependence, function, proof) from what is instead the very bedrock on which every such argument ultimately rests (inherent nature).