Navya-Nyāya — the rigorous 13th-century Indian school of formal logic founded by Gaṅgeśa Upādhyāya — developed a concept called vyāpti, the strict invariable concomitance between two things that must hold before you can call one a reliable sign of the other. Smoke is only evidence of fire if smoke and fire co-occur without exception across every known case, not merely most cases. Modern logicians and data scientists would recognize this as a demand for a universal rather than a probabilistic conditional — and Gaṅgeśa held that our habitual inferences constantly slip this standard. We infer 'expert' from 'confident tone.' We infer 'clarity' from 'brevity.' We infer 'understanding' from 'smooth summary.' None of these are genuine vyāpti — they are correlations we have promoted, without scrutiny, to the status of laws. The practical consequence is precise: before you rely on a sign to ground a conclusion, the Navya-Naiyāyikas would ask you to enumerate the counter-instances explicitly, not just intuit that they are rare. This is harder than it sounds. The very signs we trust most are the ones we stopped testing first.

What is a conclusion you routinely draw from a single recurring signal — and what would it take to produce one genuine counter-instance to it?

Drawing from Navya-Nyāya (New Logic school of Indian philosophy) — Gaṅgeśa Upādhyāya (13th century CE, Tattvacintāmaṇi)