Dynamics of Hetu-Sadhya-Sambandha: Reconstructing Vyapti as a Clinical Diagnostic Predicate in Ayurveda

Abstract

The clinical diagnostic framework of Ayurveda integrates sensorial observation with structured logical inference, drawing primarily from the epistemological traditions of Nyāya and Vaiśeṣika Darśana. Fundamental to this framework is the relationship between the etiological sign (Hetu) and the inferred clinical condition (Sadhya), established through the principle of Vyapti (invariable concomitance). In contrast to modern biomedical diagnostics, which increasingly emphasize structural and molecular identification via technological means, Ayurvedic diagnostics-organized through the Nidāna Panchaka and Atura Parikṣa—focus on the functional assessment of Doṣa, Dhātu, and Mala using rigorous logical deduction (Anumana). This report reconstructs Vyapti as a clinical diagnostic predicate and evaluates its function in facilitating the transition from observable symptoms (Liṅga) to unobservable pathological states. A comprehensive review of the Charaka Saṃhitā Vimāna Sthana, alongside developments in First-Order Logic (FOL) and Bayesian Networks, reveals a pragmatic divergence: Ayurveda prioritizes observable "cause-effect sets" rather than the absolute universals of formal logic. The report also examines the functions of Tarka (confutation) and Hetvabhasa (logical fallacies) in reducing diagnostic errors, contending that formalizing these ancient predicates is essential for minimizing "unwarranted clinical variation" and supporting the integration of Ayurveda into digital health expert systems. This synthesis underscores Vyapti's capability to bridge traditional knowledge and probabilistic-based machine learning, advancing a "Systems Ayurveda" approach to individualized medicine.