Nidana — The Science of Causation
Nidana (etiology) is Ayurveda's sophisticated understanding of disease causation — the systematic analysis of how imbalanced doshas, poor lifestyle choices, and environmental factors combine to produce specific disease manifestations.
Nidana (literally 'causation' or 'rope that binds') is the Ayurvedic science of disease etiology. Charaka identifies three fundamental causes of all disease: Asatmyendriyartha Samyoga (improper contact of sense organs with their objects — too much, too little, or wrong type of sensory stimulation), Prajnaparadha (crimes against wisdom — acting against one's better knowledge), and Parinama (time and seasons — the natural cycles of Vata, Pitta, and Kapha throughout the day, seasons, and stages of life). From these three root causes, the complex chain of dosha aggravation, Srotas obstruction, Dhatu damage, and symptom manifestation unfolds in a predictable sequence that Ayurvedic diagnostics traces backwards from symptom to root cause. This causal framework — particularly the concept of Prajnaparadha (knowingly acting against one's health) — anticipates the lifestyle medicine understanding that most chronic disease is behaviorally driven.
Three are the causes of all disease: improper sensory contact, crimes against wisdom, and the imbalanced effects of time.
Lifestyle medicine research has confirmed that approximately 80% of chronic disease burden is attributable to behavioral factors (diet, physical activity, smoking, alcohol, sleep) — what Ayurveda called Prajnaparadha (crimes against wisdom) — validating the ancient emphasis on behavioral causation in disease.
Charaka Samhita