Charak Samhita
त्रिविधं खलु रोगविशेषविज्ञानं भवति; तद्यथा आप्तोपदेशः, प्रत्यक्षम्, अनुमानं चेति ॥३॥
॥ Three methods for knowledge of disease॥ Specific features of diseases can be determined in three ways – by means of aptopadesha (authoritative instruction), pratyaksha (direct observation), and anumana (inference).
english translation
trividhaM khalu rogavizeSavijJAnaM bhavati; tadyathA AptopadezaH, pratyakSam, anumAnaM ceti ॥3॥
hk transliteration by Sanscript