The starting point in philosophical discussion is epistemology-establishing the basis of knowledge. Srila Jiva Goswami lists in his Sad-sandharbha ten methods of attaining knowledge, including tradition, history, guessing, comparison, probability, and logic, and shows how all of them fit into three main categories:
Pratyaksa (Direct sense perception / direct experience) - The knowledge we get through the five senses,
Anumana (Mental reasoning / inference) - Literally "to follow (anu) the mind (mana)" ,
Sabda (Authoritative testimony / hearing from bona fide authority without interpretation) - Literally "sound"