Logic / Nyaya Sastra, the Science of the regulative principles of thought was defined by Bhagavan Gautama, as that which illumines all Learning, Pradeepa Sarva Vidyanam, and is the instrument of all actions, Upadhi sarva karmanam, and is the refuge of all Moral Ethics, Ashraya Sarva Dharmanam, analysed compleley for the purpose of Knowledge, Vidyodeshe Pareekshitah !