NonDualism

Does Bhagavad-gita teach Advaitavada? | Wisdom Munches 6 | Chaitanya Charan

What are the meaning of Nirishvarvadi, Brahmavadi, Mayavadi, Shunyavadi, Nirakarvadi, Nirvisheshvadi terms?

If guru-shishya parampara was always present how could monism become so prominent?