Aitareya Upanishad The series of 'jnA' - the 'to know' jnA is knowing pra-jnA means before knowing or the 'first' of knowing, the 'prominent' knowing etc. prajnA is awareness. It is the stage before 'knowing'. It is the 'first' of the series of knowings. A stage of just awareness. prajnA is just the basic awareness with an entity of it being an entity. Because it is the foremost, first of the knowing, it is called pra-jnA. jnAna is the physically/practically knowing. vi-jnAna is logically knowing. Here the prefix 'vi' adds stress to the knowing and takes to the next level of 'knowing' which is logically knowing. ajnAnana is not knowing. Sloka 5.1 ko 'yam atmeti vayam upasmahe sa atma yena va pasyati yena va srnoti yena va gandhan ajighrati yena va vacam vyakaroti yena va svadu casvadu ca vijanati. Meaning Who this atma worshiped by us..? Is that one that sees, that hears, that smells