This method of scripture interpretation distinguishes Ramanuja from Ādi Shankara. Shankara's exegetical approach "Samanvayat Tatparya Linga" with "Anvaya-Vyatireka", states that for proper understanding all texts must be examined in their entirety and then their intent established by six characteristics, which includes studying what is stated by the author to be his goal, what he repeats in his explanation, then what he states as conclusion and whether it can be epistemically verified. Not everything in any text, states Shankara, has equal weight and some ideas are the essence of any expert's textual testimony. This philosophical difference in scriptural studies, helped Shankara conclude that the Principal Upanishads primarily teach monism with teachings such as "Tat tvam asi", while helping Ramanuja conclude that qualified monism is at the foundation of Hindu spirituality.