 Schmithausen notes that the mention of the four noble truths as constituting "liberating insight", which is attained after mastering the Rupa Jhanas, is a later addition to texts such as Majjhima Nikaya 36.Both Schmithausen and Bronkhorst note that the attainment of insight, which is a cognitive activity, cannot be possible in state wherein all cognitive activity has ceased.According to Vetter and Bronkhorst, "dhyana" itself constituted the original "liberating practice".