The fact that the Great Learning explicates ge wu in terms of “extending knowledge” might seem to support Zhu Xi’s interpretation.  However, Wang offers a plausible alternative explanation: “To fully extend one’s knowledge is not like the so–called ‘filling out’ of what one knows that later scholars [like Zhu Xi] talk about. It is simply to extend fully the ‘pure knowing’ of my own mind.  Pure knowing is what [Mencius] was talking about when he said that all humans have ‘the mind of approval and disapproval.’ The mind of approval and disapproval ‘knows without pondering’ and is ‘capable without learning’ ” (Tiwald and Van Norden 2014, 248, glosses  mine).[9]  Wang is suggesting that “extending knowledge” refers simply to exercising our innate faculty of moral awareness, which Mencius refers to as “pure knowing.” As David S. Nivison explains, “We might say that Wang’s ‘extending’ of knowledge is more like extending one’s arm than, say, extending one’s vocabulary” (Nivison 1996a, 225).