Nagarjuna, the second-century Buddhist logician, argued that things have no fixed essence — that what we call 'understanding' is not a state you arrive at but a relationship between positions, always defined partly by what you've just left behind. This has a strange and practical application to learning: the moment you feel you've 'gotten' something, you've probably just stabilized a particular angle on it, not the thing itself. Modern cognitive scientists call this the 'illusion of explanatory depth' — Leonid Rozenblit and Frank Keil demonstrated it in 2002 by asking people to explain how a zipper works, only to find that confident belief in understanding collapsed immediately under the pressure of articulating mechanism. Nagarjuna would not have been surprised. His method — prasanga, the systematic exposure of what a position cannot account for — treats every apparent understanding as the opening move, not the closing one. The practical consequence for a Saturday: pick something you genuinely believe you understand well, and try to explain not what it does, but how, step by step, in writing. The gap that opens is not ignorance. It's where the next phase of learning begins.

If you stripped away the vocabulary you use to explain a subject you know well, what would remain — and how far would you get?

Drawing from Madhyamaka Buddhist Philosophy — Nagarjuna (Mūlamadhyamakakārikā, c. 2nd century CE) in dialogue with Leonid Rozenblit and Frank Keil (The Misunderstood Limits of Folk Science, 2002)