What it claims
The world appears to contain two things: a self that is aware, and a world it is aware of. Non-duality says: look closer. The self that seems to stand apart from experience is itself an experience — a thought, a feeling, a memory — appearing in the same field as everything else. There is no observer behind the observing. There is just observing. The Sanskrit advaita names this directly: not two.
This is not a metaphysical position to be argued. It's a recognition to be looked into. The teachings most associated with non-duality — Ramana Maharshi's self-enquiry, the dialogues collected in I Am That — work less by adding new beliefs than by dissolving the assumption of a separate observer. The result, when it lands, is described as a peace that doesn't depend on circumstances, because there is no separate self left to be threatened by them.
Where to encounter it
Rupert Spira is the most patient living English-language teacher of the view — his answers to long-form questions are the closest thing to a manual the tradition has. Listen to How the Infinite Knows the Finite or How Do I Move From Intellectual Understanding to Lived Knowing for representative pieces. Adyashanti's Do Nothing is a lighter doorway. Mooji and Francis Lucille come from the same lineage with different temperaments. For the foundational text, Spira's *Being Aware of Being Aware* is the shortest serious introduction in English.
What it isn't
Non-duality is sometimes confused with the claim that nothing exists, or that distinctions don't matter. Neither is its claim. The cup on the table is still a cup. The pain in the body is still pain. The teaching is about the background in which all of these appear — and the recognition that the apparent separateness of the one to whom they appear is itself one of the appearances.
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