Advaita Vedanta

The Proof of Brahman — Self-Luminosity

Brahman/Atman is self-luminous (svayamprakasha) — it is not known through any other means of knowledge but illuminates all other knowledge. It cannot be doubted because the doubter is itself.

Shankara's most powerful philosophical argument for Brahman's reality is based on its self-luminosity (svayamprakasha): Brahman/Atman cannot be doubted, negated, or unknown — because any doubt, negation, or attempt to know requires the presence of the doubter/negator/knower, which is Atman itself. Unlike objects (which are known through the senses, inference, or testimony), consciousness/Atman knows itself directly — it is the light by which all other things are illuminated. The analogy of the sun: the sun illuminates all other things but does not require another light source to be seen; similarly, consciousness illuminates all objects but does not require another consciousness to know it. This self-luminosity means Brahman cannot be argued out of existence: every argument against Brahman requires the use of consciousness, thereby presupposing what it denies. This is Advaita's version of Descartes' cogito — but taken further: not just 'I think, therefore I am,' but 'I am the awareness that makes thinking possible.'

Brahman/Atman is self-luminous — it shines by its own light and illuminates everything else.

Philosopher Frank Jackson's 'Mary's Room' thought experiment — documenting that phenomenal consciousness cannot be reduced to physical information — is the contemporary analogue to Shankara's argument from self-luminosity: consciousness has properties that cannot be captured in any third-person description, because it is inherently a first-person phenomenon.

Brahmasutra Bhashya

Written about in

• What Advaita Vedanta says about doubt

  Shankara's strongest move is that consciousness is self-luminous: doubting requires a doubter, so the one thing not available for doubt is the awareness doing it. He takes it further than the cogito — not "I think, therefore I am" but "I am the awareness that makes thinking possible."