hindu-selfWe're still mapping where this idea was first discussed. Key passages and related ideas below.
The Intuitive Sheath (Vijñānamaya-Kośa)
The layer of insight and 'I' — the discerning intellect, subtler than passing thought yet still not the self.
The vijñānamaya-kośa is the 'sheath made of understanding' — the higher mind or intellect, the faculty that discerns, judges, and says 'I.' Subtler than the chattering thought-stream, it is the layer of insight and decision, closer to the core than the busy surface mind. Yet it too is a layer, not the self: the awareness that lights up even our deepest understanding stands behind it.
Key passages(2)
Vivekacūḍāmaṇi 184↗explains
Vivekacūḍāmaṇi · Śaṅkara (traditionally ascribed; authorship doubted)
Very high
Bṛhadāraṇyaka Upaniṣad · Vedic Revelation (śruti)
High