1. The Vedic and Vedantic imagery is foreign to our present mentality which does not believe in the living truth of the symbol. Our imagination has been intimated by the intellect. Hence we are unable to see the psychic and spiritual vision of the Upanishads.
2. Upanishads are very far from a childish, primitive or barbarous mysticism. The poetic intuitive language of the Upanishads is the natural expression of a highly evolved spiritual culture.
3. The intuitive thought of the Upanishads starts from this concrete imagery and symbols, these words are wholly expressive to the mind of the seer but veils their deepest sense to the ordinary intelligence. They then move beyond to a magnificently open and sublime imagery that at once reveals the spiritual truth.
4. The prose Upanishads show us this process of the early mind of India at its work using the symbol and then passing beyond it to the overt expression of the spiritual significance.
5. The above mentioned theme is well illustrated in a passage from the Prashna Upanishad explaining the power and significance of the syllable AUM.