Sri Aurobindo translates Katha Upanishad, First Cycle: Second Chapter, Verse 14: “Nachiketas speaks: ‘Tell me of That which thou seest otherwhere than in virtue and otherwhere than in unrighteousness, otherwhere than in the created and the uncreated, otherwhere than in that which has been and that which shall be.’ ”
The mental consciousness functions in a world consisting of dualities. We cannot conceive of pleasure without pain, joy without sorrow, virtue without vice. We constantly uphold the idea that one cannot have one without the other. This is due to the function and form of the mental consciousness which is limited to dualistic thinking. This also leads us to create extremes in the way we try to solve problems and leads eventually to gridlocked ideas that battle with one another but do not have the power to ultimately prevail. There is a constant turmoil as one idea rises and the opposite idea sinks, and then the process reverses over time. We are locked into these dualities as long as we are bound within the framework of the mental worldview.
When Nachiketas therefore requests knowledge of that which is other than or beyond the various forms of duality, he is asking for a new frame, a new status of consciousness that can be both beyond all these dualities, and yet still encompass and harmonize them.
The Bhagavad Gita describes the status of the Kshara Purusha, the “manifest”, the Akshara Purusha, the “unmanifest” and the Purushottama, the supreme Purusha which is beyond both the manifest and the unmanifest. This provides us a foundation to understand the request of Nachiketas here in the Katha Upanishad. Nachiketas is asking for direction on how to move beyond the dualities of the mind to gain a standpoint of Oneness, the divine standpoint.
Sri Aurobindo, The Upanishads, Katha Upanishad, pp. 213-241, and Kapali Sastry, Lights on the Upanishads, pp. 104-129