Kaṭha Upaniṣad · 2.3.13

अस्तीत्येवोपलब्धव्यस्तत्त्वभावेन चोभयोः । अस्तीत्येवोपलब्धस्य तत्त्वभावः प्रसीदति ॥ १३ ॥

astītyevopalabdhavyastattvabhāvena cobhayoḥ | astītyevopalabdhasya tattvabhāvaḥ prasīdati || 13 ||

It should be known as ‘Is,’ and also its true nature. Of these two, for one who knows It as existent, its true nature becomes manifest.

Knowledge progresses in two stages. First, the conviction that the Ātman asti (is, exists), based on logical investigation and faith in scripture. Then, the tattvabhāva (true nature, real being) is revealed directly.

These two—the asti (conceived existence) and the tattvabhāva (real nature)—are like the map and the territory. The map is useful, but it is not the territory. One who confuses the concept of Ātman with Ātman itself remains at the theoretical level.

The prasīdati (becomes manifest, becomes clear, becomes serene) describes the natural revelation that occurs when the mind prepared by initial conviction becomes completely still. One need not fabricate the truth; it reveals itself when obstacles are removed. Yoga is this process of removal, not of acquisition.