The Mūrtāmūrtabrāhmaṇa (II.3) of the Bṛhadāraṇyakopaniṣad introduces the néti néti formula and explains it. From Sanskrit commentaries we can gather that this formula was traditionally interpreted in two ways. The second of them, the one adopted by Śaṅkara, has become the favourite of most of the modern translations; the first interpretation has not attracted the attention of a modern scholar.
On the other hand, a very competent scholar like Geldner (1928) has made an exception and interpreted the formula in an extra-ingenious way, as double negation, which was never considered in the tradition. This interpretation has now been revived in Slaje 2009. This asks us to re-examine the issue, and I will do so in my lecture by rereading the related portions of the Bṛhadāraṇyakopaniṣad.