Tattvamasi, the profound declaration of the Chāndogya Upaniṣad (C.U. VI.8.7), has two dimensions, social (loka) and transcendental (lokottara). The philosophical discussions on this concept often overlook the ‘intersubjective’ aspect, instead focusing solely on the transcendental. To address this issue, this study investigates the intersubjectivity (Humanistic Nondualism) implied in Tattvamasi, drawing on the inclusive spirit of the Upaniṣadic texts and the works of Śrī Śaṅkara and Śrī Nārāyaṇa Guru.