 The Sāṃkhya and Yoga schools draw inspiration for their metaphysics of persons from the Upaniṣads and develop the insight that the real essence of a person is the soul or in Sāṃkhya terminology, the Spirit (puruṣa). But unlike the Vedānta, the Sāṃkhya and Yoga philosophers do not regard the multiplicity of true persons as a mere illusion. They speak of the absolute puruṣa (īśvara) and individual puruṣas (jīvas). Verse 18 of the Sāṃkhya-kārikā offers a proof and explanation for the existence of multiplicity of real persons