Śvetāśvatara Upaniṣad · 1..9
इमे वै सप्तर्षयो व्यासश्च कश्यपश्चात्रिः प्राजापतिः सोऽयमस्मिञ्छारीरे पुरुषः सोऽस्मिन्नन्तर्हृदय आकाशः तस्मिन्यदन्तरं तदन्वेष्टव्यं तद्वैव विजिज्ञासितव्यम्
ime vai saptarṣayo vyāsaśca kaśyapaścātriḥ prājāpatiḥ so'yam asmiñchārīre puruṣaḥ so'sminnantarhṛdaya ākāśaḥ tasminyadantaraṃ tadanveṣṭavyaṃ tadvaiva vijijñāsitavyam
These seven ṛṣis, Vyāsa, Kaśyapa, Atri and Prajāpati —this Puruṣa in this body, He is within the space of the heart. That which is within that space must be sought, that must be investigated.
The direction of search turns inward. The great ṛṣis mentioned —Vyāsa, Kaśyapa, Atri— are not merely historical figures but representations of aspects of our own consciousness. The Puruṣa dwells in the “space of the heart” (hṛdaya ākāśa), the inner sanctuary where Truth is revealed. In our yoga practice, this translates to meditation upon the heart, not as a physical organ but as a center of consciousness. What must be sought is not in external texts but in the depth of our own being; that is the true anveṣaṇa (investigation).