Adhyaya 8: Yogasthanas, Ashtanga Yoga, Pranayama-Siddhi, and Shiva-Dhyana leading to Samadhi
यत्प्रमाणगुहा प्रज्ञा मनस्तु मनुते यतः बृहत्त्वाद् बृंहणत्वाच्च ब्रह्मा ब्रह्मविदांवराः
yatpramāṇaguhā prajñā manastu manute yataḥ bṛhattvād bṛṃhaṇatvācca brahmā brahmavidāṃvarāḥ
Die Weisen, die Ersten unter den Kennern Brahmans, nennen Ihn „Brahmā“, weil in Ihm das verborgene Maß (pramāṇa) aller Erkenntnis ruht, weil der Geist nur auf seinem Grund zu denken vermag, und weil Er weit ist (bṛhat) und ausweitet (bṛṃhaṇa) — das Anwachsen von Sein und Wissen.
Suta Goswami (narrating traditional nirukti taught in the Purva-Bhaga context)
It frames the ultimate reality behind Linga worship as the inner “hidden measure” (pramāṇa-guhā) that enables all knowing; worship of the Linga is thus directed to Pati, the source of prajñā and the expansion of existence.
By describing the ground from which mind can think and by which being expands, it points to Shiva-tattva as Pati: vast, all-pervading consciousness that empowers cognition and unfolds the cosmos while remaining the inward cave of awareness.
The verse supports an inward Pashupata-oriented contemplation: turning the mind back to its source (the guhā of prajñā) while performing Linga-pūjā, recognizing cognition itself as dependent on the Lord.