Kaṭha Upaniṣad 2.11

2.11

yat vidvadbhireva gantavyaṃ tasya sarvāpahnavasiddhatvena tadāptyupāyavairaḷyamāśaṅkya vastutastathātve'pyanādikālasiddhasvājñasvajñadṛṣṭimāśritya svātiriktandriyādyupalakṣitāvidyāpadatatkāryajātasya satyavyāvahārikaprātibhāsikatvādirūpeṇa vidyamānatvāttadālambya sthūlendriyādyārabhyāvyaktāntagatapratyagadhigamapūrvakaṃ parākāṣṭhāyamānabrahmamātrasvarūpamavagantuṃ śakyamitīdamārabhyate -- indriyebhya ityādinā | śṛṇomi paśyāmītyādipratyakprakāśadvārabhūtānīndriyāṇi tāvat sthūlāni tebhyaḥ svakāryebhya indriyebhyaḥ te hi parā arthāḥ śabdādisūkṣmatanmātrāḥ sthūlendriyāpekṣayā sūkṣmā mahāntaśca pratyagātmabhūtāśca | tebhyaḥ arthebhyaḥ sūkṣmaṃ mahat pratyagātmabhūtaṃ ca manaḥ saṃkalpādyārambhakam | tasmāt manaso'pi parā sūkṣmā mahattarā pratyagātmabhūtā hi buddhiḥ | adhyavasāyārambhakabhūtasūkṣmabuddherapi bodhābodhātmakāvyaktaprathamajatvena sarvaprāṇibuddhipratyagbhūtatvāt svakāryasarvamahatvācca ātmā mahān buddherapi paraḥ sūkṣmaḥ pratyagātmabhūtaścetyucyate |
iti ca śruteḥ smṛteśca | "yat gatvā na nivartante" iti yat tadanupapannaṃ gaterāgatipūrvakatvāt ityāśaṅkya sarvasya kevalabrahmamātratvādavagatireva gatirityupacaryate| indriyādyavyaktāntagateḥ pratyagbhāvaparisamāptatvāt pratīcaḥ parāgbhinnatvāt pratyagabhinnabrahmaṇaḥ parāgbhāvasāpekṣapratyagaikyagatasaviśeṣakalanāpahnave brahmamātraṃ siddhamityarthaḥ |