CC Ādi 2.13

carma-cakṣe dekhe yaiche sūrya nirviśeṣa
jñāna-mārge laite nāre kṛṣṇera viśeṣa
Word for word: 
carma-cakṣe — by the naked eye; dekhe — one sees; yaiche — just as; sūrya — the sun; nirviśeṣa — without variegatedness; jñāna-mārge — by the path of philosophical speculation; laite — to accept; nāre — not able; kṛṣṇera — of Lord Kṛṣṇa; viśeṣa — the variety.
Translation: 
As with the naked eye one cannot know the sun except as a glowing substance, merely by philosophical speculation one cannot understand Lord Kṛṣṇa’s transcendental varieties.