SB 6.4.25
deho ’savo ’ksa manavo bhuta-matram
atmanam anyam ca viduh param yat
sarvam puman veda gunams ca taj-jño
na veda sarva-jñam anantam ide
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Because they are only matter, the body, the life airs, the external and internal senses, the five gross elements and the subtle sense objects [form, taste, smell, sound and touch] cannot know their own nature, the nature of the other senses or the nature of their controllers. But the living being, because of his spiritual nature, can know his body, the life airs, the senses, the elements and the sense objects, and he can also know the three qualities that form their roots. Nevertheless, although the living being is completely aware of them, he is unable to see the Supreme Being, who is omniscient and unlimited. I therefore offer my respectful obeisances unto Him.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Material scientists can make an analytical study of the physical elements, the body, the senses, the sense objects and even the air that controls the vital force, but still they cannot understand that above all these is the real spirit soul. In other words, the living entity, because of his being a spirit soul, can understand all the material objects, or, when self-realized, he can understand the Paramatma, upon whom yogis meditate. Nevertheless, the living being, even if advanced, cannot understand the Supreme Being, the Personality of Godhead, for He is ananta, unlimited, in all six opulences.