Text 34]]
Nature, the Enjoyer, and Consciousness
659
PURPORT
The air enters into water, mud, stool and whatever else is there; still it does not mix with anything. Similarly, the living entity, even though situated in varieties of bodies, is aloof from them due to his subtle nature. Therefore it is impossible to see with the material eyes how the living entity is in contact with this body and how he is out of it after the destruction of the body. No one in science can ascertain this.
TEXT 34
यथा प्रकाशयत्येकः कृत्स्नं लोकमिमं रविः । 
    क्षेत्रं क्षेत्री तथा कृत्स्नं प्रकाशयति भारत ॥३४॥
yathā prakāśayaty ekaḥ kṛtsnaṁ lokam imaṁ raviḥ kṣetraṁ kṣetrī tathā kṛtsnaṁ prakāśayati bhārata
yathā —as;  prakāśayati —illuminates;  ekaḥ —one;  kṛtsnam —the whole;  lokam —universe;  imam —this;  raviḥ —the sun;  kṣetram —this body;  kṣetrī —the soul;  tathā —similarly;  kṛtsnam —all;  prakāśayati —illuminates;  bhārata —O son of Bharata.
TRANSLATION
O son of Bharata, as the sun alone illuminates all this universe, so does the living entity, one within the body, illuminate the entire body by consciousness.
PURPORT
There are various theories regarding consciousness. Here in  Bhagavad-gītā  the example of the sun and the sunshine is given. As the sun is situated in one place, but is illuminating the whole universe, so a small particle of spirit soul, although situated in the heart of this body, is illuminating the whole body by consciousness. Thus consciousness is the proof of the presence of the soul, as sunshine or light is the proof of the presence of the sun.