अन्तर उपपत्तेः ॥ १३ ॥
antara upapatteḥ || 13 ||
antaraḥ—Inside (the eye); upapatteḥ—on account of the appropriateness of (attributes).
13. (The person) inside (the eye is Brahman) on account of (the attributes mentioned therein) being appropriate (only to Brahman).
“This person that is seen in the eye is the self. This is immortal and fearless; this is Brahman” (Chh. 4. 15. 1).
The question is whether the person referred to here is the reflection of a person in the eye, or the individual soul, or the sun, which helps sight, or Brahman. The Sutra says that this person in the eye is Brahman, because the qualities, ‘immortal’, ‘fearless’, etc., mentioned here with respect to that person can be true only of Brahman, and they cannot be otherwise explained away.