सुषुप्त्युत्क्रान्त्योर्भेदेन ॥ ४२॥
suṣuptyutkrāntyorbhedena || 42 ||
suṣupti-utkrāntyoḥ—In deep sleep and death; bhedena—as different.
42. Because of the Supreme Self being shown as different (from the individual soul) in the states of deep sleep and death.
In the sixth chapter of the Brihadaranyaka Upanishad, in reply to the question, “Which is that Self” (4.3.7), a lengthy exposition of the nature of the Self is given. The question is whether the Self is the Supreme Self or the individual soul. This Sutra says it is the Supreme Self. Why? Because it is shown to be different from the individual self in the state of deep sleep and at the time of death.
“This person, embraced by the supremely intelligent Self, knows nothing that is without or within” (Brih. 4. 3. 21),
which shows that in deep sleep the ‘person’ which represents the individual soul, is different from the Supreme Self, called here the supremely intelligent Self.
The ‘person’ is the individual soul, because the absence of the knowledge of external things and things within in deep sleep can be predicated only of the individual soul, which is the knower, and the supremely intelligent Self is Brahman because such intelligence can be predicated of Brahman only. Similarly at the time of death. Brih. 4. 3. 35 ). Therefore Brahman is the chief topic in this section. The extensive discourse on the individual soul in this section is not to establish its Jivahood, but to show that it is in reality not different from Brahman.