Just as the soul may identify itself with the body or the life-force, it may also identify itself with the mind. There are several poises it may take in so doing. This occurs when the mental consciousness begins to experience self-awareness beyond the simple response and identification with the sense-impressions or feelings, emotions and reactions of the vital and physical body. Sri Aurobindo describes the various poises that arise for the soul identifying with the mind:
“The Soul identifies itself with this mental dynamo or station and says ‘I am this mind.’ And since the mind is absorbed in the bodily life, it thinks ‘I am a mind in a living body’ or, still more commonly, ‘I am a body which lives and thinks.’ It identifies itself with the thoughts, emotions, sensations of the embodied mind and imagines that because when the body is dissolved all this will dissolve, itself also will cease to exist. Or if it becomes conscious of the current of persistence of mental personality, it thinks of itself as a mental soul occupying the body whether once or repeatedly and returning from earthly living to mental worlds beyond; the persistence of this mental being mentally enjoying or suffering sometimes in the body, sometimes on the mental or vital plane of Nature it calls its immortal existence. Or else, because the mind is a principle of light and knowledge, however imperfect, and can have some notion of what is beyond it, it sees the possibility of a dissolution of the mental being into that which is beyond, some Void or some eternal Existence, and it says, ‘There I, the mental soul, cease to be.’ Such dissolution it dreads or desires, denies or affirms according to its measure of attachment to or repulsion from this present play of embodied mind and vitality.”
Whichever of these poises the Soul adopts, it has attached itself to the mind and posited its existence or non-existence on the corresponding existence or non-existence of the mind, whether on the mind’s own plane or existence, or linked to the vital and physical being it inhabits. This linking of the Soul to the mind is a false identification, as Bhrigu in the Taittiriya Upanishad learned when he, continuing his concentration at the suggestion of his father Varuna, finally recognized that Mind is not the final term or cause of existence.
Sri Aurobindo, The Synthesis of Yoga, Part Two: The Yoga of Integral Knowledge, Chapter 6, The Synthesis of the Disciplines of Knowledge, pp. 322-323