Do you think a "brain in a vat," cut off from the body and outside world, could still be conscious?
NEWS | 27 February 2026
This article offers a careful and illuminating empirical probe into the classic “brain in a vat” problem by examining hemispherotomy patients—cases in which one cerebral hemisphere is biologically alive yet functionally disconnected from the body and the external world. Its central finding is both subtle and significant: even when neural networks remain surprisingly well organized, the isolated hemisphere most likely enters a sleep-like state rather than sustaining an independent stream of conscious experience. From the perspective of Advaita Vedānta, this conclusion is largely consonant with classical insights, while also revealing a deeper philosophical distinction. Advaita draws a sharp line between consciousness itself (cit or ātman) and the instruments through which experience is expressed—the body, senses, and mind. Consciousness, on this view, is not produced by neural or cognitive processes; it is self-luminous awareness, the unchanging witness in whose presence mental and sensory activities arise and subside. The brain–mind system functions as a medium for the manifestation of experience, not as its ontological source. Seen in this light, the article’s finding that organized neural structure can persist without conscious experience strongly supports the Vedāntic insight that organization is not identity. Structural or functional integrity alone does not amount to awareness. Advaita has long articulated this point through its analysis of the three states of experience—waking, dream, and deep sleep. Waking experience depends on active engagement between senses, body, and world. Dream shows that experience can arise without external sensory input, generated by the mind alone. Deep sleep represents the withdrawal of mental activity altogether—not the annihilation of awareness, but the absence of experiential content. By showing that neural structure can persist without conscious experience, the article clarifies the dependence of waking consciousness on bodily and environmental interaction, while unintentionally reinforcing Advaita’s distinction between awareness itself and the instruments through which it is expressed. Where the article and Advaita diverge is at the ontological level. Remaining within a physicalist framework, the article cautiously suggests that consciousness may fade when neural integration with body and world is lost. Advaita would reframe this claim: what fades is not consciousness itself, but its expression through the mind. In this way, the article usefully delineates the limits of neural organization in accounting for awareness and, perhaps unintentionally, echoes a central Vedāntic insight: science can describe the conditions under which experience appears, but the nature of consciousness itself may not be reducible to the structures that express it.
Author: Allison Parshall.
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