The explanatory ground of the brainbound view of consciousness: A reply to enactive embodied externalism

Enactivism argues that the brainbound view of consciousness lacks adequate explanatory grounds, claiming that the deep physiological and dynamical entanglement between brain and body undermines the idea that the brain alone constitutes the minimal realizing system for consciousness. This challenge has been most clearly articulated by Thompson and Cosmelli (2011), who appeal to the biological implausibility of the brain-in-a-vat thought experiment to argue that brain and body are explanatorily and metaphysically inseparable. Strategically sophisticated and persuasive, this challenge remains unanswered to date. In this paper, we address the enactive challenge and argue that it fails to undermine the brainbound view, as it is motivated within orthodox neuroscience. Specifically, we show that the brainbound position is grounded in a contrastive explanatory framework widely employed in the neuroscience of consciousness, whose aim is to identify difference-making factors relative to the contrast between the presence and absence of consciousness. Within this framework, the brain is singled out as explanatorily relevant not because it is assumed to be functionally or structurally separable from the body, but because contrastive neuroscientific evidence consistently identifies neural structures and processes as explanatory difference makers. We argue that contrastive explanation in principle permits explanatory separation without presupposing biological separability, rendering the impossibility of the brain-in-a-vat irrelevant to the explanatory foundations of the brainbound view. Future work must arbitrate between enactive and brainbound approaches on independent empirical, theoretical, and methodological grounds, irrespective of the (im)plausibility of this thought experiment.