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Consciousness and Persons without Reductionism: Touching Churchland’s Nerve

June 22, 2018

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What am I? What is consciousness? Securing adequate answers to those questions would be tantamount to a discovery of the “holy grail” of neuroscience and philosophy. Some neuroscientists and philosophers believe that neurobiological facts alone are relevant to answering the foregoing questions. For instance, Patricia Churchland has argued in her recent book, Touching a Nerve, that naturalism provides a better account of the person and consciousness than dualism. For the sake of simplicity here, Churchland defines naturalism in terms of “only brain stuff” and dualism in terms of “soul stuff and brain stuff.” In the first two chapters, Churchland argues that, unlike naturalism, dualism has trouble accounting for the phenomena of neural dependence. For example, damage to the right parietal cortex can lead to visual neglect (i.e., a lack of awareness of stimulus contents associated with the left half of one’s visual field) and to somatoparaphrenia (i.e., a lack of awareness of the limbs on the left side of one’s body). Empirical data of this sort, Churchland claims, do not fit well with the dualist intuition that the person (or soul) is ontologically distinct from the brain, but that such data have greater consilience under the hypothesis of naturalism. Churchland then draws the sweeping inference that “there has been no advance since Descartes’s 350-year-old hypothesis” and that even deeply committed dualists these days are not even trying to formulate a testable hypothesis of soul. Churchland concludes that “soul theory is floundering because there is no soul” and that “probably the soul and the brain are one and the same.” Are persons (or souls) really nothing but brain stuff? Churchland thinks so. Toward the end of Touching a Nerve, Churchland also offers a naturalistic account of consciousness. She argues that current neurobiology is converging upon three properties central to consciousness: (1) that local and global connections are required for the integration of information; (2) that posterior events in the frontal areas are required for consciousness; and (3) that the central thalamus is required for enabling specific contents of consciousness. Of great theoretical importance, the common underlying mechanism of these three neurobiological properties, Churchland argues, is the synchronous activations of neurons: “The linkages, it is thought, may consist in synchrony in the activities of populations of neurons.” Churchland claims that recent data on “how anesthetics work provide significant support for this hypothesis” on grounds that anesthetics appear to cause a breakdown of the brain’s capacity to integrate information. This paper will argue that even if we grant that Cartesian dualism fails to account for the phenomena of neural dependence, it would not follow that no brand of dualism could. For Cartesian dualism is not the only dualist theoretical game in town. There are, in fact, recent non-Cartesian brands of dualism that have greater consilience than naturalism with respect to the deliverances of neuroscience regarding the nature of consciousness and persons, and that, moreover, some of those brands count as testable hypotheses in their own right. Further, it will be shown that Churchland’s purported common neurobiological mechanism of consciousness, namely neuronal synchrony, fails on several empirical grounds. For example, neuronal synchrony actually strengthens during anesthetic-induced unconsciousness. Finally, the paper will briefly sketch out a new non-Cartesian hypothesis of dualism, including its testability in light of recent data culled from neuroanesthesia, with the conclusion that non-Cartesian dualism fits the data of consciousness and persons far better than naturalism.

Keywords:
Nature of the soul; Dualism verses naturalism; Neurobiology; Foundations of consciousness