Is causal closure evidence for panpsychism?

Conversation
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Indeed. This just has to make me laugh:

It would be the same thing as if someone just took a chainsaw and cut the laptop in half and it still worked just fine. Like there’s something odd about this.

Well, Dr. Egnor, why not put that to the test? Just go ahead and cut one of your patient’s brain in half with a chainsaw, and tell us what happens. Will your patient’s mind still be working fine? Or will you, instead, be facing one massive lawsuit?

For a more intelligent discussion of these very interesting findings, see here:

Split-Brain: What We Know Now and Why This is Important for Understanding Consciousness - PubMed

An excerpt:

There are three, not-mutually exclusive, hypotheses concerning the mechanisms involved in, seemingly, preserved unity in the split-brain. The first notion is that information is transferred subcortically. The second idea is that ipsilateral motor control underlies unity in action control. The third idea claims that information transfer is based on varies forms of inter-hemispheric collaboration, including subtle behavioral cues. The first proposal (Corballis Corballis, Berlucchi, & Marzi, 2018; de Haan et al., 2019; Pinto, Lamme, & de Haan, 2017b; Pinto et al., 2017a; Savazzi et al., 2007; Mancuso, Uddin, Nani, Costa, & Cauda, 2019) suggests that the multitude of subcortical connections that are spared during surgery are responsible for the transfer of information. As was initially pointed out by Trevarthen (1968) and Trevarthen and Sperry (1973) and recently stressed by Pinto, de Haan, and Lamme (2017a) and Corballis et al. (2018), there are many commissures (white matter tracts that connect homologous structures on both sides of the central nervous system) and decussations (bundles that connect different structures on both sides) that link nuclei that are known to be involved in perceptual processing. The importance of these commisural connections for transferring visual information in split-brain patients has been highlighted by Trevarthen and Sperry (1973). Moreover, the role of these connections in a split-brain has recently been demonstrated by bilateral fMRI activations in the first somatosensory cortex, after unilateral stimulation of trunk midline touch receptors (Fabri et al., 2006) and in the second somatic sensory area after unilateral stimulation of hand pain receptors (Fabri, Polonara, Quattrini, & Salvolini, 2002). Uddin and colleagues used low-frequency BOLD fMRI resting state imaging to investigate functional connectivity between the two hemispheres in a patient in whom all major cerebral commissures had been cut (Uddin et al., 2008). Compared to control subjects, the patient’s interhemispheric correlation scores fell within the normal range for at least two symmetrical regions. In addition, Nomi and colleagues suggested that split-brain patients might rely particularly on dorsal and ventral pontine decussations of the cortico-cerebellar interhemispheric pathways as evidenced by increased fractional anisotropy (FA) on diffusion weighted imaging (Nomi, Marshall, Zaidel, Biswal, Castellanos, Dick, Uddin & Mooshagian, 2019). Interhemispheric exchange of information also seems to occur in the domain of taste sensitivity, activation of primary gustatory cortex in the fronto-parietal operculum was reported in both hemispheres after unilateral gustatory stimulation of the tongue receptors (Mascioli, Berlucchi, Pierpaoli, Salvolini, Barbaresi, Fabri, & Polonara, 2015). Note that patients may differ with respect to how many of these connections have been cut, and this might also explain some of the individual variance among patients. Moreover, in all patients subcortical structures remain intact. For instance, the superior colliculus is known to integrate visual information from both hemispheres and project information to both hemispheres (Meredith & Stein, 1986; Comoli et al., 2003). Such structures may support attentional networks, and may enable the right hemisphere to attend to the entire visual field. In turn, attentional unity could help in unifying cognitive and motor control, which may subserve ipsilateral motor control.

The second point concerns the ipsilateral innervation of the arms. Manual action is not strictly lateralized, and the proximal (but not the distal) parts of the arm are controlled bilaterally, although the ipsilateral contribution remains undetermined. This could explain why split-brain patients may respond equally well with both hands in certain experimental conditions (Corballis, 1995; Gazzaniga, Bogen, & Sperry, 1967; Pinto, de Haan, & Lamme, 2017a). First, there is substantial evidence that bilateral cortical activations can be observed during unilateral limb movements in healthy subjects. In addition, ipsilesional motor problems in arm control have been observed in patients with unilateral cortical injuries, and finally there is evidence from electrocorticography with implanted electrodes for localization of epileptic foci showing similar spatial and spectral encoding of contralateral and ipsilateral limb kinematics (Bundy, Szrama, Pahwa, & Leuthardt, 2018). While these observations argue convincingly for a role in action control by the ipsilateral hemisphere, they do not prove that a hemisphere on it’s own can purposefully control the movements of the ipsilateral hand. Thus, the role of ipsilateral arm-hand control in explaining split-brain findings is currently not settled.

The third hypothesis argues that in addition to whatever direct neural communication may exist between the hemispheres, they may inform one another via strategic cross-cueing processes (Volz & Gazzaniga, 2017; Volz et al., 2018). The split-brain patients underwent surgery many years prior to testing, and the separated perceptual systems have had ample time to learn how to compensate for the lack of commissural connections. For example, subtle cues may be given by minimal movements of the eyes or facial muscles, which might not even be visible to an external observer but are capable of encoding, for example, the location of a stimulus for the hemisphere that did not “see” it. A cross-cueing mechanism might also allow one hemisphere to convey to the other which one of a limited set of known items had been shown (Gazzaniga & Hillyard, 1971; Gazzaniga, 2013).

Finally, it is possible to entertain combinations of the different explanations. For instance, it is conceivable that in the subacute phase following split-brain surgery the hemispheres are ineffective in communicating with each other. During this initial phase, phenomena such as an “alien hand” - that is a hand moving outside conscious control of the (verbal) person - may be present. In the ensuing period, the patients may have learned to utilize the information that is exchanged via subcortical connections, ipsilateral motor control or cross-cueing to coordinate the processing of the two hemispheres. In such a way, the patient may counteract some of the effects of losing the corpus callosum.

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Except that three of those you named, “Plato, Descartes, Leibniz” lived centuries before science developed any understanding of brain processes. And the fourth and final, Thomas Nagel, has admitted to only engaging neuroscience at a superficial, ‘popular science’ publication, level.

They are thus absolutely worthless in impeaching Ron’s claim.

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Ron’s claim was in response to the following statement : Abstract thought cannot in principle arise wholly from brain processes. The words « in principle » in that statement makes you wrong.
Now, for the record, some neuroscientists have argued in books that the mind isn’t reducible to the brain. For example, Wilder Penfield and John Eccles.

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If you compare a brain with advanced Alzheimer’s, the physical atrophy is immediately apparent. The patient’s capability to reason, which previously might have been exceptional, may be tragically diminished to point of being unable to perform basic bodily self care. So my question is, tell me, if given the mind is not reducible to brain processes, where is, what is, the mind in these individuals? Why should plaques, or prions, or such physical impairments have any effect on minds which are endowed to abstract reasoning independent of the brain? The response always seems to come back as, well the mind is kinda involved with the brain somehow in a sorta way, but it really doesn’t mean anything. To me, that is not very compelling and is just sound of one hand clapping blather.

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I once had the joy and privilege of being at a forum/debate about the neuroscience of consciousness (at, I think, the Society for Neuroscience annual meeting in 1997 or 1998). Speakers included David Chalmers and, memorably, the neurobiologist Rodolfo Llinás of NYU. He asked the same (conceptually, IMO) question that Ron asks, in this unforgettable way:

What is this stuff “consciousness” that dissolves in local anesthetic?

I’m not really sure that this is a refutation of “mind isn’t reducible to brain”—I would say it isn’t—but it is a formidable challenge to those who want (or need) to harness consciousness in an effort to resurrect dead gods.

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Not quite the same thing, but …

“We don’t know much aout the human conscience, except that it is soluble in alcohol.”

— John Mortimer

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No they don’t Gilbert.

“Plato, Descartes, Leibniz, Thomas Nagel” had no clue what could “in principle arise wholly from brain processes” – the former three because they lived long before the principles of brain processes were established, the latter because he failed to familiarise himself with those principles in any depth.

They are therefore no more valid authorities on what brain processes can or cannot do in principle or in practice than they are on what nuclear fusion can or cannot do.

Lacking any information on (i) what their opinions on the topic were, (ii) what level of expertise they had in the field, and (iii) what the reception is (not merely was at the time) of these opinions by the wider scientific community, your further name-dropping is completely vacuous!

Let us briefly look at Wilder Penfield. He retired in 1960 – sixty five years ago Gilbert. That was more than a decade before the invention of the MRI and the first commercially-viable CT scanner. His was a time when neuroscience was still in its infancy. Think of all the advances in neuroscience since. Penfield is simply not a valid authority for what we know today about what brain processes can and cannot do in principle.

Eccles is only slightly better, having retired in 1975.

Further, you have given us no idea whatsoever what their specific opinions were – let alone whether those opinions stand up to neurological discoveries in the decades since they retired. What might have been considered a “sane” opinion before recent discoveries might well be considered “insane” if still held today.

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FWIW, I briefly discuss Penfield (or, more specifically, Egnor’s interpretation of his research) here:

A Neurosurgeon Argues That Mind Functions Are Immaterial. Badly. (Pt. 2)

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I’ve asked your question to Grok and here is how it concludes:

Proponents of the immateriality of the mind respond to the anesthesia argument by arguing that correlation between brain activity and consciousness does not prove identity, citing evidence like unified consciousness in split-brain patients (Sergent, Pinto), conscious veto power (Libet), and the subjective nature of experience (Penfield, Chalmers). They propose that the brain may mediate or filter consciousness without being its sole source, using analogies like the radio or filter theories. While anesthesia disrupts the neural correlates of consciousness, non-materialists argue this reflects a temporary disconnection, not proof that the mind is wholly reducible to the brain. The debate remains open, with materialists emphasizing mechanistic explanations and non-materialists highlighting the hard problem and empirical anomalies.

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This argument has never made sense to me. Exactly what is a “neural correlate” in this sense? If the correlation between neural activity is broken in these situations, this would mean that consciousness is now fully present and functioning in the absence of the sort of brain activity with which it is usually correlated. But that is not what happens.

It just gets us back to the original question: If consciousness is non-physical, where is it when someone is under general anaesthetic?

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This is the kinda sorta explanation that is so strained. Do people born persistently mentally impaired have some genius mind out there, but their transceiver have too much static? Can other brains tune into the same mind, say by reincarnation? Perhaps The Matrix is a historical documentary. Maybe we are just avatars for gamers on Zorg. If the brain is not the sole source, what is shared, and how does that work? Granted the immateriality of the mind, such questions are no longer frivolous, and those philosophers and authors who advocate for independent non-physical minds do not get a pass to just ignore neurological realities.

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The radio analogy may help here.
If I’m listening to a piece of music on my radio and the radio falls on the floor, it may be damaged to the point where I can no longer hear the music. But should I conclude that the signal encoding the music doesn’t exist anymore? We know the answers to this question, right?