<p>The question title reads:</p>
<blockquote>
<p>Does the split brain disprove a materialistic mind?</p>
</blockquote>
<p>The simple answer being <strong>no</strong>, nothing disproves that - the brain harbors the mind (<em>e.g.</em>, <a href="https://www.scientificamerican.com/article/uncovering-brainscams/" rel="nofollow noreferrer">Lilienfeld &amp; Arkowitz, 2008)</a>.</p>
<p>Now you mention that two hypotheses on split-brain patients are false, namely...</p>
<blockquote>
<ol>
<li><p><a href="http://www.medicalnewstoday.com/releases/315508.php" rel="nofollow noreferrer">Both [hemispheres] gain their own conscious mind.</a></p>
</li>
<li><p><a href="https://cogsci.stackexchange.com/a/76/1002">Only one [hemisphere] has a conscious mind</a>.</p>
</li>
</ol>
</blockquote>
<p>...and I agree with them being incorrect hypotheses as suggested in the linked pages.</p>
<p>Now you proceed with...</p>
<blockquote>
<p>[Does a] single conscious mind operates across both [hemispheres ?]</p>
</blockquote>
<p>Importantly, you state yourself that...</p>
<blockquote>
<p>[...] there are [...] other pathways between the hemispheres besides the corpus callosum - such as thalamocortical circuits [...] and those via the midbrain and brainstem [...].</p>
</blockquote>
<p>So from my perspective, up until now you have answered your own question whether one single mind operates across two hemispheres in split-brain patients. Anyway, to illustrate some additional interhemispheric commissures besides the callosal pathway, see Fig. 1. This shows that '<em>split-brains</em> are in fact not entirely split; only the main causeway is severed.</p>
<p>Now there are wild stories about split-brain patients having a dual consciousness, including the paper by <a href="http://web.a.ebscohost.com/ehost/pdfviewer/pdfviewer?sid=91fbb01d-0577-4a71-b235-e225cf5c281f%40sessionmgr4001&amp;vid=1&amp;hid=4209" rel="nofollow noreferrer">Joseph (1998)</a> where the author speculates that one of his patients &quot;<em>...was possessed of two minds</em>&quot; based on the frustrations experienced by this person because his motor skills were erratic. <a href="http://ajp.psychiatryonline.org/doi/pdf/10.1176/ajp.101.5.594" rel="nofollow noreferrer">Andrew &amp; Akelaitis (1945)</a> explain that split-brain patients can display <em>diagnostic dyspraxia</em> by an unbalanced inhibitory influence of the dominant hemisphere over the non-dominant side, explaining the uncoordinated behavior on the non-dominant side. These symptoms generally diminish over time, as the brain deploys alternative inter-hemispheric routing of communications.</p>
<p><a href="https://i.sstatic.net/g40di.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/g40di.jpg" alt="brain" /></a><br />
<sup>Fig. 1. Interhemispheric pathways are indicated by numbers 1, 2, 3 and 4. source: <a href="https://i.sstatic.net/g40di.jpg" rel="nofollow noreferrer">Urbanski <em>et al</em>. (2014)</a></sup></p>
<p><sub><strong>References</strong><br />
<strong>-</strong> <a href="http://ajp.psychiatryonline.org/doi/pdf/10.1176/ajp.101.5.594" rel="nofollow noreferrer">Andrew &amp; Akelaitis (1945) <em>Am J Psychiatr</em>; <strong>101</strong>(5): 594-9</a><br />
<strong>-</strong> <a href="http://web.a.ebscohost.com/ehost/pdfviewer/pdfviewer?sid=91fbb01d-0577-4a71-b235-e225cf5c281f%40sessionmgr4001&amp;vid=1&amp;hid=4209" rel="nofollow noreferrer">Joseph, <em>J Clin Psychol</em> (1988); <strong>44</strong>(5): 770-9</a><br />
<strong>-</strong> <a href="https://www.scientificamerican.com/article/uncovering-brainscams/" rel="nofollow noreferrer">Lilienfeld &amp; Arkowitz, <em>Sci Am Mind</em> (February 2008)</a><br />
<strong>-</strong> <a href="https://i.sstatic.net/g40di.jpg" rel="nofollow noreferrer">Urbanski <em>et al</em>., *Front Integr Neurosci (2014)</a></sub></p>

CC BY-SA 3.0
2017-04-20T15:09:29.170Z
That alternate pathways are eventually established does not address the situation immediately after the brain is severed.  If these pathways do not yet exist, yet the conscious mind is still unified across both halves, then this is evidence for an immaterial mind.
yters
CC BY-SA 3.0
2017-04-20T21:20:08.390Z
@yters - they exist beforehand; it is thought additional links get established once severed.
AliceD
CC BY-SA 3.0
2017-04-23T00:06:39.890Z
I mistyped.  The second sentence should read: If these pathways *are not yet established*, yet the conscious mind is still unified across both halves, then this is evidence for an immaterial mind.
yters
CC BY-SA 4.0
2017-04-20T08:45:12.740Z
2022-08-02T11:16:05.530Z
2022-08-02T11:16:05.530Z
AliceD
<p>According to materialism, the conscious mind is the product of the brain.  Thus, if the brain is split in half such that the two hemispheres cannot communicate with each other, then there are three possibilities:</p>

<ol>
<li>Both hemispheres gain their own conscious mind.</li>
<li>Only one hemispheres has a conscious mind.</li>
<li>A single conscious mind operates across both hemispheres.</li>
</ol>

<p>Within a materialistic paradigm, #3 is impossible.  There cannot be unified control without communication between the two hemispheres.</p>

<p>Option #1 is false according to this <a href="http://www.medicalnewstoday.com/releases/315508.php" rel="nofollow noreferrer">article</a>,</p>

<blockquote>
  <p>A new research study contradicts the established view that so-called
  split-brain patients have a split consciousness. Instead, the
  researchers behind the study, led by UvA psychologist Yair Pinto, have
  found strong evidence showing that despite being characterised by
  little to no communication between the right and left brain
  hemispheres, split brain does not cause two independent conscious
  perceivers in one brain. Their results are published in the latest
  edition of the journal Brain.</p>
</blockquote>

<p>and this <a href="https://cogsci.stackexchange.com/a/14023/1002">answer</a>.</p>

<blockquote>
  <p>So I conclude from [sic] this quick literature review that Joseph
  ascribes the presence of two minds based on something that can be
  explained at a more basic level, and hence by a more simple model,
  namely disinhibited motor control. Given the principle of parsimony, I
  conclude his observations were right, but that his conclusions were
  not.</p>
</blockquote>

<p>Option #2 is false according to this <a href="https://cogsci.stackexchange.com/a/76/1002">answer</a>.  The answer state consciousness does not transfer to one half, but continues to operate in both halves.</p>

<blockquote>
  <p>If by continuity you mean, "a feeling that I am who I was before the
  operation, (perhaps with some changes)", then it seems that each
  hemisphere would separately maintain continuity, in the same way
  patients after massive strokes and other sudden brain injuries don't
  usually feel "they are a different person".</p>
</blockquote>

<p>Thus, only option #3 is viable according to the available data.</p>

<p>If option #3 is indeed the only possible explanation, yet is impossible according to materialism, then the materialistic explanation for the conscious mind is false.</p>

<p>A fourth possibility is there is an alternative communication pathway that is not severed, as hinted at by this <a href="https://cogsci.stackexchange.com/a/616/1002">answer</a>.</p>

<blockquote>
  <p>Keep in mind that there are many other pathways between the
  hemispheres besides the Corpus Callosum - such as thalamocortical
  circuits, those via the midbrain and brainstem and of course external
  sensorimotor feedback.</p>
</blockquote>

<p>Is option #3 the only viable option, or do the halves somehow communicate in a different way?</p>

CC BY-SA 3.0
2017-04-18T20:23:50.610Z
_"or some implicit premise is false"_ ... there are hundreds of underlying premises hidden in these statements which all will boil down to debating the nature of consciousness. For example: _"If the two brain halves cannot communicate with each other, then the halves should generate two independent conscious minds"_; why would this be so? This contains a hidden premise along the lines of "any subsection of the brain gives rise to a conscious mind". In short, no, your argument does not sound valid at all (thus does not disprove a materialistic mind).
Steven Jeuris
CC BY-SA 3.0
2017-04-18T21:10:37.490Z
@StevenJeuris I've clarified the argument.
yters
CC BY-SA 3.0
2017-04-20T07:26:11.923Z
Why isn't _"4. There is no longer a conscious mind"_ in the list of options? Or a 'different' form of conscious mind, given that no clear definition of 'conscious mind' is given.
Steven Jeuris
CC BY-SA 3.0
2017-04-20T07:32:47.963Z
Also, your exclusion for option 1 and option 2 seem to contradict each other no? So you are using different lines of reasoning to aggregate into one conclusion, further indicating there are unclear underlying premises which you have not defined and seem to contradict each other. More concretely, your reason for excluding option 2 also seems to exclude option 3, why do you decide to keep that one? That said, I feel there is sufficient information in this question now (albeit some erroneous reasoning) for this to be answered, thus I reopened.
Steven Jeuris
CC BY-SA 3.0
2017-04-20T15:06:56.313Z
@StevenJeuris I should also add what a non-materialistic mind looks like.  This means the mind resides in a non-physical realm, and somehow can interact with different parts of the brain independently.  Thus, if the different brain parts can no longer communicate with each other, they can still all received communication from the same mind, and be synchronized under unified control.  The result is that falsifying #2 provides evidence for #3 under this theory of mind.
yters
CC BY-SA 3.0
2017-04-20T17:42:37.353Z
I understood that. The point is: you are cherry picking. If you subscribe to the answer provided to disprove option 2 ([as you linked to](https://cogsci.stackexchange.com/questions/40/if-someone-becomes-a-split-brain-patient-which-side-will-maintain-the-continu/76#76)), that same answer states _"Research by Turk et al. (2003) suggests it's just the left hemisphere, because only the left hemisphere has the 'interpreter' module."_, which conflicts with your option 3. I.e., your argument is not valid and requires further elaboration (define underlying premises, likely by refining definitions).
Steven Jeuris
CC BY-SA 3.0
2017-04-23T00:13:54.910Z
@StevenJeuris, Yes, that answer alternates positions between paragraphs.  The first paragraph is against option 2, the second paragraph (your cite) supports option 2, then the third paragraph seems to settle somewhere in the middle.  So, that answer is not as definitive as I would like, but based on the first paragraph the answer as a whole is weighted against option 2.
yters
<cognitive-modeling><neurophysiology><theory-of-mind><brain><pathology>
Does the split brain disprove a materialistic mind?
yters
# Does the split brain disprove a materialistic mind?

(Asked by: username_0 on 2017-03-18)

According to materialism, the conscious mind is the product of the brain. Thus, if the brain is split in half such that the two hemispheres cannot communicate with each other, then there are three possibilities:

1. Both hemispheres gain their own conscious mind.
2. Only one hemispheres has a conscious mind.
3. A single conscious mind operates across both hemispheres.

Within a materialistic paradigm, #3 is impossible. There cannot be unified control without communication between the two hemispheres.

Option #1 is false according to this [article](http://www.medicalnewstoday.com/releases/315508.php),

> A new research study contradicts the established view that so-called
> split-brain patients have a split consciousness. Instead, the
> researchers behind the study, led by UvA psychologist Yair Pinto, have
> found strong evidence showing that despite being characterised by
> little to no communication between the right and left brain
> hemispheres, split brain does not cause two independent conscious
> perceivers in one brain. Their results are published in the latest
> edition of the journal Brain.

and this [answer](https://cogsci.stackexchange.com/a/14023/1002).

> So I conclude from [sic] this quick literature review that Joseph
> ascribes the presence of two minds based on something that can be
> explained at a more basic level, and hence by a more simple model,
> namely disinhibited motor control. Given the principle of parsimony, I
> conclude his observations were right, but that his conclusions were
> not.

Option #2 is false according to this [answer](https://cogsci.stackexchange.com/a/76/1002). The answer state consciousness does not transfer to one half, but continues to operate in both halves.

> If by continuity you mean, "a feeling that I am who I was before the
> operation, (perhaps with some changes)", then it seems that each
> hemisphere would separately maintain continuity, in the same way
> patients after massive strokes and other sudden brain injuries don't
> usually feel "they are a different person".

Thus, only option #3 is viable according to the available data.

If option #3 is indeed the only possible explanation, yet is impossible according to materialism, then the materialistic explanation for the conscious mind is false.

A fourth possibility is there is an alternative communication pathway that is not severed, as hinted at by this [answer](https://cogsci.stackexchange.com/a/616/1002).

> Keep in mind that there are many other pathways between the
> hemispheres besides the Corpus Callosum - such as thalamocortical
> circuits, those via the midbrain and brainstem and of course external
> sensorimotor feedback.

Is option #3 the only viable option, or do the halves somehow communicate in a different way?

**Tags:** cognitive-modeling, neurophysiology, theory-of-mind, brain, pathology

> **Comments:**
> **username_1**: _"or some implicit premise is false"_ ... there are hundreds of underlying premises hidden in these statements which all will boil down to debating the nature of consciousness. For example: _"If the two brain halves cannot communicate with each other, then the halves should generate two independent conscious minds"_; why would this be so? This contains a hidden premise along the lines of "any subsection of the brain gives rise to a conscious mind". In short, no, your argument does not sound valid at all (thus does not disprove a materialistic mind).  
> **username_0**: @StevenJeuris I've clarified the argument.  
> **username_1**: Why isn't _"4. There is no longer a conscious mind"_ in the list of options? Or a 'different' form of conscious mind, given that no clear definition of 'conscious mind' is given.  
> **username_1**: Also, your exclusion for option 1 and option 2 seem to contradict each other no? So you are using different lines of reasoning to aggregate into one conclusion, further indicating there are unclear underlying premises which you have not defined and seem to contradict each other. More concretely, your reason for excluding option 2 also seems to exclude option 3, why do you decide to keep that one? That said, I feel there is sufficient information in this question now (albeit some erroneous reasoning) for this to be answered, thus I reopened.  
> **username_0**: @StevenJeuris I should also add what a non-materialistic mind looks like.  This means the mind resides in a non-physical realm, and somehow can interact with different parts of the brain independently.  Thus, if the different brain parts can no longer communicate with each other, they can still all received communication from the same mind, and be synchronized under unified control.  The result is that falsifying #2 provides evidence for #3 under this theory of mind.  
> **username_1**: I understood that. The point is: you are cherry picking. If you subscribe to the answer provided to disprove option 2 ([as you linked to](https://cogsci.stackexchange.com/questions/40/if-someone-becomes-a-split-brain-patient-which-side-will-maintain-the-continu/76#76)), that same answer states _"Research by Turk et al. (2003) suggests it's just the left hemisphere, because only the left hemisphere has the 'interpreter' module."_, which conflicts with your option 3. I.e., your argument is not valid and requires further elaboration (define underlying premises, likely by refining definitions).  
> **username_0**: @StevenJeuris, Yes, that answer alternates positions between paragraphs.  The first paragraph is against option 2, the second paragraph (your cite) supports option 2, then the third paragraph seems to settle somewhere in the middle.  So, that answer is not as definitive as I would like, but based on the first paragraph the answer as a whole is weighted against option 2.  

---

## 1 answers

### Answer by username_2 on 2017-04-20. Score: 6

The question title reads:

> Does the split brain disprove a materialistic mind?

The simple answer being **no**, nothing disproves that - the brain harbors the mind (*e.g.*, [Lilienfeld & Arkowitz, 2008)](https://www.scientificamerican.com/article/uncovering-brainscams/).

Now you mention that two hypotheses on split-brain patients are false, namely...

> 1. [Both [hemispheres] gain their own conscious mind.](http://www.medicalnewstoday.com/releases/315508.php)
> 2. [Only one [hemisphere] has a conscious mind](https://cogsci.stackexchange.com/a/76/1002).

...and I agree with them being incorrect hypotheses as suggested in the linked pages.

Now you proceed with...

> [Does a] single conscious mind operates across both [hemispheres ?]

Importantly, you state yourself that...

> [...] there are [...] other pathways between the hemispheres besides the corpus callosum - such as thalamocortical circuits [...] and those via the midbrain and brainstem [...].

So from my perspective, up until now you have answered your own question whether one single mind operates across two hemispheres in split-brain patients. Anyway, to illustrate some additional interhemispheric commissures besides the callosal pathway, see Fig. 1. This shows that '*split-brains* are in fact not entirely split; only the main causeway is severed.

Now there are wild stories about split-brain patients having a dual consciousness, including the paper by [Joseph (1998)](http://web.a.ebscohost.com/ehost/pdfviewer/pdfviewer?sid=91fbb01d-0577-4a71-b235-e225cf5c281f%40sessionmgr4001&vid=1&hid=4209) where the author speculates that one of his patients "*...was possessed of two minds*" based on the frustrations experienced by this person because his motor skills were erratic. [Andrew & Akelaitis (1945)](http://ajp.psychiatryonline.org/doi/pdf/10.1176/ajp.101.5.594) explain that split-brain patients can display *diagnostic dyspraxia* by an unbalanced inhibitory influence of the dominant hemisphere over the non-dominant side, explaining the uncoordinated behavior on the non-dominant side. These symptoms generally diminish over time, as the brain deploys alternative inter-hemispheric routing of communications.

[![brain](https://i.sstatic.net/g40di.jpg)](https://i.sstatic.net/g40di.jpg)  
Fig. 1. Interhemispheric pathways are indicated by numbers 1, 2, 3 and 4. source: [Urbanski *et al*. (2014)](https://i.sstatic.net/g40di.jpg)

**References**  
**-** [Andrew & Akelaitis (1945) *Am J Psychiatr*; **101**(5): 594-9](http://ajp.psychiatryonline.org/doi/pdf/10.1176/ajp.101.5.594)  
**-** [Joseph, *J Clin Psychol* (1988); **44**(5): 770-9](http://web.a.ebscohost.com/ehost/pdfviewer/pdfviewer?sid=91fbb01d-0577-4a71-b235-e225cf5c281f%40sessionmgr4001&vid=1&hid=4209)  
**-** [Lilienfeld & Arkowitz, *Sci Am Mind* (February 2008)](https://www.scientificamerican.com/article/uncovering-brainscams/)  
**-** [Urbanski *et al*., \*Front Integr Neurosci (2014)](https://i.sstatic.net/g40di.jpg)

> **Comments:**
> **username_0**: That alternate pathways are eventually established does not address the situation immediately after the brain is severed.  If these pathways do not yet exist, yet the conscious mind is still unified across both halves, then this is evidence for an immaterial mind.  
> **username_2**: @username_0 - they exist beforehand; it is thought additional links get established once severed.  
> **username_0**: I mistyped.  The second sentence should read: If these pathways *are not yet established*, yet the conscious mind is still unified across both halves, then this is evidence for an immaterial mind.  

---

