tag:blogger.com,1999:blog-3891434218564545511.post7662018163392769940..comments2024-03-28T19:56:42.305-05:00Comments on Alexander Pruss's Blog: The human animal and the cerebrumAlexander R Prusshttp://www.blogger.com/profile/05989277655934827117noreply@blogger.comBlogger10125tag:blogger.com,1999:blog-3891434218564545511.post-39908611289737568782014-03-24T16:24:34.734-05:002014-03-24T16:24:34.734-05:00The topic of partial consciousness in the vegetati...The topic of partial consciousness in the vegetative state is mostly unkown, and there is controvwesy about it. I believe that the ascending activation system is required for dreaming, at least the type that occur in REM sleep. So the kind of consciousness that occurs when we dream probably could not occur in a cerebrum without a brainstem.<br /><br />Parts of the upper brainstem (midbrain, thalamus) such as the 'tegmentum' are so cross-connected with the cerebrum it is unlikely if the two are really separable in cognitive or motor function.Williamhttps://www.blogger.com/profile/12533263841520213358noreply@blogger.comtag:blogger.com,1999:blog-3891434218564545511.post-78048955251123677632014-03-24T14:14:49.473-05:002014-03-24T14:14:49.473-05:00Thanks, this is very interesting.
1. I have alway...Thanks, this is very interesting.<br /><br />1. I have always wondered about claims about what is necessary for consciousness in light of the fact that I have a hard time imagining how one would experimentally differentiate between the hypotheses (a) x is unconscious and (b) x is conscious but is unable to overtly react to what she is conscious of and is not recording anything to memory. <br /><br />Maybe there is a way. This question isn't something I pursued seriously.<br /><br />2. We're conscious at least some of the time while asleep. <br /><br />3. Consciousness is not required for a mental life, though I guess it is required for a flourishing human mental life.<br /><br />4. But I think the really important question is how substantive the contribution of the brain stem is. Is it more like the oxygen that is contributed by the circulatory system, or is it more substantive? <br /><br />Alexander R Prusshttps://www.blogger.com/profile/05989277655934827117noreply@blogger.comtag:blogger.com,1999:blog-3891434218564545511.post-91320537141188401762014-03-24T12:43:26.564-05:002014-03-24T12:43:26.564-05:00It's the "ascending arousal system" ...It's the "ascending arousal system" without which the rational animal cannot be awake. See Plum and Posner's textbook on stupor and coma, or for example here : http://www.ncbi.nlm.nih.gov/pubmed/23656993Williamhttps://www.blogger.com/profile/12533263841520213358noreply@blogger.comtag:blogger.com,1999:blog-3891434218564545511.post-61214355940470216332014-03-24T04:39:05.953-05:002014-03-24T04:39:05.953-05:00I did not know we had strong evidence the stem is ...I did not know we had strong evidence the stem is needed for consciousness. What is this evidence? Alexander R Prusshttps://www.blogger.com/profile/05989277655934827117noreply@blogger.comtag:blogger.com,1999:blog-3891434218564545511.post-16521079877800684722014-03-24T03:07:32.226-05:002014-03-24T03:07:32.226-05:00Biologically, the cerebrum cannot be conscious wit...Biologically, the cerebrum cannot be conscious without the brainstem, so a separation of cerebrum (somehow kept with living cells--how?) and the continuation of the body with just a brainstem produces just one person, cut in two parts, both parts comatose and moribund. <br /><br />A cerebrum (without brainstem) in a vat would be comatose unless some kind of prosthetic brainstem was added, and the result would be a machine hybrid which might be conscious, but I'm not sure.<br /><br />If your evil neurosurgeon does this twice, in order to swap cerebrums on the body-brainstem parts somehow, I suspect that identity follows cerebrum as far as the answer to "who am I" would go.<br /> Williamhttps://www.blogger.com/profile/12533263841520213358noreply@blogger.comtag:blogger.com,1999:blog-3891434218564545511.post-24349641089492926082014-03-23T15:29:31.935-05:002014-03-23T15:29:31.935-05:00Yeah, I suspect you can survive the destruction of...Yeah, I suspect you can survive the destruction of your cerebrum. <br /><br />So, yes, order matters. But that's not particularly surprising. You can survive having all your cells die and new ones grow back, but maybe not if it happens all at once.<br /><br />I don't think being the closest continuer *constitutes* identity. But typically, your closest continuer, as long as it's close enough, will be you.Alexander R Prusshttps://www.blogger.com/profile/05989277655934827117noreply@blogger.comtag:blogger.com,1999:blog-3891434218564545511.post-38570544358732387342014-03-23T14:05:07.052-05:002014-03-23T14:05:07.052-05:00What about a case in which the cerebrum is destroy...What about a case in which the cerebrum is destroyed while it is still inside the cranium of a human animal? Would destroying its cerebrum end the life of the animal, even if its functioning brain stem continued to coordinate metabolic activities? That seems implausible to me. Would you say, then, that in order to determine whether or not a cerebrum-less, apparently living, human body is an animal, it matters precisely HOW the original animal lost its cerebrum? Would this commit you to a sort of closest-continuer view?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3891434218564545511.post-60012374222263286172014-03-23T12:48:51.570-05:002014-03-23T12:48:51.570-05:00Jeremy:
I think it's not an animal. What tel...Jeremy:<br /><br />I think it's not an animal. What teleology it had was to support the functioning of the cerebrum. Not just the functioning of *a* cerebrum, but of *this* cerebrum.<br /><br />It's an interesting question whether it could get transplanted, though, and become the support for another cerebrum. (Unlike Michael, I don't think prosthetic limbs become part of the body.)Alexander R Prusshttps://www.blogger.com/profile/05989277655934827117noreply@blogger.comtag:blogger.com,1999:blog-3891434218564545511.post-84221363825949226872014-03-22T19:19:28.009-05:002014-03-22T19:19:28.009-05:00If the brain stem is left intact and functioning i...If the brain stem is left intact and functioning in the cerebrumless body, has the cerebrum transplant actually given rise to a new animal (the one "left behind")? If so, is it a rational animal? Would this be an instance of asexual human reproduction (like monozygotic twinning might be)? Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3891434218564545511.post-14841519338824477282014-03-21T14:19:55.735-05:002014-03-21T14:19:55.735-05:00"I think the animal goes with the cerebrum.&q..."I think the animal goes with the cerebrum."<br /><br />I agree, but there are at least two ways of interpreting this. One would be to say that (1) the animal becomes the cerebrum. Another would be to say that (2) the animal becomes that of which the cerebrum is a part--namely, the brain-vat composite. I incline to (2). I find it very hard to believe that I could be a cerebrum. I find it less hard to believe that I could be a brain-vat composite, for I tend to think of prosthetic limbs etc. as parts, not tools, of the organisms of which they are limbs.Michael Rabenberghttps://www.blogger.com/profile/14085883795963823041noreply@blogger.com