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- For the actual time recorded, click on "Paper Statistics" above.
Write-up2 (as at 17/08/2018 17:35:31): Dicephalus
- There are several related pathological conditions in which the number of animals and the number of individuals may fail to align. In sequence of severity of the “condition”:-
- Conjoined Twins: Wikipedia: Conjoined Twins. Varies from a fairly loose conjunction of individuals, who may be separated, to more severe forms with shared organs and limbs. This article is of interest not least because it discusses the issue of fission versus fusion, with the latter now the favourite suggestion.
- Polycephaly: Wikipedia: Polycephaly. Animals or humans with apparently more than one head. Dicephaly is the limiting case. Usually an extreme version of conjunction.
- Diprosopus: Wikipedia: Diprosopus. Animals (including humans – see Link & Link; see Link for Janus cats) with two faces. There may be one or two brains, but only one skull. The important thing – and what differentiates the diprosopus from the dicephalus – is that there is much less duplication of body parts, so it is very much two brains sharing one body – though it can also be the relatively superficial – though tragic – case of one brain, one body and two faces.
- All these situations – and in particular the paradigm case of dicephalus, wherein it appears that we have a (human) animal with two heads – are often cited as a prima facie problems for Animalism4.
- The claim is that while we have multiple persons5, we only have a single animal6, so the animalist claim that persons are numerically identical to their organisms7 is false.
- Of course, the above claim is somewhat bald. Animalism8 - at least in the form expounded by Eric Olson - has no truck with psychology as necessary for our persistence. While Olson often refers to “people” this is just shorthand for “some of us9”, rather than “persons”, the plural of person.
- So, if the animalist claim is that we are human animals, then the question is – in the case of dicephalus and related conditions – how many of us are present, and how many human animals are present. Animalism need the numbers to be equal.
- The cases under consideration have the advantage over standard Thought Experiments10, in that they are real-life cases. What is actual must be possible, and a standard argument against TEs is thereby avoided – namely that some of them, at least, whatever our intuitions may say, may not in fact be possible because the TEs are under-described.
- That said, there’s still a temptation to push the boundaries, and to consider cases in this general area that are not actual, yet are not quite as science-fiction as the usual TEs.
- Cases of dicephalus are fairly rare, and often one “twin” is degenerate so it’s not clear that we have two persons or two of “us”. However, the case of the dicephalus twins, Abigail and Brittany Hensel, where one body appears to be coordinated by two brains (see Abigail and Brittany Hensel, and probably more “official” sites – see Wikipedia: Abigail and Brittany Hensel for instance) shows that this is not necessarily the case. Here we definitely have two persons, but maybe only one animal. This is probably a real-life case of either incomplete fission11 or of fusion12.
- There are two issues with these cases:-
- How should they be best described?
- How should the animalist respond?
- I need to research this further, but it seems to me that we have a sliding scale of pathological cases – from that of Siamese twins (who are often fairly loosely connected, and can often be surgically separated) to the much more extreme cases of diprosopus.
- I presume, also, that we can have both fission and fusion.
- In the case of (incomplete) fission, the twins will be identical, as the situation is one where the twinning process has not completed.
- But (I imagine) we can also have a case of fusion, where the twin-embryos – whether identical or fraternal – that were separate have subsequently partially fused.
- The most likely response from the animalist is that the dicephalus is not a single organism, but two organisms that share some body-parts.
- The force of the arguments in this kind of case depends on “relevant similarity” – if the dicephalus-case is sufficiently similar to the general case, it can be used to show things about the general case. But this claim can be rejected.
- In the case of diprosopus, it is more difficult to claim that there are two organisms. Now – in practice – there are never two persons either (as all the 30-odd cases recorded since 1860, the condition has proved quickly fatal, so there are no persons present). But this might not always be so. So, Lynne Rudder Baker might claim that the rudimentary persons are indeed persons – as there is a possibility that they would develop into robust persons. Failing that, it might be the case in the future that there is a case where the diprosopus survives to develop personality.
- For a page of Links13 to this Note, Click here.
- Works on this topic that I’ve actually read14, include15 the following:-
- "Blatti (Stephan) - Animalism, Dicephalus, and Borderline Cases", Blatti
- "Blatti (Stephan), Ed. - The Lives of Human Animals", Blatti
- "Blatti (Stephan) - Animalism and its Implications", Blatti
- "Hershenov (David) - Countering the Appeal of the Psychological Approach to Personal Identity", Hershenov
- "Liao (S. Matthew) - The Organism View Defended", Liao
- "Shoemaker (David) - Personal Identity and Immortality", Shoemaker
- "Shoemaker (David) - Personal Identity, Rational Anticipation, and Self-Concern", Shoemaker
- "Wilson (Jack) - Beyond Horses and Oak Trees: A New Theory of Individuation for Living Entities", Wilson
- A reading list (where not covered elsewhere) might start with:-
- "Barilan (Y. Michael) - One or Two: An Examination of the Recent Case of the Conjoined Twins from Malta", Barilan
- "Campbell (Tim) & McMahan (Jeff) - Animalism and the Varieties of Conjoined Twinning", Campbell & McMahan
- "Hershenov (David) - Problems with a Constitution Account of Persons", Hershenov
- "Hershenov (David) - Shoemaker's Problem of Too Many Thinkers", Hershenov
- "Koch-Hershenov (Rose J.) - Conjoined Twins and the Biological Account of Personal Identity", Koch-Hershenov
- "Olson (Eric) - The Metaphysical Implications of Conjoined Twining", Olson
- "Reid (Mark D.) - A Case in Which Two Persons Exist in One Animal", Reid
- "Snowdon (Paul) - Animalism and the Unity of Consciousness", Snowdon
- This is mostly a place-holder16.
- This is the write-up as it was when this Abstract was last output, with text as at the timestamp indicated (17/08/2018 17:35:31).
- Link to Latest Write-Up Note.
- A number of my philosophical Notes are “promissory notes” currently only listing the books and papers (if any) I possess on the topic concerned.
- I’ve decided to add some text – whether by way of motivation, or something more substantive – for all these identified topics related to my Thesis.
- As I want to do this fairly quickly, the text may be confused or show surprising ignorance.
- The reader (if such exists) will have to bear with me, and display the principle of charity while this footnote exists.
- If only a “non-updating” run has been made, the links are only one-way – ie. from the page of links to the objects that reference this Note by mentioning the appropriate key-word(s). The links are also only indicative, as they haven’t yet been confirmed as relevant.
- Once an updating run has been made, links are both ways, and links from this Notes page (from the “Authors, Books & Papers Citing this Note” and “Summary of Note Links to this Page” sections) are to the “point of link” within the page rather than to the page generically. Links from the “links page” remain generic.
- There are two sorts of updating runs – for Notes and other Objects. The reason for this is that Notes are archived, and too many archived versions would be created if this process were repeatedly run.
- Frequently I’ll have made copious marginal annotations, and sometimes have written up a review-note.
- In the former case, I intend to transfer the annotations into electronic form as soon as I can find the time.
- In the latter case, I will have remarked on the fact against the citation, and will integrate the comments into this Note in due course.
- My intention is to incorporate into these Notes comments on material I’ve already read rather than engage with unread material at this stage.
- I may have read others in between updates of this Note – in which case they will be marked as such in the “References and Reading List” below.
- Papers or Books partially read have a rough %age based on the time spent versus the time expected.
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