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Personal Identity

Brain Criterion

(Text as at 06/07/2023 00:43:12)

Plug Note¹

• Thesis Text:
  1. The question is whether the brain is the be-all and end-all of the matter of personal identity for human persons².
  2. This view seems to be presupposed by those ethicists who espouse the (whole or part) brain death³ criterion for death⁴. There will be some overlap between this note and that on brain death.
  3. It is acknowledged by most that – conceptually at least – there can be persons⁵ that are not humans (ie. not members of the species homo sapiens) – whether these persons be non-human animals, computers, God, angels, aliens or whatever. Non-animals presumably have no brains, though aliens presumably have a brain-analogue, so brains cannot be identity-criteria for personhood as such (indeed, we might argue that there are no criteria for persons as such₆). But for animal-persons (human or otherwise), the brain seems to occupy a central place, both as the seat of psychology (in the absence of an immaterial soul⁷) and as the regulator of the body.
  4. So, the story would go, X is the same person as Y iff₈ X has the same brain as Y.
  5. The trouble is – even if this claim is along the right lines – we can press matters further, and ask whether the whole brain is strictly necessary. If what impresses us is a brain-based psychological view⁹, when what we imagine is “really the minimal me” is the pair of psychology-bearing cerebral hemispheres, then we might imagine (as some philosophers have) a case of fission¹⁰, where – after equalising the hemispheres in psychological potency, we transplant¹¹ one into another body lacking both hemispheres. Or, without needing anything so radical, we sever the corpus callosum in a commissurotomy¹², thereby (on this view) creating two persons in one body.
  6. However, if we are animalists¹³,¹⁴ wondering what the “minimal animal” is, and it’s the command-and-control functions of the brain that impress us, then the paring-down process might₁₅ be able to do without the cerebral hemispheres (or at least the psychology-bearing parts) altogether. So, brain-based views from different perspectives might come to different conclusions about the importance of the cerebral hemispheres – one view might make them essential, the other irrelevant to questions of identity (if not to “what matters¹⁶”). It is an empirical question whether the brain-stem can be divided, and hence whether a brain-based animalist approach is also subject to worries₁₇ about fission.
  7. Anyway, the appropriateness of the Brain criterion of personal identity depends on what we are¹⁸– in particular whether we are (most fundamentally, or in the sense of numerical identity¹⁹, which is not the same thing) human animals or persons constituted by²⁰ them (or various other things).
  8. Only if we believe that we are (identical to) brains²¹ will we adopt the brain criterion (though see Mark Johnston on Human Beings²²).

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  Further Remarks
  1. There will naturally be some overlap on this topic with the topics of
     • Brains²³ and
     • Criteria of Identity²⁴

References

• Relevant Works cited above:
  1. "Johnston (Mark) - Human Beings", 1987, Write-Up Note²⁵, Annotations, Internal PDF Link, Read
  2. "Merricks (Trenton) - There Are No Criteria For Identity Over Time", 1998, Internal PDF Link
• For a page of Links²⁶ to this Note, Click here. Slim pickings.
• Works on this topic that I’ve actually read²⁷, include the following:-
  • General:
    1. "Garrett (Brian) - Criteria of Personal Identity", 1998
    2. "Gert (Bernard), Lizza (John), Youngner (Stuart) & Chiong (Winston) - Matters of 'Life' and 'Death'", 2006, Annotations, Internal PDF Link
    3. "Johnston (Mark) - Human Beings", 1987, Write-Up Note²⁸, Annotations, Internal PDF Link, Footnote₂₉
    4. "Manninen (Tuomas) - Review of Alva Noe's 'Out of Our Heads: Why You Are Not Your Brain'", 2009, External Link
    5. "Noonan (Harold) - An Initial Survey", 2003, Annotations
    6. "Olson (Eric) - What Are We? Brains", 2007, Write-Up Note³⁰, Internal PDF Link
    7. "Parfit (Derek) - Nagel's Brain", 1986
    8. "Snowdon (Paul) - The Self and Personal Identity", 2009, Write-Up Note³¹
    9. "Thomas (Janice L.) - The bodily criterion", 2000
• A further reading list might start with:-
  • General:
    1. "Cockburn (David) - The Mind, the Brain and the Face", 1985, Internal PDF Link
    2. "Feinberg (Todd) - Our Brains, Our Selves", 2006, Internal PDF Link
    3. "Hershenov (David) - Who Doesn't Have a Problem of Too Many Thinkers?", 2013, External Link, Internal PDF Link, Read = 17%
    4. "Merricks (Trenton) - There Are No Criteria For Identity Over Time", 1998, Internal PDF Link
    5. "Noe (Alva) - Out of Our Heads: Why You Are Not Your Brain, and Other Lessons from the Biology of Consciousness", 2009, Book, Read = 8%
    6. "Parfit (Derek) - Persons, Bodies, and Human Beings", 2007, Internal PDF Link, Read = 7%
    7. "Tzinman (Rina) - Against the Brainstem View of the Persistence of Human Animals", 2016, Internal PDF Link, Read = 8%

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• For a list of Works that have been considered, but have missed the cut for inclusion in this Section of my Thesis, see the following:-
  1. Read: No items to list.
  2. Further Reading: No items to list.
• This is mostly a place-holder³².

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In-Page Footnotes:

Footnote 6:

1. Hasn’t someone said this? Who? Wiggins?
2. This is not to be confused with there being no criteria for identity – ie. for the relation itself – which is due to Merricks (eg. in "Merricks (Trenton) - There Are No Criteria For Identity Over Time").

Footnote 8:

1. And, of course, “X and Y are both persons”, to cover the case where the brain is insufficient to support the property of personhood.

Footnote 15:

1. Much of this discussion has empirical aspects to it, and depends on the capabilities of real brains – though we might get into the choppy waters of more intricate TEs, and wonder what might be the case if the biology went differently – but then we would most likely not be talking about our identity criteria, but of some other being.

Footnote 17:

1. These worries about fission are essentially set to rest by adopting a perdurantist account of persistence.
2. But, some consider the costs (mainly semantic, I think) of adopting this approach are too great.

Footnote 29:

• Johnston thinks we are human beings, but – when push comes to shove – we would survive as brains, so the criteria of our identity are – for Johnston – brain based.

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Table of the Previous 8 Versions of this Note:

Date	Length	Title
20/09/2022 11:24:00	5913	Brain Criterion
11/04/2022 00:01:26	5532	Brain Criterion
07/02/2021 19:46:34	5339	Brain Criterion
04/12/2019 23:36:58	4896	Brain Criterion
14/03/2018 10:07:41	5786	Brain Criterion
03/02/2018 18:44:38	5454	Brain Criterion
14/07/2013 23:02:24	3802	Brain Criterion
25/05/2010 14:58:34	84	Brain Criterion

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Note last updated	Reading List for this Topic	Parent Topic
06/07/2023 00:43:12	Brain Criterion	Logic of Identity

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Summary of Notes Referenced by This Note

Animalism	Animalists	Awaiting Attention (Personal Identity)	Brain	Brain Death
Brain Transplants	Commissurotomy	Constitution	Criteria of Identity	Death
Fission	Human Beings	Human Persons	Johnston - Human Beings	Note Links Explanation
Numerical Identity	Olson - What Are We? Brains	Perdurantism	Person	Plug Note Apologia
Psychological View	Snowdon - The Self and Personal Identity	Souls	Thought Experiments	What are We?
What Matters	Wiggins	Works Read - Explanation

To access information, click on one of the links in the table above.

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Summary of Notes Citing This Note

Baker - Personal Identity Over Time	Brain	Brain Death	General Surveys	Mereology
Olson - What Are We? Animals, 2	PID Note, Book & Paper Usage, 2, 3	Snowdon - The Self and Personal Identity	Thesis - Chapter 01 (Introduction)	Thesis - Chapter 02 (What are We?), 2, 3, 4, 5, 6
Thesis - Chapter 07 (The Constitution View and Arguments for It)	Thesis - Current Stance	Thesis - Personal Identity, 2, 3, 4, 5	Website Generator Documentation - Functors, 2, 3, 4, 5, 6

To access information, click on one of the links in the table above.

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Authors, Books & Papers Citing this Note

Author	Title	Medium	Extra Links	Read?
Baker (Lynne Rudder)	Personal Identity Over Time	Paper		Yes
Clark (Andy) & Kuhn (Robert Lawrence)	Aeon: Video - Andy Clark - Virtual immortality	Paper		Yes
Garrett (Brian)	Criteria of Personal Identity	Paper	2, 3	Yes
Gert (Bernard), Lizza (John), Youngner (Stuart) & Chiong (Winston)	Matters of 'Life' and 'Death'	Paper		Yes
Hershenov (David)	Who Doesn't Have a Problem of Too Many Thinkers?	Paper
Noonan (Harold)	An Initial Survey	Paper		Yes
Olson (Eric)	Animalism and the Remnant-Person Problem	Paper		Yes
Olson (Eric)	Psychology and Personal Identity	Paper		Yes
Olson (Eric)	What Are We? Animals	Paper	2	Yes
Olson (Eric)	Why We Need Not Accept the Psychological Approach	Paper		Yes
Parfit (Derek)	Persons, Bodies, and Human Beings	Paper
Potts (Michael)	A Requiem for Whole Brain Death: A Response to D. Alan Shewmon's ‘The Brain and Somatic Integration’	Paper
Snowdon (Paul)	Persons, Animals, Ourselves: Introduction	Paper		Yes
Snowdon (Paul)	The Self and Personal Identity	Paper		Yes
Thomas (Janice L.)	The bodily criterion	Paper	2, 3, 4	Yes
Todman (Theo)	Thesis - Brain	Paper		Yes
Todman (Theo)	Thesis - Brain Death	Paper		Yes
Todman (Theo)	Thesis - Chapter 01 (Introduction)	Paper		Yes
Todman (Theo)	Thesis - Chapter 02 (What Are We?)	Paper	2, 3, 4, 5, 6	Yes
Todman (Theo)	Thesis - Chapter 07 (The Constitution View and Arguments for It)	Paper		Yes
Todman (Theo)	Thesis - Current Position	Paper		Yes
Todman (Theo)	Thesis - General Surveys	Paper		Yes
Todman (Theo)	Thesis - Mereology	Paper		Yes
Todman (Theo)	Thesis - Personal Identity	Paper	2, 3, 4, 5

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References & Reading List

Author	Title	Medium	Source	Read?
Cockburn (David)	The Mind, the Brain and the Face	Paper - Cited	Philosophy, Vol. 60, No. 234 (Oct., 1985), pp. 477-493	No
Feinberg (Todd)	Our Brains, Our Selves	Paper - Cited	Daedalus, Vol. 135, No. 4, On Identity (Fall, 2006), pp. 72-80	No
Garrett (Brian)	Criteria of Personal Identity	Paper - Cited	Garrett - Personal Identity and Self-consciousness, 1998, Chapter 3	Yes
Garrett (Brian)	Personal Identity and Self-consciousness	Book - Cited (via Paper Cited)	Bibliographical details to be supplied	Yes
Gert (Bernard), Lizza (John), Youngner (Stuart) & Chiong (Winston)	Matters of 'Life' and 'Death'	Paper - Cited	The Hastings Center Report, Vol. 36, No. 3 (May - Jun., 2006), pp. 4-6	Yes
Johnston (Mark)	Human Beings	Paper - Cited	Journal of Philosophy, Volume 84, Issue 2 (Feb 1987), 59-83	Yes
Manninen (Tuomas)	Review of Alva Noe's 'Out of Our Heads: Why You Are Not Your Brain'	Paper - Cited	Metapsychology Online Reviews, Sep 15th 2009 (Volume 13, Issue 38)	Yes
Merricks (Trenton)	There Are No Criteria For Identity Over Time	Paper - Cited	Noûs, Vol. 32, No. 1 (Mar., 1998), pp. 106-124	No
Noe (Alva)	Out of Our Heads: Why You Are Not Your Brain, and Other Lessons from the Biology of Consciousness	Book - Cited	Noe (Alva) - Out of Our Heads: Why You Are Not Your Brain, and Other Lessons from the Biology of Consciousness	8%
Noonan (Harold)	An Initial Survey	Paper - Cited	Noonan - Personal Identity, 2003, Chapter 1	Yes
Noonan (Harold)	Personal Identity	Book - Cited (via Paper Cited)	Bibliographical details to be supplied	Yes
Olson (Eric)	Psychology and Personal Identity	Paper - Referencing	The Human Animal, September 1999, Chapter 1, pp. 7-21	Yes
Olson (Eric)	The Human Animal - Personal Identity Without Psychology	Book - Referencing (via Paper Referencing)	Bibliographical details to be supplied	Yes
Olson (Eric)	What are We? A Study of Personal Ontology	Book - Cited (via Paper Cited)	Bibliographical details to be supplied	Yes
Olson (Eric)	What are We? A Study of Personal Ontology	Book - Referencing (via Paper Referencing)	Bibliographical details to be supplied	Yes
Olson (Eric)	What Are We? Animals	Paper - Referencing	What Are We? A Study in Personal Ontology, Chapter 2 (November 2007: Oxford University Press.)	Yes
Olson (Eric)	What Are We? Brains	Paper - Cited	What Are We? A Study in Personal Ontology, Chapter 4 (November 2007: Oxford University Press.)	Yes
Olson (Eric)	Why We Need Not Accept the Psychological Approach	Paper - Referencing	The Human Animal, September 1999, Chapter 3, pp. 42-72	Yes
Parfit (Derek)	Nagel's Brain	Paper - Cited	Parfit - Reasons and Persons, Appendix D	Yes
Parfit (Derek)	Reasons and Persons	Book - Cited (via Paper Cited)	Bibliographical details to be supplied	Yes
Shand (John)	Central Issues of Philosophy	Book - Cited (via Paper Cited)	Bibliographical details to be supplied	35%
Snowdon (Paul)	Persons, Animals, Ourselves	Book - Referencing (via Paper Referencing)	Bibliographical details to be supplied	21%
Snowdon (Paul)	Persons, Animals, Ourselves: Introduction	Paper - Referencing	Snowdon (Paul) - Persons, Animals, Ourselves - Introduction	Yes
Snowdon (Paul)	The Self and Personal Identity	Paper - Cited	Shand (John) - Central Issues of Philosophy, Chapter 9	Yes
Thomas (Janice L.)	Mind and Person in the Philosophy of Religion	Book - Cited (via Paper Cited)	Bibliographical details to be supplied	Yes
Thomas (Janice L.)	The bodily criterion	Paper - Cited	Thomas (Janice L.) - Mind and Person in the Philosophy of Religion	Yes
Todman (Theo)	Thesis - Brain Criterion	Paper - By Subtopic		Yes

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1. Blue: Text by me; © Theo Todman, 2025

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