Brainstorms - Philosophical Essays on Mind and Psychology
Dennett (Daniel)
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Back Cover Blurb

  1. Invention, artificial intelligence, linguistics, dreams and free will are just some of the areas covered in Daniel C. Dennett's exhilarating investigation into the meaning of the mind and consciousness.
  2. In this superb collection of seventeen essays, he begins by exploring the concept of an intentional system and argues that intentional attributes such as desires, goals, beliefs and knowledge are purely mechanistic. After a thought-provoking assessment of developments in psychology, he considers the meaning of mental imagery, sensations, pain and other puzzling aspects of consciousness.
  3. Central to the overall discussion of the book is the question of whether psychology can support a vision of ourselves as moral agents, free to choose what we do and responsible for our actions. Out of the solutions proposed in these essays emerges a unifying theory of the mind.


Penguin Books, London, 1997

"Dennett (Daniel) - Brainstorms: Preface & Introduction"

Source: Dennett - Brainstorms - Philosophical Essays on Mind and Psychology

"Dennett (Daniel) - Intentional Systems"

Source: Dennett - Brainstorms - Philosophical Essays on Mind and Psychology, Chapter 1

Philosophers Index Abstract
    The author examines the concept of a system whose behavior can be (at least sometimes) explained and predicted by relying on ascriptions to the system of beliefs and desires. Three tactics or stances for prediction are distinguished: the physical, design, and intentional stances. Intentional stance predictions are shown to depend on an assumption of rationality or optimality of design, and it is claimed that some computers are already dealt with from this stance. Intentional stance predictions can be viewed as arising from a "theory of behavior", and the relation of intentional theories to others, especially skinnerian behaviorism, is described. The concept of an intentional system is finally shown to provide answers to several puzzles about belief: the normative nature of belief ascriptions and the problem of incorrigibility.

COMMENT: Part I. Intentional Explanation and Attributions of Mentality.

"Dennett (Daniel) - Reply to Arbib and Gunderson"

Source: Dennett - Brainstorms - Philosophical Essays on Mind and Psychology, Chapter 2

COMMENT: Part I. Intentional Explanation and Attributions of Mentality.

"Dennett (Daniel) - Brain Writing and Mind Reading"

Source: Dennett - Brainstorms - Philosophical Essays on Mind and Psychology, Chapter 3


"Dennett (Daniel) - Skinner Skinned"

Source: Dennett - Brainstorms - Philosophical Essays on Mind and Psychology, Chapter 4

COMMENT: Part II. The Nature of Theory in Psychology.

"Dennett (Daniel) - Why the Law of Effect Will Not Go Away"

Source: Dennett - Brainstorms - Philosophical Essays on Mind and Psychology, Chapter 5

COMMENT: Part II. The Nature of Theory in Psychology.

"Dennett (Daniel) - A Cure for the Common Code?"

Source: Dennett - Brainstorms - Philosophical Essays on Mind and Psychology, Chapter 6


"Dennett (Daniel) - Artificial Intelligence as Philosophy and as Psychology"

Source: Dennett - Brainstorms - Philosophical Essays on Mind and Psychology, Chapter 7

COMMENT: Part II. The Nature of Theory in Psychology.

"Dennett (Daniel) - Are Dreams Experiences?"

Source: Dennett - Brainstorms - Philosophical Essays on Mind and Psychology, Chapter 8

Philosophers Index Abstract
    The "received view" that dreams are experiences is challenged by contrasting it with a "cassette theory" according to which dream-recollections are produced by entirely unconscious processes. The point of this exercise in speculation is to establish that the received view is an empirical theory whose truth is not to be settled by everyday facts about dreamers, and to support and illustrate some claims about memory and experience in general.

COMMENT: Part III. Objects of Consciousness and the Nature of Experience.

"Dennett (Daniel) - Towards a Cognitive Theory of Consciousness"

Source: Dennett - Brainstorms - Philosophical Essays on Mind and Psychology, Chapter 9

COMMENT: Part III. Objects of Consciousness and the Nature of Experience.

"Dennett (Daniel) - Two Approaches to Mental Images"

Source: Dennett - Brainstorms - Philosophical Essays on Mind and Psychology, Chapter 10

COMMENT: Part III. Objects of Consciousness and the Nature of Experience.

"Dennett (Daniel) - Why You Can't Make a Computer that Feels Pain"

Source: Dennett - Brainstorms - Philosophical Essays on Mind and Psychology, Chapter 11

Author’s Introduction
  1. It has seemed important to many people to claim that computers cannot in principle duplicate various human feats, activities, happenings. Such aprioristic claims, we have learned, have an embarrassing history of subsequent falsification. Contrary to recently held opinion, for instance, computers can play superb checkers and good chess, can produce novel and unexpected proofs of nontrivial theorems, can conduct sophisticated conversations in ordinary if tightly circumscribed English.
  2. The materialist or computerphile who grounds an uncomplicated optimism in this ungraceful retreat of the skeptics, however, is in danger of installing conceptual confusion in the worst place, in the foundations of his own ascendant view of the mind. The triumphs of Artificial Intelligence have been balanced by failures and false starts.
  3. Some have asked if there is a pattern to be discerned here. Keith Gunderson has pointed out that the successes have been with task-oriented, sapient features of mentality, the failures and false starts with sentient features of mentality, and has developed a distinction between program-receptive and program resistant features of mentality.
  4. Gunderson's point is not what some have hoped. Some have hoped he had found a fall-back position for them: viz., maybe machines can think but they can't feel. His point is rather that the task of getting a machine to feel is a very different task from getting it to think; in particular it is not a task that invites solution simply by sophisticated innovations in programming, but rather, if at all, by devising new sorts of hardware.
  5. This goes some way to explaining the recalcitrance of mental features like pain to computer simulation, but not far enough. Since most of the discredited aprioristic thinking about the limitations of computers can be seen in retrospect to have stumbled over details, I propose to conduct a more detailed than usual philosophic thought experiment1. Let us imagine setting out to prove the skeptic wrong about pain by actually writing a pain program, or designing a pain-feeling robot. I think the complications encountered will prove instructive.

COMMENT: Part III. Objects of Consciousness and the Nature of Experience.

"Dennett (Daniel) - Mechanism and Responsibility"

Source: Dennett - Brainstorms - Philosophical Essays on Mind and Psychology, Chapter 12


"Dennett (Daniel) - The Abilities of Men and Machines"

Source: Dennett - Brainstorms - Philosophical Essays on Mind and Psychology, Chapter 13

COMMENT: Part IV. Free Will and Personhood.

"Dennett (Daniel) - Conditions of Personhood"

Source: Dennett - Brainstorms - Philosophical Essays on Mind and Psychology, Chapter 14
Write-up Note1 (Full Text reproduced below).

Dennett suggests that the concepts of “person” and “human being” are not necessarily co-extensive. He also distinguishes the two intertwined notions of personhood – moral and metaphysical. He defends the following 6 “themes” as necessary conditions of personhood:-
  1. Persons are rational beings.
  2. Persons are beings to which states of consciousness are attributed, or to which psychological or mental or intentional predicates are ascribed.
  3. Whether something counts as a person depends in some way on an attitude taken toward it, a stance adopted with respect to it.
  4. The object toward which this personal stance is taken must be capable of reciprocating in some way.
  5. Persons must be capable of verbal communication.
  6. Persons are distinguishable from other entities by being conscious in some special way: there is a way in which we are conscious in which no other species is conscious. Sometimes this is identified as self-consciousness of one sort or another.
Dennett addresses three issues to do with these 6 themes:
  1. How (on his interpretation) are these 6 themes dependent on one another?
  2. Why are they necessary conditions of moral personhood?
  3. Why is it so hard to say whether they are jointly sufficient conditions for moral personhood?
For further discussion, Click here for Note, together with a supervision - Click here for Note - discussion on this paper.


Write-up2 (as at 18/12/2010 19:58:05): Daniel Dennett – Conditions of Personhood

Dennett suggests that the concepts of “person” and “human being” are not necessarily co-extensive. He also distinguishes the two intertwined notions of personhood – moral and metaphysical. He defends the following 6 “themes” as necessary conditions of personhood:
  1. Persons are rational beings.
  2. Persons are beings to which states of consciousness are attributed, or to which psychological or mental or intentional predicates are ascribed.
  3. Whether something counts as a person depends in some way on an attitude taken toward it, a stance adopted with respect to it.
  4. The object toward which this personal stance is taken must be capable of reciprocating in some way.
  5. Persons must be capable of verbal communication.
  6. Persons are distinguishable from other entities by being conscious in some special way: there is a way in which we are conscious in which no other species is conscious. Sometimes this is identified as self-consciousness of one sort or another.
Dennett addresses 3 issues to do with these 6 themes:
  1. How (on his interpretation) are these 6 themes dependent on one another?
  2. Why are they necessary conditions of moral personhood?
  3. Why is it so hard to say whether they are jointly sufficient conditions for moral personhood?
In this essay, rather than address Dennett’s 3 issues directly, I wish to address the following 6 questions:
  1. Is Dennett right to separate the concepts of “person” and “human being”?
  2. Is Dennett right to distinguish moral from metaphysical personhood?
  3. Has Dennett the right set of themes?
  4. Has Dennett found the right interdependencies and priorities amongst his themes.
  5. What are Dennett’s reasons for predicating these conditions of personhood?
  6. Finally, is Dennett guided by a natural kind concept, by social convention or by other factors?
I have to admit that this is a first draft and something of a rushed job. My aim at this stage is to generate ideas quickly rather than ensure the argument is fully rigorous. I’m afraid I’ve used Dennett’s paper more as a jumping off point, and have not considered his actual arguments as much as I should. I’ve included hyperlinks to topics I’ve written before, as a way of airing them and avoiding needless repetition, though the primary aim of this essay is to provide some continuous text for discussion, rather than exemplifying the approach of my research proposal (from where these notes come) which is almost all footnotes.

My aim in reviewing this paper is to get some sort of handle on what a person might be. The aim of my thesis will be to demonstrate that human persons are phase sortals of human animals, and that consequently (given the falsehood of mind/body dualism) that such hoped-for events such as resurrection are metaphysically impossible. I’m not arguing for any of this here, just motivating the consideration of this topic.

Page references are to the 1997 Penguin edition of Brainstorms (Chapter 14).

Persons and Human Beings

Dennett claims that while any reader of his essay has to be person, the reader need not be a human being. The reader could be an alien, for instance. However, as far as I can see, to read Dennett’s essay with reward, only rationality, language use, phenomenal consciousness and intentional states are strictly required. The moral themes seem irrelevant, as does the consciousness of self (though a reader without this concept might find the essay initially rather dull, though maybe enlightening).

So, the reader might not be a moral person by Dennett’s lights. Dennett is probably right, though, that infants, “mental defectives” (how sensibilities have moved on since 1978, or whenever this Chapter was drafted) and the appropriately insane, would not get much out of his offering. However, the contemporary candidates of choice for human non-personhood tend these days to be moved closer to the termini of life, being (early) fetuses and those in a persistent vegetative state (though maybe the question is different – in Olson the question is whether “we” have psychological states essentially, and the claim is that “we” do not since “we” existed as fetuses, and may (for all we now know) persist into a PVS).

However, this leads on to our next question.

Moral and Metaphysical Persons

Dennett’s distinction between moral and metaphysical persons seems to change the topic of the conversation to one I’m less interested in. While it’s not always 100% clear (at least to me), the bulk of his essay is addressed to the topic of moral persons rather than metaphysical persons. Because he agrees that Frankfurt’s ideas about wantons3 are fruitful, Dennett excludes many human beings from the category “person” that I would prefer to include.

However, the motivation behind this distinction is whether or not the term “person” is a “free-floating honorific”, like “chic” (p. 268). He distinguishes the metaphysical notion of person (“an intelligent, conscious, feeling agent”) from that of the moral notion (one “who is accountable, who has both rights and responsibilities”). He wants to know whether being a metaphysical person is a prerequisite for being a moral person, something a metaphysical person can “grow into”, or whether metaphysical persons must be moral persons. He points out that we still in general react to the clinically insane (unless they are very far gone) as though they are metaphysical persons, even though they may not be treated as moral persons. Hence, the two terms are distinct, though being a metaphysical person does seem to be a necessary condition for being a moral person (with the exception of compound persons such as companies).

The Right Set of Themes?

I can’t really do better in defining what I think persons are than does Locke4. An entity for which persistence matters; a thinking thing that can consider itself as itself; that is phenomenally conscious, and has a consciousness of self. This is approximately Dennett’s metaphysical person, though we mustn’t forget that Locke famously considered personhood a forensic5 concept.

Now on to Dennett’s specific themes:
  1. Rationality: I’m not sure how far rationality should be pressed, despite Dennett considering it “the most obvious” (p. 269). I don’t think it’s essential for a metaphysical person. However, the assumption of rationality is essential in all our dealings with other sentient entities (Dennett’s intentional stance won’t work otherwise), so it is probably essential for moral personhood. Even then, “predictability” might be more relevant than rationality.
  2. Intentional Predication: I’m happy with this, as it is a prerequisite for all mindedness (though not a sufficient condition). I’m happy that persons are minded beings, even if human beings aren’t always.
  3. The object of a stance: this seems to suggest that who is a person is in some sense “up to us”. Indeed Dennett says (p. 270) that it’s not just a stance taken in response to a metaphysical person, but is as least partly constitutive of a moral person (I paraphrase). This is definitely a predicate for moral persons only. While it might as a matter of fact be the case that certain metaphysical persons are socially ostracised so as to be treated as moral non-persons, this doesn’t make them non-persons in either the metaphysical sense or the moral sense (for a moral realist).
  4. Reciprocation: Again, this is necessary only for moral persons. A sociopath or convinced solipsist is still a metaphysical person.
  5. Verbal Communication: Presumably Dennett is not disbarring deaf mutes from personhood, nor Stephen Hawking were someone to tread on his laptop. Even so, the possession of a language of thought (along Fodor’s lines) is probably a prerequisite for rationality, but this doesn’t address Dennett’s themes of communication and reciprocal attitudes. Metaphysical persons incapable of communication might not be moral persons. I expect there are large questions about how a sense of self might arise without language. One would need to consider feral children. This might connect to a question I had in connection with the Language Acquisition Thesis (the claim that “learning a language is instrumental in the development of conceptual faculties in a human subject”). See the following link6.
  6. Self-Consciousness: I think this is central to either metaphysical or moral personhood. See below under “Natural Kinds”. Dennett takes this form of consciousness (like language) to be the unique preserve of the human species, though I gather that both claims are not controversial (with the teaching of American Sign Language to bonobos, and the question whether passing the mirror test demonstrates a sense of self).

I have a question whether the properties Dennett requires of persons are their present properties or capacities, or whether entities that will, in the normal course of events, develop into persons, or which have in the past if not in the present possessed such capacities, count as persons. Is the property of being a person inalienable? Clearly capacities are more important than their present exercise (after all, we are not always rational or self-conscious, or even conscious at all; personhood is a state, not an activity).

This relates to whether human persons are phase sortals7,8 of human beings, or whether they are human beings, period. It looks as though Dennett would deny the latter suggestion, given his insistence on certain properties that not all human beings share.

Interdependencies and Priorities amongst the Themes

This will mostly have to wait for future elaboration. Dennett (p. 271) claims that the 6 themes are given in the order of their dependence with the proviso that the first 3 are mutually interdependent. Enough to note here that an item I consider essential to metaphysical personhood, namely self-consciousness, appears at the bottom of Dennett’s list and so is presumably taken to be reliant on predicates only necessary for moral personhood. I would deny this connection.

Why These Themes?

This will also mostly have to be left until a later date.

As I note above, Dennett considers the order of the themes important, and considers that the earlier ones as prerequisites for the later ones. In particular, because we can adopt the intentional stance towards beings such as plants that have no mental states (“it grows that way because it wants to get to the light”), we need to move on to those that have real beliefs and desires. He is worried (p. 273) that we might get the themes in the wrong order by the premature invocation of the conscious knowledge or verbal expressibility of our beliefs to ensure their genuineness, but in any case these conditions are too strong as we have many beliefs that we’re either unaware of or cannot express. This is why he brings in his fourth theme, that of reciprocity. While we can adopt the intentional stance towards plants, they cannot return the favour. He also assumes this reciprocity fails for all non-humans, but I suspect he’s wrong. Maybe this is a step in the right direction, but adopting Frankfurt’s approach (however useful the concept of a wanton is) seems to me to be a step too far in this context (and even in Frankfurt’s context).

What Sort of a Concept is “Person”

At the beginning of his essay, Dennett asks whether the concept of a person is incoherent or obsolete. His answer is that it isn’t, because we cannot cease to regard others, and in particular ourselves as persons without contradiction (and refers us to "Dennett (Daniel) - Mechanism and Responsibility"). I’ve not pursued this question, but suspect that the fact that the question can be asked at all indicates that the concept of person isn’t a natural kind concept, at least not as the term “moral person” is defined by Dennett. There seem to be too many attitudinal issues and those that make certain sorts of societies cohere (even though these may arguably be the best sort).

I don’t seem to have written anything sensible on natural kind9 concepts. Maybe this is a next step. My intuition is that persons, whether metaphysical or moral, aren’t natural kind concepts, and that for human persons the appropriate natural kind concept is “human animal” (or maybe “human being”).

A critical question, however, is whether the emergence of self-consciousness signals the arrival of a new natural kind (as Lynne Rudder Baker alleges, taking “self-consciousness” to be the same as her “first-person perspective”).

In-Page Footnotes ("Dennett (Daniel) - Conditions of Personhood")

Footnote 2:
  • This is the write-up as it was when this Abstract was last output, with text as at the timestamp indicated (18/12/2010 19:58:05).
  • Link to Latest Write-Up Note.

"Dennett (Daniel) - On Giving Libertarians What They Say They Want"

Source: Dennett - Brainstorms - Philosophical Essays on Mind and Psychology, Chapter 15

COMMENT: Part IV. Free Will and Personhood.

"Dennett (Daniel) - How to Change Your Mind"

Source: Dennett - Brainstorms - Philosophical Essays on Mind and Psychology, Chapter 16

COMMENT: Part IV. Free Will and Personhood.

"Dennett (Daniel) - Where Am I?"

Source: Dennett - Brainstorms - Philosophical Essays on Mind and Psychology, Chapter 17

  1. This paper is an entertaining amalgam of TEs1 that Dennett admits are indebted to essays in "Rorty (Amélie Oksenberg), Ed. - The Identities of Persons", in particular to:-
    1. "Lewis (David) - Survival and Identity",
    2. "Parfit (Derek) - Lewis, Perry, and What Matters",
    3. "Perry (John) - The Importance of Being Identical", and
    4. "Shoemaker (Sydney) - Embodiment and Behavior".
  2. The conceit of the paper is that Dennett is giving a talk describing various vicissitudes beloved of philosophers of personal identity that he has survived (maybe) and one of which occurs during the speech itself.
  3. For dubious reasons that need not detain us, Dennett has had his brain2 removed for safe-keeping and placed in a vat3, from where it controls his body by remote control. Pairs of radio transceivers attached to “nerve stumps in the empty cranium” and “the brain” connect up each “input and output pathway” so that – effectively – the nerves are stretched4.
  4. After the operation, Dennett initially feels a little “light headed5”, but is otherwise fine and is taken to see his brain floating in its vat of nutrients, where it is almost covered6 with “printed circuit chips, plastic tubules, electrodes, etc.”.
  5. To prove that the BIV is Dennett’s, he’s invited to flip7 a switch, after which he immediately8 “slumps groggy and nauseated”, and upon which an assistant flips the switch back, allowing Dennett to “recover his equilibrium and composure”.
  6. Dennett now tries to consider where he is (the title of the paper). Despite believing – as a “firm physicalist” – that “the tokening of his thoughts occurred somewhere in his brain”, he couldn’t convince himself that he – Dennett – was in the vat. Rather9, he was outside where he stood.
  7. Also, while he has no trouble with imagining various locations for “there”, he does not have the same flexibility for “here”.
  8. To try to make things clearer, he adopts the “standard philosophical ploy” and names things: his brain “Yorick”, (the rest of) his body “Hamlet”, while he himself remains “Dennett”. So, where is he, and where is the thought “where am I?” tokened – in his brain (in the vat), or between his ears (“where it seems10 to be tokened”)? Dennett claims that he has no trouble with the temporal coordinates of thought-tokens, only their spatial coordinates.
  9. So where is he (Dennett)? He thinks of three possibilities:-
    1. Where Hamlet goes: Dennett rules this out immediately because of the Brain Transplant11 intuition: we go with our brain because it’s responsible for our psychology. A brain transplant12 is really13 a body transplant14.
    2. Where Yorick goes: Dennett says this isn’t appealing either – how can he be in a vat when he seems to be walking around? Dennett borrows from Locke the idea that personal identity is a forensic15 matter, and considers what US State he’d be tried in if Hamlet committed a crime16, and considers whether Hamlet or Yorick would “do the time17”, and where.
    3. Wherever Dennett thinks he is: the person is where his point of view (POV) says he is. Dennett rather confusingly18 spells this out by saying that “the location of the POV (which is determined internally by the content of the POV19) is the location of the person”. Dennett points out that this would make one’s location infallibly known, yet one has sometimes got lost. Worse, while lost in the woods, one could – at least in normal circumstances – confidently assert that one was in one’s body, but in these unusual circumstances Dennett wasn’t so sure.
  10. Dennett continues his discussion of PoVs:
    1. PoV has something to do with location, but the content of one’s PoV isn’t the same as (or even determined by) the content of one’s beliefs or thoughts20.
    2. Cinerama viewers suffer illusory shifts in points of view.
    3. Other PoV-shifts are less illusory: for instance the use of feedback-controlled mechanical arms in the nuclear industry; they can shift their PoV into the isolation chamber, but are not fooled into false beliefs, and are not transferring themselves there.
    4. There’s a final paragraph in this section where Dennett soliloquises on practice and training one’s PoV:-
      1. If I were really in the vat, I could train myself habitually to adopt that PoV – images of me floating there and beaming volitions to my body elsewhere.
      2. He suggests the ease of this task is independent of the truth of the brain’s location, and might have become second nature had he practiced before the operation – indeed the reader could try it out21.
  11. Dennet now helpfully explores the consequences of the TE:
    1. He repeats the suggestion about initial dizziness – again without explanation. He says this is so only “initially”, and that he soon habituates himself to his new situation, which is “well-nigh indistinguishable” from his former circumstances. However, …
    2. Due to the finite speed of light, he suffers minor coordination difficulties on account of feedback loops. He gives the example of being rendered speechless by hearing your own voice repeated, as in an echo22. He’s unable to track a moving object – such as a ball – when brain and body are more than a few miles apart.
    3. An advantage – he says – is that he can drink any amount of alcohol, which now only warms his gullet, though is still corrodes his liver.
    4. However, while he can take aspirin orally for a sprain, persistent pain requires codeine to be administered to his brain in vitro23.
  12. Dennett now sets off on his mission, leaving his brain hundreds of miles away.
    1. On the way, Dennett decides that he has become a “scattered24” person, rather than that – as he had thought unreflectively – he’d just left his brain behind.
    2. He gives a very poor analogy25: his being in two places at the same time – both in the vat and outside it – is just like someone standing astride a boundary between two states.
    3. Dennett says that while this now seemed obviously true, the philosophical question to which it was supposedly the right answer now seemed less important, as occasionally happens in philosophy.
    4. Yet, the answer was not entirely satisfying. His question was neither “where are my parts” nor “what is my current PoV”; for, there was a sense in which he believed that he and not merely most of him had gone off on his mission.
  13. When he gets down to work on his mission, all’s well until his transceivers start to fail, and he loses his senses (ie. in turn he goes deaf, dumb, blind and paralysed).
    1. He is now to consider himself disembodied in his vat.
    2. Dennett claims that his body is still alive – in that the heart and lungs are still working – but that it’s otherwise “as dead as the body of any heart26 transplant27 donor”.
    3. The shift in perspective now seemed entirely natural. He could still imagine28 himself back in his body, but it was an effort now he’d lost all contact with it.
  14. Dennett now has what I presume is a little joke. His alter ego pretends to have a revelation to the effect that “he has discovered the immateriality of the soul based on physicalist principles and premises”.
    1. The “proof” is that when the last transceiver failed, “he” – or at least his massless soul or mind – travelled hundreds of miles at the speed of light to take up residence in his vat, with no increase in mass.
    2. His PoV had lagged behind somewhat, but this has already been shown to be indirectly correlated with location.
    3. He thinks a physicalist philosopher could only disagree with his “revelation” by banishing all talk of persons29, but personhood is too embedded in everyone’s worldview to be jettisoned, any more than adopting an anti-Cartesian30 “non sum”.
  15. He says this “revelation” tided him over as panic – and even nausea31 – swept over him when he realised his “condition”.
    1. He’s then put into a “dreamless sleep”32 to be awakened by music fed directly into his auditory nerve.
    2. He is assured that efforts are being made to re-embody him, and a year later he does indeed find himself “housed” in a different body.
    3. He notes that philosophers33 speculate that the acquisition of a new body leaves one’s person intact.
    4. He admits there are physical changes to get used to, but any personality changes are no worse than those encountered by those undergoing plastic surgery or sex change, when no-one doubts the persistence of the person.
  16. Dennett names his new body “Fortinbras” and goes34 to visit Yorick, his brain in its vat.
    1. Once there, he flips the transceiver switch but – rather than “slumping” as previously – nothing happens; he notices no difference, nor when the switch is flipped back.
    2. The “explanation” is that – even before his first operation35 – a “computer duplicate” brain had been created.
    3. This “brain” – named “Hubert”, and running on a “giant computer” – reproduced both the information processing structure and computational speed of his brain (Yorick) and had been running in parallel even before his “mission”.
    4. So, the story goes that sensory input from Hamlet – his former body – was – on receipt by the transceivers – sent both to Yorick (his brain) and to the “computer’s array of inputs”. Also, while output from Yorick was sent to Hamlet, it was also stored and compared with that from Hubert.
    5. Over time, the outputs were identical and synchronous, which provided empirical evidence – if not proof – that Yorick’s functional structure had been successfully copied36.
    6. It is now revealed that Hamlet had been destroyed in the course of the failed mission, but Hubert has been kept37 synchronised with Yorick.
  17. Now there is a second switch that is presently set to have Hubert control Fortinbras.
    1. Dennett is asked to flip the switch so that control is passed back to Yorick – he feels nothing38 – and then to prove that Yorick really is now in control, is asked to flip the transceiver switch. Fortinbras immediately starts to slump, but recovers when it is flipped back.
    2. Dennett is left to fiddle with the control switch, and never notices any difference, even if it’s done in mid-sentence39.
    3. So, it is suggested – Dennett now has a “spare40 brain” should anything happen to Yorick.
    4. It’s noticed (in passing41) that wear and tear to Fortinbras has no debilitating effect on either brain.
  18. The TE moves on to the further thought about what would42 happen if one of Hubert and Yorick were detached from Fortinbras and hitched up to another body – Rosencrantz, say.
    1. Then, there would be two persons each claiming to be Dennett – but which43 one would be?
    2. The usual arguments are rehearsed:
      1. The Yorick-brained one has causal priority and was originally intimately connected to Hamlet. Dennett (purports to) downplay this as two legalistic for metaphysical purposes.
      2. For, imagine that Hubert had been driving Fortinbras for years, with Yorick as a “spare44”. He alleges that Hubert-Fortinbras would then have “squatter’s rights” to be legally accounted the true Dennett.
    3. “Dennett” claims that his intuition is that he would survive if either45 combination survived, but would “have mixed emotions about whether he should want both to survive”.
  19. We now have the usual discussion of the problems of fission46.
    1. Two Dennetts would be abhorrent (to Dennett) firstly for social reasons (shared wife, salary, …)
    2. Additionally, Dennett doesn’t like the idea of someone else knowing so much about him.
    3. However, those in the lab try to persuade him that there’s a plus side – he’d be able to do twice as much.
    4. Dennett isn’t sure he’d take up the offer47, and isn’t sure it’s being offered to him48 in the first place.
  20. Retreating from the fission question, Dennett is more worried by the thought of one of the brains becoming detached49 from Fortinbras.
    1. So, he asks for reassurance that no-one can fiddle with either the transceiver or master switch.
    2. He says this request is both50 driven by self-interest and altruism.
    3. So, we are led to believe, Dennett has the master switch about his person (the local ones – controlling the environment for Yorick (and, presumably, access to the transceiver switch) and the power supply for Hubert - are “locked down”) and he checks all is well with both brains occasionally by flipping the master switch in the presence of someone who will flip it back should he flip to Yorick, and Yorick’s transceiver be set to “off”.
    4. For, in the latter case, while he’d have sensory input from Fortinbras, he’d not be able to control51 his body.
    5. It is said that the master switch is unmarked, so Dennett never knows whether Yorick or Hubert is in charge of Fortinbras.
    6. If this means that Dennett52 doesn’t know who he is, then
      1. This doesn’t make much of a dent in Dennett’s sense of who he is – his “essential Dennettness53”, and
      2. This just shows that the question is of less interest than philosophers have claimed.
  21. So, he gives the master switch another flip and there’s an explosion of complaint from Fortinbras54!
    1. Two weeks ago, the two brains drifted slightly apart, and then the differences snowballed because the brains were then in a different receptive state for identical sets of input from the single body (Fortinbras).
    2. Hence, the illusion that Yorick (or Hubert) was in control of “his” body was dissipated. It was like being carried around in a cage - like being possessed – hearing himself say things he didn’t mean to say, and seeing his hands do things he’d not intended.
    3. “His brother” would scratch “our itches” – but not in the way Dennett would have, and would keep him awake
      • On reflection, I think this is a correct scenario.
      • While both Yorick and Hubert receive the same itches from Fortinbras – so neither should be surprised (or wakened) by tossing and turning on that account,
      • However, tossing and turning may be instigated by worries in “the other’s” mind, and if these worries are not shared, the tossing and turning would be inappropriate and awakening.
      with his tossing and turning. He’d been “in purgatory” – on the verge of a nervous breakdown – carried around helplessly by the other’s frantic round of activities and sustained only by the thought that eventually the other would flip the switch, and it’d be his turn for torment.
    4. So, it’s now the other’s turn – but at least he knows that “Dennett” knows he’s “in there” disconnected – which was not the case for “Dennett” himself.
  22. The current problem can only be resolved by getting another body for “the other”:-
    1. Otherwise, the situation is like an expectant mother – “eating55 – or at any rate tasting, smelling, seeing – for two”.
    2. Who keeps the current body (Fortinbras) is to be decided56 by the flip of a coin, and the other can have a choice of bodies.
  23. “Dennett” then sits down after making the final remark that – while the talk isn’t exactly what he’d have said – it’s entirely true.


In-Page Footnotes ("Dennett (Daniel) - Where Am I?")

Footnote 2:
  • For brains, Click here for Note.
  • It is a constant complaint that TEs in this and other areas of philosophy are underspecified, so it’s not clear what conclusions to draw from them.
  • In this case it is not specified quite how much of Dennett’s brain is placed in the vat – in particular whether it includes the brain stem.
  • The text says it is to be “completely removed”, but a later passage alludes to Dennett’s body continuing to function in its absence, and also in the absence of communication with it.
  • I don’t know enough about neuroscience to know whether heart and lungs can continue to function in the absence of control from the brain stem (but I seem to remember – and Wikipedia confirms (Wikipedia: Brainstem) – that in humans the brain stem “plays an important role in the regulation of cardiac and respiratory function”
  • Decapitations may not be a close-enough parallel. Chickens appear to be able to run around “like headless chickens”. Human beings have much larger brains requiring a much greater blood supply, so this will have a greater impact on the headless human corpse than would be the case for a chicken.
  • Anyway, we can assume that Dennett intends that the brain stem does get transplanted to the vat. Any quibbles about the supposedly continued cardiac and respiratory function in the absence of brain stem control can be put down to a slip that is irrelevant to the TE as a whole.
Footnote 4:
  • As far as transfer of impulses is concerned, practical difficulties aside, I see nothing immediately wrong with this as a TE.
  • There are, however, various concomitant problems that will be demonstrated in due course.
Footnote 5:
  • Dennett doesn’t say why he should feel light-headed.
  • The normal cause of light-headedness is low blood-pressure, which is a proxy for reduced blood-flow and oxygen levels.
  • I can imagine it would be difficult to maintain the very high blood pressure usually enjoyed by brains in a free-floating brain not protected by the skull – thought a prosthetic plastic “see through” skull might do the trick if the arterial connectors can stand the pressure, as no doubt we can assume they could.
  • The “light headedness” isn’t described as an initial set-up (connection) problem but as some sort of consciousness acclimatisation problem. If related to blood pressure, why would it not persist?
  • The whole idea of a brain “floating in a vat of nutrients” is rather ludicrous. Presumably the brain would receive energy as normal from oxygenated blood. Maybe the whole “light-headedness” conceit is a nod to this vagueness in the description of the TE.
Footnote 6:
  • Naturally, this is all a bit vague.
  • I can’t see why the cortex should be covered with anything, as the bulk of the pathways would be via the spinal cord, thought there would need to be “extras” for links to the eyes, ears and nose/tongue.
  • I’m not sure where all these pathways go, but I dare say we can let the lack of detail pass. It is important to think them through to some degree to avoid the charge of under-specification.
Footnote 7:
  • Actually, what it says is “hit the output transmitter switch”, so it’s only instructions from the brain to the body that are cut off.
  • This is important, for continual input of sense data is important for later (Hubert, the computer-brain) even when output is switched off.
Footnote 8:
  • It is important to pick nits in TEs. So,
  • Just why does Dennett react in this way to the disconnection of his brain from his body?
  • Why does he feel “groggy and nauseated”? These symptoms sound like those associated with lack of oxygen rather than loss of information and control.
  • That said, the body stops receiving instructions from the brain but still feeds back sensory / somatic data to the brain, so who knows how the situation would be interpreted? Dennett’s suggestion may be OK.
  • Why does he slump? This is easier to understand, depending on how much control is due to the spinal cord. Chickens run around with their heads cut off, it is said.
  • I intend to look into these things in due course, after a revision of neurophysiology.
Footnote 9:
  • What do I think is the answer to the essay’s central question? Where is Dennett (in this TE)?
  • I think it depends on what we are talking about.
  • As a person to be interacted with socially – or even a human animal interacting with the world – Dennett is outside the vat.
  • However, metaphysically-speaking, he is a scattered object (like the solar system).
  • Later on – where Dennett’s brain is paralleled (or even supplanted) by a computer simulation (as I would say) – would it still be right to say he’s scattered, and where is the brain-alike? Is it the whole computer on which the simulation runs? Or is Dennett just his body then, with an alien puppet-master?
Footnote 10: Surely, thoughts don’t seem to be tokened anywhere? It’s only theory (science) that tells us that they are tokened in our brains, but they don’t “feel” as though they are there, do they?

Footnote 13: Of course, animalists disagree with this intuition, though it is hard to explain away. It’s hard to argue that the brain is “just another organ”, though they have a go.

Footnote 16:
  • I wasn’t impressed by this.
  • Even if Yorick was in another State to where the crime was committed, the crime would be committed in the State it was, by Hamlet – and he (not Yorick) would be tried there.
  • It all depends how the situation is described – and giving parts of a human being names only confuses matters, as it implies that they are separate individuals.
  • It is wrong to describe the situation as of a “master mind” and “an accomplice”.
Footnote 17:
  • Again, this is all getting rather silly.
  • Yorick and Hamlet aren’t two individuals that can be treated separately.
  • Yorick is already as incarcerated as anyone can be, but the well-being of Yorick depends on that of Hamlet.
  • … and the vat of nutrients, of course, but this is true of any brain – it’s just that in this case, the life-support has been sub-contracted.
Footnote 18:
  • Do POVs have locations? Aren’t they brain states? A POV will say where the person thinks he is, which seems to be what Denett is after.
  • Alternatively, a POV is a “viewpoint”, which is just a directed gaze from a specific location in space.
Footnote 19: A POV seems to be equivalent to Baker’s FPP, but may be much narrower, being restricted to geographical perspective.

Footnote 20: Dennett says this is “obvious”, but I’m not even sure what he means, or how it follows!

Footnote 21: Dennett fills out this thought, but I didn’t really get what he was after, and the thought is left hanging as we move on ….

Footnote 22: I’ve had this on the phone, and I know what he means.

Footnote 23: Several points here:-
  • This shows the importance of local chemical activity within the brain. Not all sensation is covered by information transfer between the body and the brain: some is dependent on chemical transfer within the blood stream. However, these chemicals bind to receptors within the brain, which inhibit or enhance neural firing, so all mental life may ultimately boil down to information transfer, though several in the “consciousness” debate (eg. Roger Penrose and Stuart Hammeroff) have it that qualia depend on quantum events in microtubules within the brain structure.
  • The distinction between the action of aspirin and codeine is interesting: presumably aspirin acts within the body and inhibits pain-messages being sent to the brain, while codeine acts on the receptors within the brain where these messages are received.
Footnote 25:
  • Interstate boundaries are not real barriers to somatic integrity in the way that hundred-mile gaps are.
  • So, this case is entirely different – such a person is not scattered at all, and is only conventionally in two places at once.
Footnote 26:
  • This is a strange way of putting it, as this body still has a heart.
  • If the body is still supposed to be functioning, then we might suppose that the brain stem remains with the body, and only the cerebrums are in the vat; but I’ve earlier ruled out this idea.
  • I’m not sure either of these points are important, though the latter is an important detail in the description of the TE; for instance if it required the brain stem to be in two places at once it might signal a contradiction.
  • But it’s not essential to the TE that Dennett’s detached body should continue to live, I don’t think.
Footnote 28:
  • It’s difficult to imagine quite what it would be like to be in those circumstances. All proprioceptive sense would be lost, and there’d be no sensation from the body at all, worse than any case of quadriplegia or MS.
  • How do/did people such as Stephen Hawking or Tony Judt describe their predicaments? I understand they have “just” lost motor control, and still retain sensation – indeed, I seem to remember reading something by Tony Judt to the effect that he used to get cramps in the night when he wasn’t turned, and that this caused him agonies.
  • We’d need accounts from those with “locked in syndrome” (see "Bauby (Jean-Dominique) - The Diving-Bell and the Butterfly", but again Bauby describes his body as a source of pain) or maybe those investigated by Oliver Sacks in Awakenings - Wikipedia: Sacks - Awakenings.
  • Interestingly, Bauby was in the state he was because of damage to his brain stem. However, he’s not on a heart/lung machine, so sufficient of his brain stem must have remained intact to continue to regulate these vital organs.
Footnote 30: Dennett refers us – without explanation – to "Hintikka (Jaakko) - Cogito, Ergo Sum: Inference or Performance?".

Footnote 31:
  • I’m not convinced that a cerebrum in a vat could feel these emotions, which I suspect are triggered by adrenaline (see Wikipedia: Epinephrine), naturally synthesised in the adrenal glands above the kidneys (see Wikipedia: Adrenal gland), which is a chemical carried in the bloodstream.
  • Dennett admits that adrenalin would be absent, but implies that this – along with a sinking feeling in the bowels – would be the first of many “phantom limb” analogues.
  • I’m not sure whether this would be the case – phantom limb pain is – presumably – generated by firings in the neural pathways commencing at the point where the limb was amputated. So, the analogue here would be the place where the local transducers are attached to the brain. But if they produce “phantom body” feelings when their transmissions cease, wouldn’t they do likewise prior thereto? Are the cases properly analogous?
Footnote 33: Well, many do, but animalists (slightly implausible) deny this, saying that the new body receives a new brain.

Footnote 34: This may be a tendentious description. Fortinbras is not the continuer of Hamlet in any sense.

Footnote 35: Ie. The one that removed his brain and set up the transceiver system.

Footnote 36:
  • Because we’re dealing with what are most likely non-linear systems, it’s very unlikely that the creation of a functional equivalent would be a practical possibility without continual intervention – occasionalism, in other words (see "Lee (Sukjae) - Occasionalism"). Leibnizian parallelism (pre-established harmony, "Rodriguez-Pereyra (Gonzalo) - Leibniz on mind-body causation and Pre-Established Harmony") has always been incredible. Not that these positions are talking about the same thing, but near enough.
  • But, even if it were, what have we done? Is a “functional duplicate” a duplicate “full stop”?
  • I don’t enthuse over functionalism, but am happy to concede (for the sake of the argument, the above worries aside) that – as is claimed – “Yorick’s functional structure had been successfully copied”.
  • However, this doesn’t mean that “Dennett has spare brain” (as will be surmised later), nor that the “computer brain” is anything other than a simulation without any phenomenal consciousness.
Footnote 37:
  • Initially by just “running” (like Yorick) in the absence of input,
  • But latterly by receiving all and only the same inputs from Fortinbras that Yorick has.
Footnote 38:
  • Is this credible?
  • The way the situation is best understood – it seems to me – is that Dennett’s FPP resides – and always will reside – in Yorick. Hubert is nothing but a simulator.
  • So, when control is passed to Hubert, which stays in parallel with Yorick, then Yorick still feels in control.
  • To remind ourselves – the reason the parallelism is maintained is that for the sake of this TE it is assumed that functionally equivalent processors will remain synchronised given the same inputs.
  • So, when the “control” switch is flipped, Yorick indeed wouldn’t notice anything.
  • However, if Yorick were extinguished, Dennett’s FPP wouldn’t “pop” over to Hubert, even though – if control were passed, Fortinbras would carry on regardless and the Fortinbras / Hubert combination would act like Dennett.
Footnote 39:
  • Because of non-linearity, we either have exact synchronisation and parallelism or none at all (as we will see at the end).
  • So, we are to assume exactness, and the “mid-sentence” claim is fine.
Footnote 40:
  • I strongly disagree here.
  • The computer brain (Hubert) is at best a copy, and at worst a simulation, of the real brain (Yorick).
  • Yorick’s FPP is never going to hop over to Hubert.
Footnote 41:
  • Is there any point to this remark?
  • As Fortinbras starts to wear out, this will have an impact on the control functions of both Yorick and Hubert, but there would be possibility of damaging either by (say) blood poisoning, anoxia or the like.
Footnote 42:
  • So, we have a TE within a TE!
  • It’s important to bear this in mind as this TE never “happens” to the Dennett of the article.
Footnote 43:
  • Well, I would say at most one – namely the one involving Yorick.
  • But a bit of explanation has gone missing – Yorick and Hubert were kept synchronised. How was this done?
    • It looks as though it was supposed to happen because the two brains (or brain and simulator) have the same structure and processing power, and the same inputs. So, it is assumed, they would have the same thoughts and the same outputs.
    • This would be very unlikely unless the whole system is linear. If it is not, the two brains would butterfly-off in different directions, unless there’s some regulator to bring them back together.
  • But, even were this indeed the case when sharing a body, with different bodies in different situations, the two brains would fly off in different directions and would no longer be functionally equivalent.
  • So, we’d have two distinct psychologies claiming to be Dennett, and the question which is Dennett is still relevant.
Footnote 44: But, Dennett’s FPP would still reside in Yorick – under the illusion of being in control. Hubert – if it has a FPP at all – would have a numerically different FPP (though exactly similar, as the TE is set up).

Footnote 45:
  • There would seem to be four possible pairs of survivors formed from {Yorick, Hubert} x {Fortinbras, Rosencrantz}, though, of course, there can only be two actual survivors. This would depend on the choice.
Footnote 47: It’s not explicit what the offer is. Presumably it’s to have a second body (ie. Rosenkrantz) attached to his spare brain (Hubert).

Footnote 48:
  • And I agree.
  • As noted earlier, Yorick and Hubert are no longer synchronised.
  • As Locke noted – there would be two persons – like the day-person and night-person – with incommunicable consciousnesses.
  • All this fancy has got a bit out of hand.
Footnote 49:
  • Indeed!
  • Dennett doesn’t point this out here, but no-one would know other than the “disembodied” brain cut off from Fortinbras, who would be doubly “locked in”.
  • That is, “he” would not only lose control, but would not receive sensory input either.
Footnote 50:
  • Because, if one brain does become disconnected, then we have two consciousnesses and two people, only one of which can be Dennett.
  • So, he’s self-concerned about the one that’s him, and altruistically concerned for the one that isn’t.
Footnote 51:
  • I’d initially thought the master switch would totally isolate Yorick, but this is not so.
  • Both switches deal with output control only.
  • For Yorick there are two levels, for Hubert only one.
Footnote 52:
  • Well, “Dennett” is always Yorick, and is presently Yorick+Fortinbras.
  • Yorick knows that he is Yorick. So, Dennett knows who he is. He may get confused, but ought not to.
  • The problem is that Hubert also thinks he’s Yorick – or at least acts as though he does.
  • So, third parties have an epistemological problem when listening to Fortinbras. If they don’t know whether Yorick or Hubert is in control, they don’t know whether the mouthpiece (Fortibras) is speaking truly or falsely in claiming to be Dennett.
Footnote 53: This is a qualitative matter, and doesn’t numerically distinguish one Dennett-alike from another any more than “essential VW Golf-ness” distinguishes one from another.

Footnote 54:
  • Well, it’s really from Yorick or Hubert, but “Dennett” doesn’t know which.
  • “Dennett” – the public-facing individual – is either Yorick+Fortinbras or Hubert+Fortinbras, depending on the switch.
  • Yorick knows he’s the real Dennett, basically because he believes he is, and his belief is true, reliably caused and all that.
  • Hubert thinks (wrongly) that he’s the real Dennett, but can never tell.
  • When we had two functionally-equivalent brains, I don’t think either could tell who he was either by introspection or by looking at the switches, as the experiment is set up. Each would experience the world in the same way.
  • The only way then either would know would be if either Yorick or Hubert were destroyed. Then the other would know who he was.
  • Now, however, the controlling brain would know he was in control, so would know who he was by looking at the switches.
Footnote 55: Of course, the “eating” only maintains Fortinbras. Yorick and Hubert have their own means of maintenance – “nutrients” and electricity, respectively.

Footnote 56:
  • Is this suggestion supposed to be serious? How is the random decision to be satisfied?
  • Third parties don’t know whether Yorick or Hubert has been selected to keep Fortinbras, nor which has specified the parameters for the new body.
  • So, they wouldn’t know which to join to which.
  • So, if there was a complaint afterwards, they wouldn’t know who to believe.
  • I suppose, though, they could give the person receiving Fortinbras a code-word, and if whoever gets Fortinbras can’t remember it, assume they have been joined up wrongly and swap them over.

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