Persons and Their Parts 1 Persons and Their Parts CHARLES MARINUS JANSEN A thesis submitted for the degree of Doctor of Philosophy UCL, Department of Philosophy Declaration I, Charles Marinus Jansen, confirm that the work presented in this thesis is my own. Where information has been derived from other sources, I confirm that this has been indicated in the thesis. Charles Jansen 5 Abstract This thesis investigates the metaphysics of human persons. In it, I consider two questions. The first question concerns what types of change we can survive. Here, I ar- gue against the popular ‘wide psychological view’. According to this view, our survival requires the presence of particular kinds of psychological connection between our present and future selves, but does not set constraints on the way in which these connections are realised; it is all the same whether our bodies and brains continue to exist, or whether we are beamed from one place to another by teleportation. I argue that we do not have firm intuitions in favour of the wide psychological view, that the view must be carefully formulated in order to give a coherent account of our identity, and that – when so formulated – it is less attractive than an alternative ‘narrow view’, on which our survival requires the continued existence of the realisers of our mental states. The second question concerns the parts that we have. Here, I defend the thesis that we have humanoid form against the view that we are only the size of our brains. I do so by arguing that many of our mental states are primarily attributable to humanoid entities, and (at best) only derivatively attributable to anything that is presently brain-sized. The picture that emerges from the thesis as a whole is one on which our ‘nor- mal’ or ‘characteristic’ form is humanoid, but we have a central individuating nucleus, whose continued functioning is sufficient for our continued existence. I find this an attractive view, and conclude the thesis by considering its implica- tions for Kit Fine’s account of the nature of material things. 7 Impact Statement As of April 2018, UCL requires an impact statement to be included in all PhD theses, which should describe how the expertise, knowledge, analysis, discov- ery or insight presented in the thesis could be put to beneficial use. This thesis articulates a series of ideas about our nature. The conception ul- timately developed resembles, and builds upon, David Wiggins’ one-time belief that we have an ‘individuating nucleus’, which serves as the ‘seat’ of our men- tal capacities (Wiggins 1967, p. 51), and Mark Johnston’s claim that we could survive as lone brains, though this would be, for us, an uncharacteristic ‘muti- lated’ form of existence. (Johnston 1987a, p. 79). Neither thinker argues for these views in any detail – they simply highlight their feasibility. The novel contribu- tion of this thesis is to indicate how these views naturally emerge from attempts to spell out what is required for us to continue to exist. In this, and much of the methodology pursued, there are clear resemblances to Peter Unger’s defence of his ‘Physical View’ of personal identity (1990). One hopes that by building upon these thinker’s arguments, and articulat- ing the reasons to believe their views, this thesis highlights clear avenues for future research into personal identity, and – further afield – into discussions of the nature of material objets. In connection with the latter, one chapter – chapter 6 – examines Kit Fine’s theory of parthood, and develops a novel objection; I ar- gue that there are objects that Fine’s theory cannot accommodate. A paper based on this chapter has recently been accepted for publication at dialectica. 9 Acknowledgements Mike Martin suggested that I begin my thesis with the joke that I do not know whether what I have written is the same thesis as the one that I set out to write. Fortunately, this is not true; I know that what I have written is not the unwieldy sequence of impressions that I set out to describe. I offer the following list in order to attribute responsibility First, and foremost, I would like to thank my supervisor, Rory Madden. Rory was my first undergraduate metaphysics lecturer, and introduced me to the problems of personal identity around ten years ago. In the years since, he has been impossibly and unfailingly generous with his time and support – ranging from supervisions that have lasted a couple of hours, to weekly skype check-ins towards the end of the writing process. I have also spent terms with three other supervisors – Mike Martin, Daniel Rothschild, and Douglas Lavin. Each term has been well spent, and has allowed me to develop and think through ideas related to the topics discussed in this thesis. My time at UCL has been blessed by a large number of colleagues who are as friendly as they are sharp and engaging. Of these, I would particularly like to thank Showkat Ali, Julian Bacharach, Vanessa Carr, Tony Cheng, Niels Chris- tensen, Nicholas Currie, Catherine Dale, Pete Faulconbridge, Jessica Fischer, Alex Geddes, Androula Kafa, Andrew Knox, Kirstine La Cour, James Laing, Michael Markunas, Rowan Mellor, Polly Mitchell, Oda Ottosen, David Olbrich, Rebecca Rowson, and Anaïs White. Without such kind friends, I think that the process of studying for a PhD would have been lonely and unfulfilling. It has not been so. I would like to thank Laura Silva, Edgar Phillips, and Karoline Phillips for being my closest friends throughout my time as a graduate student. I have also been tremendously lucky to regularly play board games with some friends from before university – Josh Higgins, and Asher Lewis. 11 Acknowledgements I would like to thank my dad, Robert Jansen, my mum, Debra Jansen, and my sister, Caroline Jansen, for their support throughout my time at university. My Oma read and commented on almost all of my undergraduate essays, and has been a source of wisdom, inspiration, and typographic advice throughout my university career. Finally, I would like to thank my partner – Elle Wilkins – for her support, humour, and good grace, in putting up with me through the writing of this thesis. There are also some to thank who lack the capacity to read these acknowl- edgements. Stevie, in particular, has kept me sane (despite her best efforts) over the past months. Thomas and Max acted as writing companions for me through my secondary education, up until earlier this year. I also acknowledge the pres- ence of Hamsner and the sticks. This thesis was written under an Arts and Humanities Research Council studentship, awarded by the London Arts and Humanities Partnership (2015– 2018), and a Royal Institute of Philosophy Bursary (2018–2019). I have also ben- efited, both academically and financially, from engagement as a Postgraduate Teaching Assistant by the UCL Philosophy department for the last 5 years. 12 Contents Introduction 17 1 The Two Psychological Views 21 1.1 The Persistence Question . 21 1.1.1 The Psychological View . 24 1.1.2 The Wide and Narrow Views . 27 2 Persisting with Thought Experiments 33 2.1 Intuition and the Wide Psychological View . 34 2.2 Two Objections to the use of Thought Experiments . 35 2.3 From Thought Experiments to Reference . 39 2.3.1 The Epistemic Response . 39 2.3.2 The Response from Reference Determination . 45 2.3.3 Controversies . 48 2.4 Problems with Thought Experiments . 53 2.4.1 Contrary Evidence . 54 2.4.2 Framing Effects . 56 2.5 The Argument from Possible Societies . 58 2.6 Conclusion . 60 3 Functional Subjects 63 3.1 Shoemaker’s Account . 64 3.1.1 Psychological Continuity . 64 3.1.2 Functionalism . 65 3.2 The Entailment Claim . 68 3.2.1 The Argument . 68 3.2.2 The Circularity Objection . 69 3.2.3 Responding to the Circularity Objection . 70 13 Contents 3.3 The Coherence of Shoemaker’s Account . 73 3.3.1 Teletransportation and Fission . 74 3.3.2 Solutions . 76 3.4 Conclusion . 87 4 The Material Self 89 4.1 The Pure Ego Theory . 90 4.1.1 An Alternative View . 91 4.2 Dainton’s Views . 93 4.2.1 Co-consciousness . 93 4.2.2 The Bridge Problem . 95 4.2.3 The Phenomenal Account . 97 4.2.4 An Initial Tension . 98 4.3 Fragmentation and Recombination . 99 4.3.1 The Cohesion Problem . 103 4.4 Responses to Fragmentation . 106 4.4.1 Experiential Unities . 106 4.4.2 Power Individuation . 107 4.4.3 Location and Laws . 108 4.4.4 Stabilisation and the body . 110 4.5 Fragmentation and Personal Identity . 111 4.5.1 Responses . 114 4.6 Conclusion . 119 5 Disjointness 121 5.1 Setting the Stage . 122 5.2 Lowe’s Argument against Materialism . 126 5.2.1 An Invalid Transition . 128 5.2.2 Carving up the Brain . 129 5.2.3 The Individuation of Mental States . 131 5.3 Derivative and Non-derivative Thinkers . 133 5.3.1 Existence . 135 5.3.2 Narrow Minimalism . 136 5.4 Thinking Subject Minimalism . 138 5.4.1 Characterising the View . 138 5.4.2 Olson’s first objection . 141 5.4.3 Olson’s second objection . 143 14 Contents 5.5 Conclusion . 147 6 The Problem of Overlappers 149 6.1 The Problem of Overlappers . 150 6.1.1 Evaluating the Argument . 152 6.1.2 Two Relationships . 153 6.2 Motivating Thinking Subject Minimalism . 156 6.2.1 Lone Brains . 156 6.2.2 Accounting for Thinking Organisms . 159 6.2.3 Gillett’s Argument .