Mind: A Property of Matter by Penelope Rowlatt University College London PhD May 2017 Mind: A Property of Matter Penelope Rowlatt _____________________________________________________________________ Signed declaration I, Penelope Rowlatt, 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.1 1 I am very grateful to those who have assisted me in this work. Paul Snowdon was very helpful and supportive in the early stages of the work, but retired before it was completed. Rory Madden made many useful comments in the following months. My greatest debt, however, is to Luke Fenton-Glynn, for the generosity with which he has given his time and energy in order to pick holes in my arguments and quarrel with my use of words, thereby improving the quality of this work beyond recognition; working with him has been a great pleasure. 2 Mind: A Property of Matter Penelope Rowlatt _____________________________________________________________________ Abstract There are three broad possibilities regarding the basic ontology of mind. It could be a property of matter that reduces to the properties that are studied in physics. It could be a property of matter different from those that are studied in physics. It could be nothing to do with matter. The second of these, known in the literature as non-reductive physicalism, is generally considered by philosophers in limited form with mental states, albeit non- reducible, fully determined by other properties of matter (taken to be ‘emergent from’, and ‘supervening on’, the properties of matter studied in physics). My thesis puts the case for the ontological status of mind being similar to that of the other properties of matter, those studied in physics. The approach lends itself to the proposition that mental states can be causally effective per se, since that is the case for the other properties of matter. This proposition runs counter to the usual assumption in the philosophy literature relating to mental causation known as “the completeness of physics”, which requires that all physical events are fully caused by purely physical (non-mental) prior histories. However, theoretical physicists often propose new phenomena for a variety of reasons. There is a lot in favour of this approach. None of the three anti-physicalist arguments (the knowledge argument, the conceivability argument and the hard problem) cause it difficulties. Effective mental causation means that the reason why creatures with consciousness abound in our world could be that consciousness enables effective decision- taking and so has been selected for by the pressures of survival. Effective mental causation would also explain why people feel as if they have freedom of the will: if mental states are causally effective there would be a sense in which people do have free will. 3 Mind: A Property of Matter Penelope Rowlatt _____________________________________________________________________ Contents Chapter 1 Introduction 9 1.1 The purpose of the thesis 9 1.2 Fundamental assumptions 14 1.2.1 Defining ‘physics’ and ‘physical sciences’ 1.2.2 Causal processes, laws of nature and science 1.2.3 The truth of “statements of fact” 1.2.4 The meaning of “there is only one ‘substance’ …” 1.2.5 The meaning of ‘physical’ and ‘physicalism’ 1.3 About consciousness 25 1.3.1 Defining consciousness 1.3.2 What we are conscious of 1.3.3 Varieties of ‘knowing’ 1.3.4 Relation between consciousness and memory 1.3.5 Structure of the mind 1.3.6 Identifying conscious creatures 1.4 Propositions relating to mental states 41 1.4.1 Conscious mental states exist 1.4.2 There is an epistemic gap 1.4.3 Feelings are necessary for the taking of certain types of decision 1.5 Justification for ‘causally effective property dualism’ 45 1.6 Structure of the thesis 47 Chapter 2 Mind as a property of matter 49 2.1. Introduction 49 2.2 Causally effective property dualism 49 2.2.1 What is property dualism? 2.2.2 Property dualism versus supervenience physicalism 2.2.3 Evidence in support of some form of physicalism 2.2.4 References to property dualism in the literature 4 Mind: A Property of Matter Penelope Rowlatt _____________________________________________________________________ 2.3 Arguments for the completeness of physics 53 2.3.1 The success of physics 2.3.2 The brain decides before we are aware 2.3.3 Conservation of energy 2.3.4 Conclusion 2.4 The case against the completeness of physics 60 2.4.1 The existence of mental states 2.4.2 There is an epistemic gap 2.4.3 Are mental states causally effective? 2.4.4 Physics would not be complete but science could be 2.5 How mental causation might operate 67 2.5.1 Introduction 2.5.2 Hypothetical mechanisms for mental causation 2.6 The three (so-called) anti-physicalist arguments 71 2.6.1 The knowledge argument 2.6.2 The conceivability argument 2.6.3 The hard problem 2.7 Conclusion 70 Chapter 3 Approaches to the nature of mind 81 3.1 Introduction 81 3.2 Substance dualism and Vedānta 82 3.2.1 The existence of mind 3.2.2 An argument for substance dualism 3.2.3 Mental causation with substance dualism 3.2.4 Conclusion on substance dualism 3.3 Reductive physicalism 89 3.3.1 Introduction 3.3.2 The identity thesis 3.3.3 Is consciousness a brain process? 3.3.4 The explanatory gap 3.3.5 Concept dualism 3.3.6 Eliminative materialism and behaviourism 5 Mind: A Property of Matter Penelope Rowlatt _____________________________________________________________________ 3.4 Non-reductive physicalism 111 3.4.1 Introduction 3.4.2 Lewis’ case against the existence of phenomenal facts 3.4.3 Supervenience physicalism 3.4.4 Physicalism, or something near enough 3.4.5 The rejection of over-determination 3.4.6 Naturalistic dualism 3.4.7 Property dualism 3.4.8 Functionalism 3.4.9 Multiple realisation 3.4.10 Emergentism and pan-psychism 3.5 Conclusion 137 Chapter 4 The role of consciousness 139 4.1 Introduction 139 4.2 A role for consciousness 140 4.3 The role of feelings in practical reasoning 143 4.3.1 The action selection problem 4.3.2 What does practical reasoning involve? 4.3.3 Multi-variate decision-taking and awareness 4.4 Practical reasoning as a form of homeostasis 149 4.5 Evidence for the selection of actions through practical reasoning 150 4.5.1 The physical correlate of action selection 4.5.2 What if the ability to experience ‘affect’ is damaged? 4.5.3 The role of consciousness in evolution 4.6 Implications for the ontology of consciousness 156 Chapter 5 Mind and the problem of free will 158 5.1 Introduction 158 5.2 The meaning of ‘determinism’ 158 5.2.1 Determinism 5.2.2 Stochastic causal processes 6 Mind: A Property of Matter Penelope Rowlatt _____________________________________________________________________ 5.2.3 A lack of causal processes 5.2.4 Conclusion on determinism 5.3 The meaning of ‘free will’ 164 5.3.1 The operation of the will 5.3.2 The role of a person’s values 5.3.3 When is the will free? 5.4 The meaning of ‘moral responsibility’ 178 5.4.1 Responsibility 5.4.2 Moral responsibility 5.5 The Consequence Argument 170 5.6 The fundamental facts 172 5.7 The concept of a ‘person’ 172 5.8 The free will problem 176 5.8.1 The apparent paradox at the heart of the free will problem 5.8.2 Can the will be said to be free? 5.8.3 Do we have ‘ultimate moral responsibility’ for our actions? 5.8.4 Conclusion on the free will problem 5.9 Causally effective property dualism and compatibilism 179 Chapter 6 Conclusion 181 References 183 Figures Figure 1 Supervenience physicalism and property dualism 10 Figure 2 Consciousness, attention and memory stores 35 Figure 3 Substance dualism 85 Figure 4 Reductive physicalism and supervenience physicalism 90 Figure 5 An event with two causes 123 7 Mind: A Property of Matter Penelope Rowlatt _____________________________________________________________________ 8 Mind: A Property of Matter Penelope Rowlatt _____________________________________________________________________ Chapter 1 Introduction 1.1 The purpose of the thesis The question of the nature of mind is one of a handful of fundamental questions that relate to our existence which surely everyone must wonder about from time to time. An obvious issue that arises on these occasions is whether mind is something to do with matter, most probably with brains, or whether instead it is quite distinct from matter. If it is taken to be related to matter another question arises: are states of mind, ‘mental states’, part of the physical world, in the sense of being related to nothing more than the properties of matter that are studied in the physical sciences, the approach known as ‘reductive physicalism’, or is this not the case? And if it is not the case, there is yet another question: could there, then, be causal processes which are such that the mental state that we experience as the taking of a decision has a direct effect on our actions through its influence on the properties of matter studied in the physical sciences, or must such a mental state be ‘epiphenomenal’? There are three main possibilities concerning the relationship of mind and matter, and they can broadly be described as: dual substances (with mind a property of a different substance to matter), reductive physicalism (in which mental states are part of the physical world, related to nothing more than the properties of matter studied in the physical sciences) and non-reductive physicalism (where mind is a property of matter that is not related to those properties that are studied in physics).2 My purpose in this thesis is to put the case for a particular form of non-reductive physicalism, one in which mental states (states of which a creature could be conscious) instead of being supervenient on properties of matter studied in physics, as is usually assumed, have an ontological status similar to those properties, as in Figure 1b.