Online research in philosophy

As part of his ongoing critique of metaphysical realism, Hilary Putnam has recently argued that current materialist theories of mind that locate mental phenomena in the brain can make no sense of the proposed identifications of mental states with physical (or physical cum computational) states, or of the supervenience of mental properties with physical properties. The aim of this paper is to undermine Putnam's objections and reassert the intelligibility – and perhaps the plausibility – of some form of mind-body identity and supervenience.

Hard materialism claims that the only events are physical events, involving the instantiation of physical properties in physical substances. This however omits all the mental events to which we have privileged access. Soft materialism claims that the only events are physical events and mental events involving the instantiation of mental properties in physical substances. But a list of such events would not tell us which persons had which bodies. Only dualism, which holds that the essential part of each person is a mental substance, a soul, enables us to say which person occupies which body, and so to give a full description of the world.

Elements of Mind (EM) has two themes, one major and one minor. The major theme is intentionality, the mind’s direction upon its objects; the other is the mind–body problem. I treat these themes separately: chapters 1, and 3–5 are concerned with intentionality, while chapter 2 is about the mind–body problem. In this summary I will first describe my view of the mind–body problem, and then describe the book’s main theme. Like many philosophers, I see the mind–body problem as containing two sub–problems: the problem of mental causation and the problem of consciousness. I see these problems forming the two horns of a dilemma. Just as the problem of mental causation pushes us towards physicalism, so the problem of consciousness pushes us away from it. Each problem reveals the inadequacy of the solution to the other. Essentially the problem of mental causation is the conflict between (i) the apparent fact that mental states and events have effects in the physical world and (ii) a general principle about the causal nature of the physical world, which is sometimes called the ‘causal closure’ or the ‘causal completeness’ of the physical world. This principle says that all physical effects have physical causes which are enough to bring them about. The problem then is simple: how can a mental cause have a physical effect if that effect also has a physical cause which is enough to bring it about? Barring massive overdetermination of our actions by independent causes, it seems that the best answer is to identify the mental and the physical causes. And this is traditionally how physicalists have argued for their identity theory of mind and body. However, many physicalists reject the identity theory, and therefore they have to solve the mental causation problem in some other way. At present, there is no consensus among physicalists on which of the currently proposed solutions is correct. In chapter 2 of EM I propose an alternative, which I call ‘emergentism’. Inspired by the rejection of the identity theory, Emergentism is the idea that mental properties are genu..

There are two constraints on any functionalist solution to the Mind-Body Problem construed as an answer to the question, “What is the relationship between the mental properties and relations (hereafter, simply the mental properties) and physical properties and relations?” The first constraint is that it must actually address the Mind-Body Problem and not simply redefine the debate in terms of other, more tractable, properties (e.g., the species-specific property of having human-pain). Such moves can be seen to be spurious by the very multiple-realizability intuitions that motivate functionalism in the first place. For, according to those intuitions, it is possible for a being to experience pain, have beliefs, etcetera, and yet not only to be of a different species, but to have an entirely different material constitution from human beings.

There are two constraints on any functionalist solution to the Mind-Body Problem construed as an answer to the question, “What is the relationship between the mental properties and relations (hereafter, simply the mental properties) and physical properties and relations?” The first constraint is that it must actually address the Mind-Body Problem and not simply redefine the debate in terms of other, more tractable, properties (e.g., the species-specific property of having human-pain). Such moves can be seen to be spurious by the very multiple-realizability intuitions that motivate functionalism in the first place. For, according to those intuitions, it is possible for a being to experience pain, have beliefs, etcetera, and yet not only to be of a different species, but to have an entirely different material constitution from human beings.

Gilbert Ryle accused Descartes of advancing what he called the “paramechanical hypothesis,” according to which the structure and operations of the mind can be understood on the model of the structure and operations of a physical system. The body is a complex machine – “a bit of clockwork” – that operates according to laws governing the mechanical interactions of material things. The mind, on the other hand, according to Descartes (according to Ryle), is an immaterial machine that operates according to formally analogous laws governing the paramechanical interactions of immaterial things – “a bit of not-clockwork.” In other words, mental processes are the same as physical processes, only you don’t have the matter. I don’t know whether Descartes actually thought this. But, surely, if he did, he was making some kind of logical or conceptual error. Mental processes can’t be the same as physical processes, minus the matter, since the matter matters. The properties of physical systems have physical explanations, which are explanations in terms of physical properties and physical laws. But it is absurd – a category mistake – to suppose that mechanical explanations could apply to immaterial things with no physical properties, subject to no physical laws. (If matters of mind..

Argument for Epiphenomenalism [I]: (A) Mental event-tokens are identical with physical event-tokens. (B) The causal powers of a physical event are determined only by its physical properties; and (C) mental properties are not reducible to physical properties.

Mind is not some mysterious mind stuff; no such stuff exists and the universe comprises only physical matter. It is an emergent property of certain complex material entities, not brains alone but whole human beings living and coping in the physical and social world. This thesis involves three ideas: materialism, emergent properties, and intentionality. The first two belong to the mind-body problem and the status of mental properties in the material universe. The third refers to the mind-world relation, the symbiotic relation between subject and object in cognition and experience.

The mind-body problem is the problem of explaining how our mental states, events and processes—like beliefs, actions and thinking—are related to the physical states, events and processes in our bodies. A question of the form, ‘how is A related to B?’ does not by itself pose a philosophical problem. To pose such a problem, there has to be something about A and B which makes the relation between them seem problematic. Many features of mind and body have been cited as responsible for our sense of the problem. Here I will concentrate on two: the fact that mind and body seem to interact causally, and the distinctive features of consciousness. A long tradition in philosophy has held, with René Descartes, that the mind must be a non-bodily entity: a soul or mental substance. This thesis is called ‘substance dualism’ (or ‘Cartesian dualism’) because it says that there are two kinds of substance in the world, mental and physical or material. One reason for believing this is the belief that the soul, unlike the body, is immortal. Another reason for believing it is that we have free will, and this seems to require that the mind is a non-physical thing, since all physical things are subject to the laws of nature. To say that the mind (or soul) is a mental substance is not to say that the mind is made up of some non-physical kind of stuff or material. The use of the term ‘substance’ is rather the traditional philosophical use: a substance is an entity which has properties and persists through change in its properties. A tiger, for instance, is a substance, whereas a hurricane is not. To say that there are mental substances— individual minds or souls—is to say that there are objects which are non-material or non-physical, and these objects can exist independently of physical objects, like a person’s body. These objects, if they exist, are not made of non-physical ‘stuff’: they are not made of ‘stuff’ at all..

The author is interested in computational approaches to consciousness. His reason for working in the field of AI is to solve the mind-body problem, that is, to understand how the brain can have experiences. This is an intricate project because it involves elucidation of the relationship between our mentality and its physical foundation. How can a biological/chemical system (the human body) have experiences, beliefs, desires, intentions, and so on? Physicists have good reasons to persuade us that ours is a material world that obeys physical laws. Once we commit ourselves to this view, it sounds quite bewildering to think that there is a place for independently existing minds in such a world.