Dualism
Dualism asserts that mind and matter are fundamentally different. Either they are distinct substances, substance dualism, or they are distinct properties of a single substance, property dualism.
Each of them allows for the possibility of phenomenal consciousness and free-will, which physicalism does not, but at the cost of not having an explanation of how these things arise or how the two different substances, or different sets of properties, can interact. The prevailing physicalist belief, although unproven, is that the Laws of Physics for a closed system. If dualism is true, and mind is able to interact with matter, then that postulate must be false.
The advantages of dualism are that it is how the world is normally observed. Instinctively we do not identify with our bodies, rather we say we have a body not that we are our bodies. [Bloom 2005] describes experiments which show that babies and young children are instinctive dualists who are aware of a difference between agents and objects.
At first sight. the mind and the body, or mind and material are seen to be distinct in the following ways:
- Material objects are located at specific points in space and have a size and shape, thoughts and experiences are not. It is not meaningful to talk about the shape of happiness or the location of a desire. Even the location of pain is non-specific even though it may seem otherwise, cf. phantom pain.
- The quality of an experience is different from that of a material substance. For instance the feeling of pain is nothing like anything we can observe physically.
- Mental experiences are not directly accessible to anyone other than the one experiencing them. The only way one person can know that another is in pain is indirectly, either by testimony or by interpretation of behaviour. However the sufferer may be lying or acting. One’s own pain is not open to such uncertainty. If we feel pain then we are in pain, by definition. In contrast to that, the physical properties of an object are open to public scrutiny.
Dualism comes in two main varieties.
- Substance dualism ([Papineau 2002] 1.1)
- Asserts that there are two fundamentally different substances in Nature, the material and the mental. This view, which was famously put forward by Descartes in 1649 [Decartes 1649] and elements of which can be found in Plato, is rarely found today other than in religious believers. According to this view, we are the “ghost in the machine” or the pilot at the controls of a vehicle with sophisticated mechanical and automatic control systems.
- The main problem with this view is that it provides no explanation of how the mind and the material body can influence each other. It is believed, by most, that the laws of Physics form a complete closed system so that there is no way for something non-physical to influence the behaviour of the material world.
- Although Cartesian dualism is very much out of favour, these difficulties do not mean that substance dualism has to be false. Because we do not yet know how two different substances can interact, does not mean that they cannot. Very different types of physical substance interact, such as photons and charged particles, and although much is known about the physical laws which describe the interaction, it is not known how that happens.
- For there to be an interaction between mind and material, the widely held, but unproven, belief that the Laws of Physics form a closed system would have to be false.
- It is true that substance dualism explains little but, when it comes to phenomenal consciousness, that is true of all other theories as well.
- Property dualism ([Papineau 2002] 1.4)
- Asserts that there is only one type of material but that this material may have both physical and mental properties. In one form of property dualism, mental properties can be found in all matter, even individual atoms, in an analogous way to which electric charge can be found in elementary particles. It is only when matter is arranged in a certain way that electrical effects, or mental effects, are observed. This view, known as panpsychism [Benton 2024] or panprotopsychism, is held by a number of workers. Chalmers described this theory, which he calls Type F Monism, as stating that, “phenomenal or proto-phenomenal properties are located at the fundamental level of of physical reality and in a certain sense underlie physical reality”[Chalmers 2010]. Russell also [Russell 1927] expressed this view in 1927.
- The advantages and problems are similar to those of substance dualism. Instead of the interaction problem between mind and matter, there is an equally unsolved, interaction problem between mental and physical properties of the one substance.
- The main difference between property dualism and substance dualism is that, for the former, there cannot be disembodied minds. The relationship between mind and material may be analogous to that between information and matter. Information, in itself, is non-physical, but it can only exist in conjunction with a material substrate. Such as ink and paper or a computer disk.