Property dualism: objections Michael Lacewing enquiries@alevelphilosophy.co.uk © Michael Lacewing

Substance and property dualism Substance dualism: minds are not bodies nor parts of bodies, but distinct substances Cartesian dualism: Minds can exist independent of bodies, and mental properties are properties of a mental substance Property dualism: there is just one sort of substance, physical substance, but at least some mental properties are a fundamentally new kind of property that are not fixed by physical properties Properties of phenomenal consciousness – qualia © Michael Lacewing

Rejecting physicalism Physicalism: everything that exists is physical or depends on what is physical The only kind of substance is physical The only properties that are fundamental are physical properties – all other properties depend on physical properties Property dualism: some properties of consciousness are not ontologically dependent on physical properties There are natural laws that correlate mental properties with physical ones, but it is metaphysically possible for these correlations to be different © Michael Lacewing

Mental causation Do mental properties have ‘causal powers’? E.g. Do thoughts cause bodily movements and other thoughts? Property dualism doesn’t face the problem that substance dualism does, because mental properties are properties of physical substance But how do mental properties cause physical effects? This is no objection: any fundamental causal relationship can’t be further explained (e.g. how does mass bend space?) © Michael Lacewing

Property dualism and science Objection: if mental properties cause physical effects, this is incompatible with science, esp. neuroscience We don’t have good evidence of this Some interpretations of quantum mechanics support the idea that consciousness has effects © Michael Lacewing

Epiphenomenalism It is appealing to think that every physical event has a sufficient physical cause This is compatible with property dualism if mental properties make no causal difference to the world – epiphenomenalism Physicalism is right about causation, but wrong about what exists © Michael Lacewing

Counter-intuitive Objection: Epiphenomenalism is very counterintuitive Reply 1: it is only some mental properties – qualia – that are epiphenomenal Reply 2: it seems like mental states (e.g. pain) cause physical effects (e.g. crying) because a brain process causes both So the mental state is correlated with the effect, but doesn’t cause it © Michael Lacewing

Natural selection Objection: how and why would epiphenomenal properties evolve? The traits that evolve are ones that causally contribute to survival and reproduction Reply: epiphenomenal mental properties are by-products of traits (brain processes) that make a difference to survival Not all properties are selected for, e.g. a polar bear needs a warm coat, and this turns out to be heavy, but the heaviness doesn’t contribute to survival It’s just a fundamental law of nature that some brain processes are correlated with consciousness © Michael Lacewing

An objection from introspection I know I am in pain, because my belief that I am in pain is caused by my pain. If epiphenomenalism is true, my pain causes nothing. If epiphenomenalism is true, I will believe that I am in pain if my brain processes are the same, even if I am not in pain. So if epiphenomenalism is true, my belief that I am in pain is unreliable, and not knowledge. © Michael Lacewing

Reply Knowledge doesn’t require direct causation Suppose the brain state that causes pain also causes the belief that I am in pain Then I wouldn’t (normally) have the belief without the pain – so my belief is reliable So I know when I’m in pain © Michael Lacewing

A ‘category mistake’ Category mistake: To treat a concept as belonging to a different logical category from the one it actually belongs to E.g. Oxford University; team spirit Ryle: Substance dualism wrongly thinks that the mind is another ‘thing’ It is not a distinct, complex, organised unit, subject to distinct relations of cause and effect (to lose your mind and lose your keys is not to lose two things!) Mental concepts (of ‘states’ and ‘processes’) do not operate like physical concepts The ‘para-mechanical hypothesis’: since physical processes can be explained in mechanical terms, mental concepts must refer to non-spatial, non-mechanical processes This is a category mistake © Michael Lacewing

A ‘category mistake’ This applies to property dualism – it thinks of mental properties as part of the same metaphysical framework as physical and functional properties, only different Experiences are not a ‘something’ with peculiar properties of ‘what it is like’ ‘What it is like’ to see red is given by describing what we see when we attend to a red object ‘Red’ is the colour of the object, not a property of experience Differences between experiences (‘what it is like to see red is different from what it is like to see blue’) are simply differences between physical objects © Michael Lacewing