5. Two Physicalisms and Two Theories of Events
5.1 Type and Token Physicalism
Property or Type Physicalism is the view that every property of the world we inhabit is physical. Physics uses mathematics, but mathematical properties such as ‘added to 5 is identical to 12’ or ‘is an irrational number’ may not be reducible to physical properties. Type physicalism is not a claim about the nature of mathematics, so the range of properties it is about needs to be restricted in a suitable way. This may not be easy to make precise, but at least restricted to the philosophy of mind, type physicalism is clear enough: every mental property is a physical property. Type physicalism is the same as reductive physicalism. If there were any Cartesian souls, they should instantiate at least some non-physical properties.
Token Physicalism is the view that every particular is physical. This allows for property dualism: there is only one kind of substance, physical substance, but there are two kinds of properties it can instantiate, mental and physical ones. Particular mental states, such as a particular pain, may be identical to particular states of your brain, such as a particular firing of c-fibres, but it may instantiate physiological properties as well as irreducibly mental ones, such as hurting. When coupled with property dualism, token physicalism is also called non-reductive physicalism. The objects token physicalism is about, too, need to be restricted in a suitable way. There may be mathematical objects like numbers that cannot be reduced to physical objects. Restricted to the philosophy of mind, as everything that is physical instantiates some merely physical properties, token physicalism says that everything that instantiates mental properties also instantiates physical properties.
Notice that a Cartesian soul, as it stands in relation to a physical body, would not properties that have a physical component. Descartes’s soul would instantiate the property of being united with Descartes’s body. These properties, however, are not dealt with by physics.
5.2 Events: Particulars or Property Instantiations?
Donald Davidson suggested that the world contains not only particulars like tables and chairs, but also happenings such as explosions, walks and retirements. Davidson gave a semantic argument for this view. The best analysis of sentences containing adverbial modifications uses quantification over events. Consider Davidson’s example ‘Jones buttered the toast with a knife at midnight’. According to Davidson, this is best analysed as ‘There is an event such that it is a buttering of the toast by Jones and he did it with a knife and it happened at midnight.’ Here we use the pronoun ‘it’ to refer to the event. The way we refer to events is just the same as the way we refer to more ordinary objects like the knife, the toast or Jones. Just as the sentence posits the existence of Jones, the toast and the knife as particulars, it posits the existence of an event. We describe events and particulars in exactly the same way. To give more information about the event we can add more conjuncts: for instance ‘it happened in the bathroom’. ‘Jones buttered the toast with a knife at midnight’ entails ‘Jones buttered the toast with a knife’ and ‘Jones buttered the toast’, which, on Davidson’s analysis, is a case of conjunctions entailing their conjuncts: if A&B is true, then A and B are also both true. The thought is that, as we talk about events in just the same way as we talk about other things we consider to be particulars we should consider both to be in the same ontological category.
An alternative view, defended by Jaegwon Kim, is that events are properties instantiated by an object at a time. For instance, the event that it is raining in London on 30 June 2016 is London instantiating the property ‘it is raining in’ on that day. This is motivated by the thought that events are changes: London changes from a place where it is not raining to a place where it is raining on 30 June 2016. A change in an object has something to do with a change in the properties the object instantiates. Two events so understood are identical if they are instantiations of the same property by the same object at the same time. On this view, it is best not to say that events are in the same ontological category as particulars like tables and chairs, as the latter are not instantiations of properties at a time in any natural sense.
5.3 The Relations between Them
Suppose events are particulars. Such events are mental if they instantiate mental properties and physical if they instantiate physical properties. Thus, if mental properties are physical properties, then mental events are also physical events. So if events are particulars, type physicalism entails token physicalism. However, assuming only token physicalism, nothing prevents mental properties from being irreducible to physical properties and events to instantiate both kinds of properties. So if events are particulars, token physicalism does not entail type physicalism.
Suppose events are instantiations of properties at times. If all mental properties are physical properties, then anything that instantiates a mental property at a time also instantiates a physical property at a time, so type physicalism entails token physicalism. Conversely, if every mental event is a physical event, then an instantiation of a mental property by an object at a time is also an instantiation of a physical property by the same object at the same time. By the criterion of identity of events, it follows that this mental property must itself be a physical property: a different physical property would constitute a different event. For instance, if the event is an instantiation of despair by Nils at 18:12 on the 17 April 2016, then the mental property ‘being in despair’ must also be the physical property I instantiate at the time, as required, as otherwise the event would be different. So if events are instantiations of properties at times, token physicalism entails type physicalism.
To sum up, type physicalism entails token physicalism, no matter what events are. If events are instantiations of properties at times, then token physicalism entails type physicalism. If events are particulars, token physicalism does not entail type physicalism. If token physicalism differs from type physicalism, then events must be particulars.
5.4 Anomalous Monism
Davidson’s theory of events as particulars is rooted in his philosophy of language. Davidson also proposed a non-reductive physicalism in the philosophy of mind. Some mental states such as being in pain or feeling sad are properties. Others are expressed by complete sentences, such as believing, knowing, fearing, hoping, wishing that something is the case. According to Davidson, we ascribe these propositional attitudes to speakers on the basis of their linguistic behaviour. To interpret a speaker’s utterance, we need to see them as rational agents, whose actions are largely cogent and whose beliefs are largely coherent. This is the only way in which we can make sense of speakers. It means to treat a speaker as a person. We can explain a speaker’s behaviour on the basis of his beliefs and other propositional attitudes. But the criteria applied here are radically different from any criteria we apply to explain events in the merely physical world. Although we can with some certainty predict when someone will be in pain on the basis of physical occurrences, or what kind of behaviour will follow if someone is hungry, this not true for propositional attitudes. We cannot predict a speaker’s beliefs, desires, hopes, or wishes on the basis of his merely physical environment. Any attempts at such predictions have to take into account prior propositional attitudes, and the prediction lacks the strictness of predictions in the merely physical realm. According to Davidson, there are no strict psycho-physical laws, at least when it comes to mental states expressed by propositional attitudes. The mental is anomalous. Nonetheless, Davidson advocates monism: there are only material things.
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