Does anything exist over and above the physical? If so, does it supervene on the physical?

What distinguishes the mental from the physical, and the abstract from the concrete?

Is the physicalist committed to the belief that mathematics is not literally true (i.e., fictionalism)?

Why be a physicalist? Why not a dualist of some kind, or an idealist?


3 thoughts on “Physicalism

  1. Some non-physical events have to exist, like beliefs and desires and sensations, although they might supervene on bodily states. So if physicalism just says only physical things exist, it’s false, but it could be true if it just says everything supervenes on the physical. Why would the physicalist have to think mathematics is false?

  2. I think mental events are physical events. Beliefs, desires, and sensations, as far as all the evidence we’ve acquired is concerned, are coextensive with neural events, and certain features of mental events (e.g. fear or anxiety) can be mapped to features of neural events (e.g. increased activity in the amygdala). This doesn’t mean that we can successfully develop a theory that talks about types of mental events being identical to types of neural events; considerations about animals with different neurophysiology than ours but presumed similar mental experiences and issues of multiple realizability seem to count against this, but these considerations are perfectly consistent with there being an identity relation between the token neural state and the token mental state. The seemingly available objection to the ‘identity between token instances’ view is that mental events and neural events have different properties, and if two objects/events have different properties, then they can’t be identical. However, it’s not clear that they do actually have different properties–mental events and neural events are certainly described with different sets of vocabulary, e.g. we wouldn’t talk about a person’s occurrent thoughts by giving a detailed description of the neural state that person was in–but this fact alone doesn’t speak to the metaphysical independence of mental and neural events; it looks like this is more of a semantic issue. The issue is solved by developing a supervenience thesis that holds between the language used to describe neural events and the language used to describe mental events. How exactly that gets spelled out seems like it’s going to be the work of empirical semanticists and neuroscientists.

    Regarding the issue of mathematics, physicalists seem to be faced with a challenge because mathematics seems to make reference to non-physical, non-mental objects like numbers–the claim “2 is even” seems like it ascribes a property to some abstract object, 2, and that claim can only be true if the abstract object in question exists. We can distinguish between two kinds of physicalism: narrow-scope physicalism and wide-scope physicalism; narrow-scope physicalism claims that everything within the spatiotemporal world is physical, whereas wide-scope physicalism claims that everything that exists is physical. Wide-scope physicalists obviously have to say that mathematics, strictly speaking, is a fiction, albeit incredibly useful, since they think there are no abstract objects. Narrow-scope physicalists, on the other hand, might commit themselves to abstracta so that they can, in accord with the natural sciences, say certain propositions and mathematical statements are true, but then they would seem to owe an explanation for their double-standard and for how they could acquire knowledge of such entities.

    1. Then physicalism is ultimately a hypothesis hingent on empirical evidence? For example, if research showed incongruence (i.e. a breakdown of coextensivity) between neural events and mental events, then the case for physicalism would be undermined. Yet it seems prima facie plausible that it can be determined a priori whether or not it’s possible for there to be empirical evidence of incongruence between the physical and mental.

      After all, it seems as though it must be determined a priori; no amount of empirical evidence can determine whether it’s possible for physical and mental events to diverge. The physicalist says that they cannot diverge, while the “non-physicalist” (broadly construed) says they can. Empirical evidence only says whether they DO diverge. Ultimately, then, physicalism is a modal statement, asserting at minimum the necessary congruence of the physical and mental. Recalling Humeanism, experience does not supply us with the resources for claims about necessity, only impossibility (in other words, experience limits the realm of claims about possibility). So physicalism as a modal statement is apparently not something which is reinforced by empirical evidence, since the important and controversial aspect of physicalism is its modal claim (rather than the descriptive claim about scientific research).


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