If there are physical objects at “higher-levels” in a strong metaphysical sense, then it suggests a solution to one aspect of the problem of subjective experience vis a vis the physical universe. Namely, how there can be a complex thing such as subjective experience that is physical.
In a recent talk, Ned Markosian, Professor of Philosophy at Western Washington University, said that the main problem with “mereological nihilism” – the view that the only physical objects properly speaking are simples – is its counter-intuitiveness. Instead, he offered an alternative called “regionalism.” (Mereology is the study of part and whole – from meros meaning part.)
How is a mereological nihilist to respond?
The first step is to make a distinction between objects in the everyday sense of the term, and objects in a philosophical or metaphysical sense of the term.
In the everyday sense, objects are identified based on things like whether they hang together in an identifiable way, whether there is some particular use for which they will be picked out, and so on. Scientific uses follow along similar lines.
In this sense of an object, a mereological nihilist need not deny that there are everyday or scientific objects. In this way, the counter-intuitiveness of the nihilist’s position is reduced.
However, the nihilist must add, it turns out that these “objects” don’t have an existence beyond the arrangement of the simples. They are useful conceptual (or perhaps perceptual) devices – shortcuts to help in interacting with the world.
The reason for believing this, is Occam’s Razor – to predict how the everyday objects behave, we don’t need to postulate anything more than simples moving in concert, say. We could say that there are ontologically strong objects above and beyond them, but why not just say that they are conceptually useful but ontologically weak (i.e., not real, i.e., mere devices) objects instead?
To motivate a position like Markosian’s regionalism, then, as opposed to mereological nihilism, it seems that we would need to motivate it beyond “intuitive” reasons that can be handled by mereological nihilism by the definitional split outlined above. To do this, I think that what is required is motivation for believing that there are higher-level physical objects in a strong sense for other-than-causal reasons (as physical science locates objects using causal criteria – to be is to be causal according to physical science – and the causal story seems to be covered at the lower level).
Subjective experience is reason for believing that there are higher-level physical objects, but is it sufficient? The alternatives are: deny subjective experience is real, posit that subjective experience is fundamental (and so a “simple”) in some sense, or say that subjective experience isn’t physical.