What is the physical?

What is the physical?

Barbara Gail Montero

...But what is it about ghosts that, if they were to exist, would make them non-physical? Is it that ghosts would pass through walls without disturbing them? Millions of neutrinos may be coursing through the wall in front of me right now, yet neutrinos presumably count as physical. Perhaps ghosts would have no mass or wouldn’t take up any space. Yet photons have no mass, and point particles, if they were to exist, would not take up space, yet neither, it seems, should count as counter-examples to physicalism. It even seems unreasonable to exclude from the physical realm things that do not exist in space-time. Physicists have speculatively posited something from which space-time itself emerges, the playfully called ‘zero brane.’ Yet since there seems no reason to take zero branes as nonphysical, we cannot take existing in space-time as a criterionfrom being physical.6Richard Healey sums up the situation well when he says, ‘[the]expanding catalogue of elementary particle states of an increasingly recondite nature seems to have made it increasingly hard for the physicists to run across evidence that would cast doubt on a thesis of contemporary physicalism stated in terms of it’(1979:208). Or, as Bertrand Russell said years before, ‘matter has become as ghostly as anything in a spiritualist’s seance’ (1927/1992:78).7The moral is clear: ghosts,ghost stuff and other pre-theoretically bizarre phenomena are not going to provide viable contrasts to the physical.

Yet, one might be tempted to ask, what is it about the fundamental mental, the fundamental numerical, the fundamental normative that makes them all antithetical to physicalism? If we could answer this question we would be able to arrive at a unified notion of the physical that could make sense of questions about whether anything at all, including irreducible numbers, norms, and minds, is physical. I think there is no answer to this question save for the rather disappointing one that they tend to make some self-called physicalists uncomfortable. But we shouldn’t take this disappointment too much to heart, since as long as we specify what is to be excluded from the dependence base, we can make sense of questions about the ontological status of norms, numbers, minds, and so forth (or at least I have not shown that we can’t). As such, physicalism as a unified general thesis dissolves, while the mind–body problem awaits a solution.

So the physical is nothing more than an act of faith in atheism and anti-spiritualism.