In the last post, I pondered what distinction between the physical and non-physical, noting that I’ve historically resisted the label of “physicalist” or “materialist” maintaining that, if any evidence for the non-physical ever did become available, I’d accept its existence. I finished my post asking what that evidence might look like? And if even asking that question was coherent.
In conversation with someone on that post’s thread, I might have answered my own question. As I noted in the post, what we call empirical evidence is, in fact, sensory perception that can be reliably reproduced or at least corroborated. There’s nothing that says that perception must be based on a physical measurement, although physicality is commonly assumed to be a crucial aspect, particularly after centuries of success with that assumption.
In the comment, I used the example of a ghost in a house. If we received reports of ghost sightings in a house, and we investigated, and found that the ghost appeared reliably or at least with enough frequency that independent and skeptical witnesses reported similar attributes, then I’d be obliged to accept its existence.
However, that doesn’t mean that the ghost is necessarily non-physical. It might simply be a form of matter or energy we’re not familiar with. I’d want the ghost studied. How are people seeing it? Does it reflect or produce photons? If so, then it would seem to be some kind of physical phenomena.
But suppose we discovered that no video camera could capture an image of it, no audio recorder could capture its speech (or moaning, or whatever sounds ghosts make). At this point we’d be faced with a situation where the ghost appeared to be manifesting directly in our minds.
But we’re still not necessarily at the non-physical yet. Does it make a difference if people go into the house wearing shielded helmets of increasingly dense material, or with magnetic pulse generators near their head? Or does adding or removing mind altering drugs make any difference? I’m sure there are a host of similar tests we could conduct.
But after every attempt to situate the ghost within the causal framework of physicality, we might well be faced with a situation where we have evidence for the non-physical. It would be evidence for more than just the external phenomena itself, it would be evidence for some aspect of ourselves, or at least some aspect of the witnesses, being non-physical.
So evidence for the non-physical would have to involve sensory perceptions for which no interaction with the physical universe could be established. Such evidence would indicate phenomena in a completely separate causal framework, for in essence, another type of substance, for some version of substance dualism.
Of course, many people claim to have such evidence, but it never seems to have be reproducible or have independent corroboration. Ghosts and similar phenomena are notoriously fickle and unreliable, and never seem willing to show when skeptics are around.
But if we ever found such evidence, it would indicate the existence of a separate causal framework, a spirit world which many are already convinced exists. All that remains is the non-trivial task of finding such evidence. As always, unless I’m missing something?
In many ways, arriving at this conclusion makes me feel better. It means that the distinction I’ve always made between being a materialist and what I call an evidentialist is a coherent one. I’m a skeptic but a scientific one. Show me evidence for phenomena, and I’ll accept its existence.