Is physicalism an unfalsifiable position?

Question

A follow up from this question: is materialism a self refuting position

Does physicalism include epistemological principles that make it impossible to disprove by its own standard ?

If I am a physicalist, it should follow that I accept only knowledge based on physical evidence. It would not make sense to accept personal testimony about spiritual illumination, perceptions of ghost or near death experience because it can be dissmissed as hallucination. Personal testimony is not reliable in a physicalist worldview.

Physical, measurable evidence is just more proof that the thing measured is part of the physical world. For example if one takes a picture of a ghost or manage to get a physical track of a spiritual event, say a monk reaching nirvana, a physicalist can dissmiss it as a proof that if ghosts emit physical light they must be physical in nature, and if nirvana is measurable it must have a physical explanation.

Pointing at phenomenons that current physics knowledge can't explain can rightfully be dismissed as a "God of the gaps" fallacy. There is a lot we did not understand in the past that turned out to have physical explanation.

So any evidence a dualist or idealist can produce is either invalid by the standards of physicalism or can be returned as more evidence that physicalism is true. It looks to me like a "Heads I win, Tails you lose" kind of game, which paradoxicaly makes it a position difficult to defend, or at least to convince opponents.

Has this problem been discussed in the literature, or have philosophers proposed a test for physicalism in the form of "such or such would convince me that there is something beyond physical reality" ?

Answer 1

Does physicalism include epistemological principles that make it impossible to disprove by its own standard ?

No, yes, and maybe.

No.

Physicalism is not a theory of epistemology. It is commonly associated with correspondence theory, but they are technically separate things. So any question of the form "Does physicalism include epistemological principles that...?" is automatically answered "no," as physicalism does not include any epistemological principles whatsoever.

Yes.

I suspect you actually meant to ask something more like this:

Is physicalism impervious to falsification within the epistemic framework of methodological naturalism?

This is trivially a "yes," because methodological naturalism deliberately abstains from questioning physicalism. But physicalism is neither necessary nor sufficient for methodological naturalism. Methodological naturalism is, broadly speaking, a subjective opinion. Specifically, it is the opinion that studying supernatural phenomena is not a productive activity, or at least that the scientific study of such phenomena is unproductive. You can hold that opinion despite believing in supernatural phenomena, and conversely someone who does not believe in supernatural phenomena may nevertheless use science to try and debunk them.

It is entirely "fair game" for methodological naturalists to decide that they don't want to investigate physicalism. Personally, I decided a long time ago not to investigate playing the violin. This does not mean that I deny the existence or value of the violin, just that I don't think learning it is a good use of my time right now. This is not a defect in methodological naturalism, let alone in physicalism itself.

Maybe

The vast majority of philosophical positions are not subject to direct falsification, and can provide alternate accounts for the same a posteriori observations. Physicalism is not special in this regard. Dualism is also quite difficult to falsify either scientifically or philosophically, and idealism even moreso. The same is true if we consider other branches of philosophy such as ethics. So perhaps a good answer would be that physicalism is hard to falsify, but physicalism does not make itself hard to falsify when compared with other areas of philosophy.