The Difference Between Kings and Wizards
In 16th century Europe, many believed that kings ruled by divine mandate and wizards wielded magical powers. With apologies to certain non-secular perspectives, they were wrong. No one ever had divine mandate to rule or powers of the type assumed. Since no one could cast magic spells, we now say there were never any wizards. Since no one had divine mandate to rule, we now say there were never any kings.
Wait, no we don't!
Why the difference? It turns out that able to cast magic spells is an essential property of wizards, but having divine mandate to rule is not an essential property of kings. Denying that anyone has the first property means denying that wizards exist, but denying that anyone has the second property does not mean denying that kings exist. A divine mandate is to kings as pointy hats are to wizards -- stereotypical perhaps, or even universal on a certain way of thinking, but not essential.
Kammerer: "Phenomenally Conscious" Is More Like "Wizard" than "King"
In his recent paper Defining Consciousness and Denying Its Existence: Sailing between Charybdis and Scylla, François Kammerer argues that the relationship between "phenomenal consciousness" and is non-physical and is immediately introspectible (in a certain naturalistically implausible sense) is akin to the relationship between "wizard" and able to cast magic spells. Arguing against my 2016 paper "Phenomenal Consciousness, Defined and Defended as Innocently as I Can Manage", Kammerer contends that non-physicality and immediate introspectibility are implicitly essential to our concept of phenomenal consciousness. Nothing wholly physical could be phenomenally conscious, just like no spellless muggle could be a wizard.
Can "Phenomenally Conscious" Be Defined Without Problematic Presuppositions?
My approach to defining consciousness aims to be "innocent" in the sense that it doesn't presuppose that phenomenal consciousness is, or isn't, wholly physical or immediately introspectible. Instead, I define it by example:
These events share an obvious common property that distinguishes them from non-conscious mental states such as your knowledge, five minutes ago, that Obama was U.S. President in 2010. That shared property is what I mean by "phenomenally conscious". Actually, I prefer to just say that they are "conscious" or "consciously experienced", in line with ordinary usage; but since the term "conscious" can be ambiguous, the jargony term of art "phenomenally" can help to clarify. ("Phenomenal consciousness" in the intended sense is meant to disambiguate rather than modify the ordinary term "consciousness".)
On Kammerer's view, as I interpret it, my "innocent" definition fails in something like the following way: I point to one purported wizard, then another, then another, then another, and I say by "wizard" I mean the one obvious property shared among those men and absent from these other men (here pointing to several people I assume to be non-wizards). Although this might purport to be an innocent definition by example, I am assuming that the first group casts spells and the second doesn't. If no one casts spells, I've picked out a group of men -- and certainly those men exist. But no wizards exist.
The purported wizards might all have something in common. Maybe they are members of the opposing tribe, or maybe they're all unusually tall. Even if we can thus pick out a real property using them as exemplars, that property wouldn't be the property of being a wizard. Similarly for my definition by example, I assume Kammerer would say. If we accept Global Workspace Theory, for instance, maybe all of the positive examples transpire in the Global Workspace; but if they aren't also non-physical and immediately introspectible, they aren't phenomenally conscious, by Kammerer's lights.
A Test of Essentiality: What Happens If We Remove the Property?
Imagine traveling back to a simplified 16th century Europe and convincingly delivering the news: There is no divine right of kings, and there are no magic spells. How will people react?
Likely, most ordinary users of these terms (or, more strictly, the 16th century translations of these terms) will treat divine mandate as inessential to kinghood but spellcasting as essential to wizardry. A few philosophers and theologians might claim that without divine right, kings were never real -- but this would be an unusual stance, and history sided against it.
This method -- removing a property and testing whether the concept still applies -- also works for other terms, regardless of whether the feature is explicitly or only implicitly essential.
Consider the essential conditions for that hoary analytic-philosophy chestnut "S knows that P". Discovering such conditions can require significant philosophical inquiry. Perhaps one such condition is that the true belief that P be non-lucky, in Duncan Pritchard's sense. To test this, we can hypothetically remove the non-luckiness from a case of knowledge. If it was mere luck that you read the showtime in accurate Newspaper A rather than misprinted Newspaper B, then ordinary users (if Pritchard is right) will, or should, deny that you know the showtime. This is just the good old method of imaginative counterexample.
Analogously, we can ask users of the phrase "phenomenally conscious" -- mostly philosophers and consciousness scientists -- the following hypothetical: Suppose that the world is entirely material and introspection is an ordinary, natural, fallible process. Will these ordinary users say (a.) "I guess there would then be no such thing as phenomenal consciousness after all!" or (b.) "I guess phenomenal consciousness would lack these particular properties"?
Those among us who already think that phenomenal consciousness lacks those properties will of course choose option (b). These people would be analogous to 16th century deniers of the divine right of kings.
But also, I speculate, most ordinary users of the term who do think that phenomenal consciousness is non-physical and/or immediately introspectible would also choose option (b). Imagining, hypothetically, themselves to be wrong about non-physicality and/or immediate introspectibility, they'd grant that phenomenal consciousness would still exist. In other words, ordinary users wouldn't treat non-physicality or immediate introspectibility as essential to consciousness in the same way that spellcasting is essential to wizardry (or non-luckiness is, maybe, essential to knowledge).
A few users would presumably choose option (b). But my empirically testable, socio-linguistic guess is that they would be a distinct minority.
Non-physicalists are more convinced that phenomenal consciousness exists than that it is non-physical. Hypothetically imagining the truth of physicalism, they would, and should, still grant the existence of phenomenal consciousness. In contrast, believers in wizards would not and should not be more convinced that there are wizards than that there are people with spellcasting abilities.
Innocence Maintained
Contra Kammerer, even if many people associate phenomenal consciousness with non-physicality and naturalistically implausible introspective processes -- indeed, even if can be established that phenomenal consciousness actually has those two properties -- those properties are non-essential rather than essential.
Kammerer's case against the existence of phenomenal consciousness therefore doesn't succeed. Ultimately, I take this to be a socio-linguistic dispute about the meaning of the phrase "phenomenal consciousness", rather than a disagreement about the existence of (what I call) phenomenal consciousness.
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Related:
"Phenomenal Consciousness, Defined and Defended as Innocently as I Can Manage", Journal of Consciousness Studies (2016), 23, 11-12, 224-235.
"Inflate and Explode", circulating unpublished draft paper, Jan 31, 2020.
"There Are No Chairs, Says the Illusionist, Sitting in One", blog post, Apr 24, 2023.