While it is interesting, I don't think I understand the connection between this illusion and illusionism.
I can identify the shape of the card, and I can see the marks on it but I cannot tell what color they are; they don’t seem one way or the other. What is the quale associated with the card? If the quale is red or black, then that conflicts with the way the card seems to me. If the quale does not have a defined color, that conflicts with the way my peripheral vision seems to be in full color. In either case, it seems I am deeply wrong, not just about what my eyes can physically process, but about the phenomenal contents of my experience.
You say that you can't tell what the colour is, and it doesn't seem to be one colour or the other. So it seems clear to me that you're having neither a 'red quale' nor a 'black quale'. You say that this conflicts with your impression that your peripheral vision is in full colour, and I guess I just don't see the problem here.
If you were able to accurately identify the colour without consciously seeing it, then that would be a weird, blindsight-like phenomenon, but not a threat to the existence of qualia. You say that you're not able to accurately identify the colour at this point, so the situation is weird in a different way, but still not a threat to the existence of qualia -- only to the coherence of your meta-qualia (specifically your feeling that your peripheral vision is in full colour) with your visual qualia (which don't have a colour attached to the card). I can see how that would threaten a very specific version of qualia realism, but not how it would threaten qualia realism in general.
Sure, let me be more precise. The illusionist position is that I have experiences, but those experiences are not "private, ineffable, intrinsic, and directly apprehensible in consciousness" (Dennett). The only reason to believe that we have qualia (private, ineffable, etc. aspects of experience) is that it seems that way on introspection. But if we can be introspectively wrong about our own experiential states, then why couldn't we be fooled about whether those states are actually private, ineffable, etc.?
My response to the phenomenon is a whole lot of nothing. So we have no colour in peripheral vision. I've known that since childhood. Hardly any cones there, compared with the centre. So what? I find this no more boggling than the Müller-Lyer illusion or the Necker cube.
Things are not what we naively take them to be. Well, wow.
4The Müller-Lyer illusion is a mistake about properties of the world. You see two lines, you think they are the same length in reality, but they aren't. Okay, but that doesn't point out any inconsistency in your experience. It shows that your map doesn't align with the territory, that's all.
The card trick shows that you can be mistaken about the contents of your own experience. That you can believe you are having an experience of red, when in fact you are not having such an experience.
Nobody claims that you have direct access to the territory (well, almost nobody), but some phenomenal realists believe you have near-direct access to your own map, that you cannot be mistaken about the contents of your own experience. If that kind of phenomenal realism seems dumb to you, then you are probably not the intended target of the post!
Our perceptions of our inner experience can be as mistaken as our perceptions of the outside world. Who'd a thunk? This unsurprising (to me) phenomenon moves me not at all towards illusionism about interior worlds, any more than Müller-Lyer and the like move me to illusionism about the exterior world.
It seems like the only reason to disbelieve illusionism is introspection, that it seems not to be the case introspectively. So if introspection can be shown to be flawed, then you should move towards illusionism because it is otherwise the most parsimonious explanation of consciousness. Consciousness otherwise appears to be this weird thing that physics can't account for, despite accounting for everything else.
Meanwhile, illusionism about the exterior world is not the most parsimonious explanation; things do in general behave as though there is a consistent physical world.
I think this is a bit God of the gaps style. Like, first you declare that the feelings are the most fundamental thing you can't ever be wrong about. Then someone points out a situation where you are confused about them. Then, you say that in that situation you felt a confused feeling instead of being confused about your feelings. (hypothetical you here)
You are kind of peeling back layers of you brain that feed you information and declaring them not you.
Crosspost from https://jacktlab.substack.com/p/i-lost-my-faith-in-introspection, originally published Jan 9, 2026.
Epistemic status: confident in experimental results and in updating away from infallibilism, but am far from certain that this is an unsolvable problem for phenomenal realists.
Reading Daniel Dennett’s Intuition Pumps and Other Tools for Thinking, I came across the following demonstration:
Naturally I grabbed a deck of cards and went to a mirror to check it out. As the card entered my peripheral vision, I was disappointed. The card was obviously black. I couldn’t read the number, but that’s to be expected. I drew the card closer and closer to the center of my vision, hoping maybe I could see the illusion at some point, but I didn’t get anything. Sighing, and wondering how Dennett could print such shoddy information, I broke eye contact and my gaze flickered down to the card.
It was red.
I tried again. This time I felt that the card was red, but I was much more uncertain. It was black. And at that moment, illusionism just became a bit more plausible to me.
Why? Didn’t I write a whole post on disanalogies between other illusions, like the illusion of (libertarian) free will, and the supposed “illusion” of phenomenality? Haven’t I ever looked at an optical illusion before?
What surprised me, readers, is not that my visual field is imperfect or that I was unaware of this. It’s that my visual field, even now as I type, seems to be in full color, when it actually isn’t.
Let’s try to use the language of qualia to understand what I saw, and see how it gets perplexing. I’m staring into my own eyes. The red card enters my periphery. I confidently identify it as black; I remember that it seemed black to me. What qualia were associated with my visual experience of the card? I see two possibilities:
I never liked perspectives like #1, even when I was a dualist/idealist. What does it even mean to say that the subjective quality of my experience is red, but it seems black to me? Imagine someone comes up to you and says “I’m going to inflict excruciating pain on you, but don’t worry—you won’t even notice.” If I don’t notice, it’s not pain, and if it’s pain, I notice! If you take #1 to be true, you are already casting serious doubt on introspective access to qualia; if you can misidentify your own color experience, what’s to say you aren’t misidentifying other things?
#2 always seemed like the most coherent picture to me. I can’t be wrong about what I am experiencing, it’s just that the character of the experience may be vague or inaccurate. But when I introspect now, fixating in one point after the card experience, my visual field really does seem to be in full color. While I can sort of identify where it starts to slip into fuzziness and imprecision, I really can’t spot a color difference. So it seems to me like my visual field is in full color. But then when I do the card experiment now, and start way out in my periphery, I can identify a point where I can see the card wiggling but I have no idea what color it is. The card doesn’t seem one way or the other to me. And yet, try as I might, I cannot dispell the sensation of full-color vision.
So: I repeat the experiment, and I pause just as I can identify the motion, I can identify the shape of the card, and I can see the marks on it but I cannot tell what color they are; they don’t seem one way or the other. What is the quale associated with the card? If the quale is red or black, then that conflicts with the way the card seems to me. If the quale does not have a defined color, that conflicts with the way my peripheral vision seems to be in full color. In either case, it seems I am deeply wrong, not just about what my eyes can physically process, but about the phenomenal contents of my experience.
I’ve begun reaching for ways out of this. Maybe I have two conflicting quales, one with phenomenal content equivalent to “your whole field of vision is in color” and one with phenomenal content equivalent to “this card does not have definitive color.” But then that means one quale is… incorrect about the contents of other qualia? So I still can’t trust introspection. Maybe the first quale is just the emotional, intellectual feeling behind my opinion that my visual field is in full color, whereas the second quale has actual color content. But my visual field really seems complete! If this level of seeming is just an emotional reaction or doxastic state, how can I be sure that all my other judgments aren’t? It means I can’t distinguish between types of qualia, so I still can’t trust my introspection.
I won’t say I’ve completely converted to illusionism. I still don’t understand how the “illusion” is compatible with my experience. But now I also don’t understand how introspective access to qualia is compatible with my experience. Even if qualia exist, I’m really unsure what we can know about them even from a first-person perspective. And that makes illusionism look like a much more attractive alternative.
I would encourage others who are on the fence about consciousness to try this experiment and share your accounts with me. I’m really curious!