There's a famous question that asks whether two people who agree that they are seeing a red object might be seeing (in their respective subjective experiences) different colors. For example, one is seeing the object as red in his private experience and the other is seeing it as blue in his private experience. The idea is that the one who is seeing what the other would call "blue", calls what he sees "red", because he always has done, having been told all his life that this color is called "red". And vice versa: I don't think the idea/question assumes that there is one correct blue or red. It's just that the subjective experiences could be completely different while the stimulus and the utterances are identical. It's a very widely known question/idea even among nonphilosophers.

If I understand Keith Frankish and his consciousness illusionism correctly, he is saying or implying that it doesn't mean anything to ask that, because there is no such thing as a quale. And I am under the impression that Dan Dennett and his heterophenomenology (HP) said or implied something similar, decades before Frankish did.

If I understand HP correctly, it says that subjective impressions are not data, but hypotheseses. Thus qualia do not exist and/or are incoherent concepts, say Dennett and Frankish. The difference in the "experience of color" is a difference between qualia in the example given above, and therefore is meaningless or incoherent according to HP.

But I am not sure whether I have understood Frankish ("An Illusionist Manifesto" https://www.keithfrankish.com/presentations/an-illusionist-manifesto/ and "Lecture 1: The Illusionist Option" https://www.youtube.com/watch?v=Y2n-s6C1iYQ&list=PLhgvALi0LQGXIA7cKNmGNTiQ7dpS-7dLw) and Dennett ("The illusion of consciousness | Dan Dennett" https://www.youtube.com/watch?v=fjbWr3ODbAo and "Daniel Dennett - Consciousness, Qualia and the "Hard Problem": https://www.youtube.com/watch?v=eSaEjLZIDqc&t=101s) correctly.

So my question is whether heterophenomenology (HP) or any other school of thought says that because qualia don't exist,this subjective color question is meaningless, and who was the first to say so. In other words, does HP or any other school of thought say it's meaningless to ask whether the red you see is different from the red I see, because qualia don't exist, and who was first to say it or an equivalent statement, and when?

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    Re "The idea is that the one who is seeing blue calls it 'red' ...": Are you assuming that there is one "correct" blue where you write "one who is seeing blue"? Otherwise, which blue are you referring to? Commented Apr 13, 2023 at 22:51
  • @DanielAsimov No I don't think the old idea assumes that there is one correct blue. I have edited the question to make that clear. Thanks for the feedback. Commented Apr 14, 2023 at 0:03
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    A common view is that the question does not make sense even if qualia do exist. The whole point of them is that they are accessible to the subject only, but to ask the question one needs to "objectify" them so that different subject can "import" other's qualia to compare and contrast them with theirs, as if they were just another object. The conception behind the question is thereby incoherent. The idea that things have strictly non-relational "qualities", which, by definition, cannot be shared and hence compared, goes back at least to Kant, if not scholastics.
    – Conifold
    Commented Apr 14, 2023 at 0:31
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    There is a version of the question which is more meaningful, it involves the same subject experiencing inversion of the spectrum (so the color qualia of tomatoes and cucumbers swap places, for example). That one goes back to Malebranche and Locke, but logical positivists (e.g. Schlick in 1932) once dismissed it as meaningless as well, based on their verificationism, see SEP, Inverted Qualia. However, verificationism is out of fashion nowadays.
    – Conifold
    Commented Apr 14, 2023 at 1:19
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    @MatthewChristopherBartsh having extensively read and listened to both Frankish and Dennett since you first raised the question, my view is that they use other words- illusion etc- to refer to the mental experiences that other philosophers label or attribute to qualia, but they do not deny the experiences. You can have an illusion of red which is different from your illusion of blue, and neither might correspond to the illusions that I label with those words. Commented May 6, 2023 at 12:22

2 Answers 2


I believe the Australian philosopher Frank Cameron Jackson (link) was one of the first to say that. I don't, however, know which schools of philosophy think that.

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    Thanks for answering. So what exactly did he say about it? Because of link rot, it is strongly discouraged at SE to use a link alone like you have done here. Please consider specifying the details as text (not an image, because that is hard for others to copy paste, e.g. into Google or a comment) in your answer. Commented May 7, 2023 at 10:17

This response to the inverted spectrum argument is known as the Frege-Schlick view. The name comes from an exchange between Robert Stalnaker and Sydney Shoemaker (here). I doubt whether the attribution to Frege or Schlick is really accurate, but the general idea fits with Schlick's verificationist outlook.

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