For philosophers like Metzinger and Dennett, Anton’s syndrome is a refutation of the Cartesian view that we have infallible access to our own phenomenal consciousness (subjective experience).

Patients who suddenly become completely blind due to a lesion in the visual cortex in some cases keep insisting on still being visually aware. While claiming to be seeing persons, they bump into furniture and show all the other signs of functional blindness. Still, they act as if the phenomenal disappearance of all visually given aspects of reality is not phenomenally available to them. For instance, when pressed by questions concerning their environment, they produce false, but consistent confabulations. They tell stories about nonexisting phenomenal worlds, which they seem to believe themselves, while denying any functional deficit with regard to their ability to see.

On a philosophical level, Anton’s syndrome, as a classic example of unawareness of visual impairment (…), presents another striking counterexample of the Cartesian notion of epistemic transparency or any strong transcendentalist notion of phenomenal self-consciousness. I still vividly remember one heated debate at an interdisciplinary conference in Germany a number of years ago, at which a philosopher insisted, in the presence of eminent neuropsychologists, that Anton’s syndrome does not exist because a priori it cannot exist. Anton’s syndrome shows how truthful reports about the current contents about one’s own self-consciousness can be dramatically wrong.

– Thomas Metzinger: “Being no one”

But how do they rule out the possibility that patients experience reality-detached phenomenal visual consciousness, which resembles assumed reality (i.e. non-absurd visual hallucinations)?

In this case, we’re back on the familiar ground of Descartes’ skeptical arguments. Patients would not be mistaken about the content of their consciousness. They just wrongly believe that it is a result of sense impression matching reality.


1 Answer 1


viuser: I think you've provided the solution yourself. Those having Anton syndrome cannot be mistaken about their own presently-experienced mental phenomena (or, if one prefers, mental phenomenalizing), but they can be mistaken about their seeming sensory percepts' actually being sensory percepts instead of being, for example, self-generated mental images.

You are correct to link that to the problem of Cartesian skepticism: If you experienced seeming sensory percepts without there being an external world at all--if you were a disembodied mind but still mentally experienced the same seeming sensory percepts as you have all of your life--how would you know? You would still have direct access to your own seeming sensory percepts; they just wouldn't correspond to anything real outside yourself.

Another possibility is that Anton's syndrome patients simply make false statements that seem to be about what they themselves are mentally experiencing but really are not. That Anton's syndrome patients not only demonstrably cannot see but also confabulate might point to the possibility that the normal connection between the experiencing of seeming sensory percepts and the formation of beliefs about sensation has been broken and somehow replaced by some other mechanism of sensory belief-formation. In that case, it's not that they would be unaware of their own presently-experienced seeming sensory percepts (for they might genuinely not experience them, contrary to their claims), but instead that they would not experience those seeming sensory percepts but would nevertheless form false beliefs about mentally unexperienced sensory percepts because of a defective belief-formation process. In that case, a patient could give "truthful reports about the current contents [of his own] self-consciousness"--truthful because he really had formed a belief, not truthful because he really had mentally experienced seeming sensory percepts.

The more natural-seeming account, though, is the one you put forward: "that patients experience reality-detached phenomenal visual consciousness."

  • I 99% agree, but might there be any deeper reasons we perhaps miss? Because Metzinger & Dennett are … enamoured with Anton’s syndrome!
    – viuser
    Nov 23, 2021 at 19:56
  • viuser: Just looking at what you quoted from them, I am not sure they are not confused. In the first paragraph, they write, "They tell stories about nonexisting phenomenal worlds"--not "They tell incorrect stories about existing phenomenal worlds." They seem to be acknowledging that it is ersatz sensory qualia being reported. But that's different from experiencing sensory qualia and then reporting wrongly about them, so it's hard for me to see why they think there is a violation of "epistemic transparency" regarding mentally experienced sensory qualia.
    – MindWalk
    Nov 27, 2021 at 13:21
  • viuser or anybody else who might know: Should I edit my answer to add what I just wrote in a comment, suitably rewritten (for instance, to add an introductory bit)?
    – MindWalk
    Nov 27, 2021 at 13:24

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