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.
