On Thu, Oct 13, 2011 at 1:44 PM, Craig Weinberg <whatsons...@gmail.com> wrote:
> http://serendip.brynmawr.edu/exchange/node/1676
> "As stated above, blindsight is seen clinically as a contrast between
> a lack of declarative knowledge about a stimulus and a high rate of
> correct answers to questions about the stimulus (1). People suffering
> from blindsight claim to see nothing, and are therefore unable to
> reach spontaneously for stimuli, cannot decide whether or not stimuli
> are present, and do not know what objects look like. In this sense,
> they are blind. However, they are able to give correct answers when
> asked to decide between given alternatives (1). Studies done with
> subjects that exhibit blindsight have shown that they are able to
> guess reliably only about certain features of stimuli having to do
> with motion, location and direction of stimuli. They are also able to
> discriminate simple forms, and can shape their hands in a way
> appropriate to grasping the object when asked to try. Some may show
> color discrimination as well (2). Subjects also show visual
> capacities, including reflexes (e.g. the pupil reacts to changes in
> light), implicit reactions and voluntary responses (3). "
> Sounds like absent qualia to me.
> "people suffering from blindsight claim to see nothing"
> So Stathis, Jason, Bruno... how do you know that your computer brain
> doesn't have blindsight if it's eyes seem to work? Is it lying when it
> says it can't see, or is it seeing without being able to look at what
> it is seeing?

A person who has the visual cortex of his brain replaced with a
functionally equivalent computer will behave as if he can see
normally, claim that he can see normally and believe that he can see
normally. It is therefore not like blindsight, where the patient has
deficient vision and claims that he cannot see at all. It is also not
like Anton's syndrome, the opposite of blindsight, where the patient
is blind due to a cortical lesion but has the delusional belief that
he can see and walks around stumbling into things. We can imagine a
condition of perfect blindsight in combination with Anton's syndrome:
the patient lacks visual qualia while responding normally to visual
cues and has a delusional belief that he has normal vision. The
problem with that is, there is no way to diagnose it: we could all be
suffering from it and we wouldn't know, so it is just as good as
normal vision.

Stathis Papaioannou

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