Scott wrote:But you have not shown that communicating 'what it is like' to see light or particular colors is inherently impossible. By inherently impossible, I mean in a way that is different than me describing to my neighbor 'what it is like' to see the pictures on my wall which may be practically unfeasible.
Martian Visitor wrote:Forget about the pictures on your wall and deal with a simpler case. Please attempt to describe now what it is like to see light.
How does me trying to describe what it is like to see light -- and either refusing, failing or succeeding -- determine whether the argument in your OP is fallacious or valid? Please note, a valid argument can have a false conclusion and an invalid argument can have a true conclusion. Note also, that as best I can recall I never said that qualia do not exist (or that they do) but only that your report of a color-blind animal being able to see is not proof that it does exist and that concluding as such is a non-sequitur. (I'm not trying to be rude or personal here, but just making sure we are on the same page so to speak.)
With all that said, I can try to describe how it is to see light but it will take a long time and I will fail to do it completely. Although you have called it a simpler case, I'm not sure how that it is so. The amount of data my eyes, optical system and brain process in terms of what I see is incredibly massive. If I was to be able to translate all that data from just a couple seconds of having my eyes open and looking around into a binary code and then read that code aloud each one and zero at a time I estimate it would take more than a millennium to express that translated data. And that ignores the fact that I cannot consciously discover or comprehend that much data in any practical time-frame that my eye can mechanically take in and translate into nerve signals sent to my brain and then brain can subconsciously process. Just as it is practically unfeasible to completely describe the picture on my wall to my neighbor, I think it is practically unfeasible for me to fully translate all the information my eyes can perceive in a few seconds even if it as so-called simple as seeing a huge wall of one color because that really isn't so simple in terms of all the data being taken in and processed, particularly if we bring feelings and emotions into the matter. But in any case I will try to give my best incomplete summary of what it is like to see light:
Seeing light is like each particle of the surface of everything in front of you, even some things far away, singing its own song. It enables you to feel the presence and even some of the nature of these things, like that scene in the movie Daredevil when it is raining. But it's more than just a 1-dimensional (darkness vs light intensity) aspect imprinted on the 4-dimensional space-time around me. It's a multi-dimensional unbelievable spectrum of different songs being sung by these particles coming together in beautiful scenes full of detail I cannot even being to comprehend. But I can't hear just one of these metaphorical sounds at a time, but rather even the shortest glimpses is like a whole concert. And even when I close my eyes, incomprehensibly complex patterns of flashes occur like the sound of an audience breathing excitedly between songs at a concert reminding of what I have tasted. And even though I compare it to hearing a million songs woven into a fluent but intricate web of incomprehensible information and subconscious understanding, the fanciful constructs in my imagination representing this data feel more like sensing heat than the vibrations that are sound. Although I actually can't see infrared radiation, that's kind of what feels like. Even though heat is sort of a one-dimensional quality in that something is either hotter or colder, in my head it is like an array of different kind of tiny flashes of heat in my forehead coming together to form a visual song with each different note or instrument or volume of that instrument or note being what I might call a color, a shade, a hue and the spectrum is as vast as there are different sound to the ear but again they do not literally sting and rapidly shake like a loud screech but rather more like a flash of heat but with complex, incomprehensible dimensions of difference. It's amazing the way my mind is able to make this woven sheet of countless tiny little flashes each with a unique place in the multidimensional spectrum come to life in a single vibrant, detailed constantly changing, high-def -- oh so high-def -- mental representation. It's incomprehensible the way my brain comes up with a seemingly imaginary representation able to vary in intensity of each dimension of difference in these -- what seem like -- flashes of heat that then blend together to come up with different concoctions. Increase the frequency a little, stretch out the wave length, make it a little darker and you have a whole new -- what a call color represented in my head by a uniquely distinguishable type of --what feels like -- flash of heat. It's like, if you had a kitchen full of inedible ingredients such as sugar, vanilla syrup and so on, but your mind took all in and come up with an infinite array of possible delicious dinners that you tasted all at once and each separate ingredient was represented imaginary in your brain by a different aspect of all the flashes of heat, like a random assignment of representation in some fanciful recreation of the world as it seems according to the incredible data -- too great to be possible to consciously keep in mind -- available to the eyes.
Well, that's my description of what it is like to see light. But I'd say it's not even as complete as writing one 10-word sentence summarizing the history of ancient Rome would express all there is to know about that. I could write a thousand page book in line with I wrote above and I don't think it would be complete. (Indeed, a thousand page book on the history of Rome still wouldn't have all the facts.) Perhaps it's just way to practically unfeasible to explain, even if it is not inherently impossible.