The knowledge argument

Obviously in any system that does perception there will have to be different classes of knowledge. Talking about the different mechanics of acquiring such knowledge seems like an odd way to attempt to disprove something called "physicality".

The question seems to be a mere quibble about the meaning of the word "knowledge". It presumes that there is something special about one of the ways people learn things. Does a recording video camera gain "knowledge" about the colour red when it records a scene with a red object in it? What, if anything, does the camera learn about the shape of a cube it sees? It can learn colour but it can't learn shapes. Should we conclude from this that shape is some sort of special knowledge outside of mere physicality?

> "Because if we allowed ourselves to discard one of the premises we'd have a much harder time motivating this whole ridiculous discussion, and since our livelihood depends on such ridiculous discussions, we're not about to let that happen!"

So saith the Amalgamated Union of Philosophers, Sages, Luminaries, and Other Professional Thinking Persons, eh?

I think the problem overloads the term knowledge.

First, there's knowledge about the external world, the kind which enables you to predict the conseqeuences of your actions and to manipulate the world to achieve desired results. Concretely, Mary will be able to use a, say, hex editor on a BW terminal to "paint" a picutre which a "normal" will recognize as a, say, red poppy flower. She manipulated another person into having the experience of seeing a RED poppy flower.

Second, there's knowledge about your internal world, how you experience things. If Mary is shown the poppy flower picture on a color monitor, she will gain new, experiential, knowledge about how her own body reacts to that particular stimulus. It's a knowledge, but it's not a knowledge that gives her abilities to manipulate the external world in new ways.

The premise of the experiment doesn't account for the fact that each individual is a sum of their past experiences, encoded physically in their brains in some way. One person upon hearing "red" will think about tomatoes, another about blood, yet another about poppy flowers. (I grew up at a place where they were common and we as kids even ate the seeds :))

Thus the premise is false, the fallcy is in the formulation "what goes on when we see ripe tomatoes"; emphasis on we. There is no collective "we" in this case; she doesn't know all physical information shee needs to know in order to manipulate the external world (e.g., knowing whether to draw a poppy flower or a tomato in order to evoke a particular emotional response from a particular individual).

    Nagel takes a slightly different approach.
    In an effort to make his argument more adaptable and relatable, he takes the stand of humans attempting to understand the sonar capabilities of bats.
    Even with the entire physical database at one's fingertips, humans would not be able to fully perceive or understand a bat's sonar system, namely what it is like to perceive something with a bat's sonar.

My car emits a sound while parking in reverse. As the car behind gets closer, the sound is emitted more frequently, and becomes constant under a certain distance. When I'm parking a different car, I'm unable to 'feel' the distance from the next car. It's like being blind.

Except it's not a good argument - if you believe knowledge is equivalent to experience. In order to understand what ammonia smells like I need to understand how the mind as a whole interprets the presence of ammonia. Once you have understood how the mind interacts with ammonia then you know what it is like to experience the smell of ammonia. You might say well, I can imagine how it must feel to understand how the mind works and my internal model of how it must be to understand how the mind works indicates to me that this would not allow me to experience the smell of ammonia. But you would be wrong. Just as the machine in the Chinese room argument understands Chinese and understands that part of the world described within Chinese.