You haven’t established that there is an independent wall yet for you not to be.
I have to my satisfaction. That's sufficient for my purposes.
There is a picture of a wall that you are conscious of. If the picture is a part of you then you are in a sense inseparable from the phenomenon ‘wall’. This is what I would call ‘dependently linked’.
That's just a metaphor without any real meaning. You must be a fan of Heidegger.
You have no way of knowing whether the mental appearance of a wall was caused by your senses so you cannot say you that you ‘knew that already. You have the same problem that Descartes referred to.
I'm satisfied that the mental appearance of the wall was caused by my senses rather than by some malevolent imp. But then it really doesn't matter, so long as everyone else's sense impressions are formed consistently by the same imp.
I see that finally you agree with me and say it here: “I would have no reason to believe that those impressions had any objective validity, just as my dreams are a sense impression for myself alone.”
Once again you fail to see an"if" clause that completely alters the text that you quote. You need to get your vision checked.
I rest my case.
Your case never even got winded.
As for the testimonies of others we know that they can be deceived, mistaken, they can lie, they can be deluded because of the failure of language to describe reality.
Quite true, but then we can usually recognize when someone is deceived or mistaken or lying or deluded, because their descriptions of their sense impressions don't gibe with everyone else's.
You cannot experience their sense impressions only your own so you cannot ‘know’ that they experience the same reality as you. The wall appears as a certain color… there are no colors in the world. The sense of its hardness is created not by the external wall but by your own mind. You have no way of knowing what the external world looks like, if there is one, nor can you even know whether it is a dream or illusion… the only thing you can have is the faith of the testimonies of others… which is just like Descartes' appeal that it’s all OK because ‘God would not deceive me’. You on the other hand have to do the same but in your case other peoples’ testimonies. This is, as you know, of course no proof at all.
It's proof enough. Furthermore, it's largely a matter of indifference to me whether we live in a world of objective reality or Berkeleyan idealism or Kantian noumena so long as everyone acts as if there's an independent reality. You may insist that the brick wall exists only in your mind, but you walk around it just the same. To paraphrase William James, then, what is the "cash value" of your position? How does it alter the way you live? How are you any different from the poor, deluded "naive realists" who walk around the brick wall in the foolish belief that it exists independently of them?