the difference between appearence and reality is reveald in joe's visit to pip. Discuss

I think you are referring to near the end of the story when Pip finally realizes that being a "gentleman" did not equate to being happy. Pip realizes that his goal to be upper class was largely founded on illusion. He sees that Joe and everything that he represents (home, family, unconditional love) are what is real and important. Pip realizes that his permit of money was an empty existence because it simply wasn't real.