I am looking for short stories whose theme is perception vs reality or appearance vs reality. Any suggestions?
Edward Hoch's (very) short story "Zoo" is a great piece for perception vs. reality. In it, a traveling circus goes from planet to planet, collecting admissions from the citizens of each area. When it arrives back at its home planet, the "exhibits" disembark and pay the circus master, who was charging them for a tour to see "exhibits" first-hand in their natural environment. The perception of the circus-goers is that they are viewing specimens on exhibit, and the perception of the travelers is that they are viewing specimens on exhibit, but the reality is that they are all on display.
Many Flannery O' Connor stories deal with this idea. In "The Life You Save May Be Your Own", a mother and a drifter have different perceptions of the woman's daughter, & the reality is something completely separate from what they both think. In "Good Country People", a young woman's perception of her life and philosophy are challenged by a traveling Bible salesman.
I agree with poster #1 with regards to Ray Bradbury. Any of the stories from The Martian Chronicles would serve well, as they deal with the perceptions of aliens and what it means to be human. Also, stories such as "The Highway" and "The Other Foot" deal with humanity's perception of our place in time and space. Amazing.
Finally, J. D. Salinger's Nine Storieshas some incredible moments of questioning our perception of ourselves, and the ways in which we interpret our consciousness.
There might be a couple of stories that could be interesting. I liked Ray Bradbury's "All Summer in a Day" in terms of its examination of how social perception of reality can translate into what is accepted as reality. Margot claims to know what reality is, but her voice is denied by the social group who locks her in a closet. At the same time, I think that another good example of reality and appearance of reality is seen very well in Chopin's "The Story of an Hour," where Mrs. Mallard perceives reality quite differently when she is told of her husband's death and then has time to reflect and think about it. This new perception of reality is undercut by the fact that her husband didn't really die. Finally, I think Gordimer's short story, "Once Upon a Time," does a great job in exploring how the middle class fear of the outside world helps to shape its reality and its own perception of it.
You might try The Necklace by Guy d. M. It's a story about striving for riches to achieve a certain class and status, but it all comes crashing down to reality in the end.