This chapter presents an introduction to an experience machine, followed by a thought experiment. It is followed by a short discussion and then a series of questions. Some very clever psychologists have designed an experience machine. People are given an opportunity to be plugged into this machine and experience anything that they want. It is exactly as they would experience in real life but all the time they would be hooked up to a machine and floating in a tank. The questions discussed in the chapter are intended to get the philosophy students thinking about the problems. They have used these kinds of questions in seminars as the questions set for seminars, so they also think that they can be used to spark conversation and discussion. The chapter also gives a cursory sketch of some of the ways in which philosophers have responded to the thought experiment.