Quote Originally Posted by blitz_king10 View Post
It's an interesting question, though the Farplane has never been properly explained. Rikku's statement could have some truth, since the pyreflies only form images of people when you think of them, but why do only dead people appear? It could be due to the pyreflies that form the images of the people you see are the same ones that once formed the person in question (remember that every creature in Spira releases pyreflies when it dies or is sent).
At the end of X2, (SPOILER)the fayth were able to reform Tidus from pyreflies, and Tidus says that they also gave him back his memories, which would suggest that pyreflies are unique to each individual. They could be reforming as a reaction to the strong feelings of the living, although even those emotions are not enough to reanimate them. That might explain why the the pyreflies which formed Tidus' mom wouldn't be able to make a image of, say, (SPOILER)Jecht, because they are her 'special' pyreflies.