The book is written in "retrospective first person" for Fred's part, and then "immediate first person" for Miranda's. The way the novel is set up, we get to see the world from Fred's point of view, and because this is abnormal we get a contrast between this and the rest of society. Because we ARE the rest of society, we tend to look through Fred's views, seeing them but not sharing them, and recognise them for what they are. A character who's views are not shared by the majority of readers is called an unreliable narrator.
There is contrast after contrast in The Collector. Fred's views vs. the rest of the world, his account of things vs. Miranda's, Miranda and G.P.'s relationship vs. Miranda and Fred's, and therefore G.P. vs. Fred. Additionally, G.P. is contrasted to Miranda herself (male/female, experienced/inexperienced etc.). There is class contrast between Miranda and Fred.
G.P. is in the novel to let Miranda talk properly, to let her grow. The contrast is that Fred has all the freedom and money ever, and he doesn't grow at all. There is also contrast in that he has a lack of guilt, emotion and Miranda - she has it all, and she hasn't even done anything. Also, there is no follow up on feelings, or sticking with ideas, no GUTS, on Fred's part - again, the contrast is with Miranda.
Miranda DOES grow - she learns that life isn't just black and white, that there ARE betweens, like art/no art.
The book represents the dying of her "life force"; her entries are long and wordy, while at the end they deteriorate.
Fred likes photos instead of real people because "photo's don't talk back." It is shown that he is a child (ego states...) because he needs a routine, he is incapable of sharing, and he sulks frequently. He is trapped by the morals he was brought up with, and society's designated roles for males and females (ie. a BUTTERFLY collector!?!?!?).
- the separation of body and soul - Miranda at the end...
- genetics vs. environment - Fred's "situation".