@The Fallen,
Just to warn you, Tom Robbins writes fiction, but embeds much philosophy into his works. I highly recommend both
Jitterbug Perfume and
Skinny Legs and All as good starting points. Jitterbug has main themes of immortality, love, and freedom, and Skinny has major themes including the Middle East conflict, religion, freedom, art, and aesthetics. The stories that the novels follow are definitely bizarre, but Robbins is a master of the English language, and constructs sentences and passages that are poetic. Not to mention, his philosophical divergences are outstanding.
I forget what book it is in (not one of the two I listed, but I think it is
Even Cow Girls Get the Blues), but Robbins devotes a chapter to a conversation between the Thumb and the Brain, which serve as metaphors for the concepts he is staging a conversation between.