It was the ghost of rationality itself ... This is the ghost of normal everyday assumptions which declares that the ultimate purpose of life, which is to keep alive, is impossible, but that this is the ultimate purpose of life anyway, so that great minds struggle to cure diseases so that people may live longer, but only madmen ask why. One lives longer in order that he may live longer. There is no other purpose. That is what the ghost says.
Robert M. Pirsig, Zen and the Art of Motorcycle Maintenance: An Inquiry Into Values
ghost, great-minds, life, madmen, purpose-of-life, rationality