Not rationalist per-se, and much more abstract than legible (it is part of a Poetry lecture series), but Laurie Anderson has long been one of my favorite artists, and this is likely of interest (or of enjoyment or some positive experience) to many people here.  10 minutes into the first lecture, she states "We'll start out with two questions.  The first question is 'Why do anything?' and the second question is 'How do you know what's good?'"