I went to high school with a classmate who used to have the Pirsig family over for dinner fairly regularly. Robert Pirsig's father Maynard Pirsig was a law professor at the University of Minnesota, where the classmate's father (and, years later, I) studied for a law degree. I think, having read only Zen and the Art of Motorcycle Maintenance among Robert Pirsig's writings, and after limited personal acquaintance with Maynard Pirsig, that Robert Pirsig takes a lawyer's "that's debatable" attitude as he approaches scientific and philosophical questions, which bogs down his quest for certainty.

AFTER EDIT: I've seen an interesting pattern of drive-by voting on this comment, but I'd like to know more about what other people who are acquainted with the writings of Maynard Pirsig (father) and Robert Pirsig (son) think about the influence of the one writer on the other.