Spencer Hobson isn't even a Know?
My short term memory is foggy - but what I gathered from Travelling at Night footnotes, namely about Stag gate - all the answers you can provide in the footnote suggest he never crossed it. He never tried OR never succeeded.
How is it possible? How could a person so accomplished in the arts (or at least one that lives and acts with secret knowledge for so long) never reach that milestone?
EDIT: Reviewed those two footnotes on Know and Stag Door - it is indicated that he reached the door (did not cross it) and knows Ghirbi. So maybe.. it is his wisdom and very conscious choice not to become a Know.. Or he sucks at riddles.