My suggestion would be:
Bleibt begierig, bleibt offen.
begierig
differs a bit from the other suggested translations, but I think it is simply wrong to translate it as hungrig
. It is true that terms like abenteuerhungrig
do exists, in which hungrig
is used to express desire, however the short form suggested here does sound more than strange to me. Ultimately, he refers to insisting on a burning desire, an apetite for challenge, one such that claims you and takes hold of you, and thus I ended up with gierig
, and in this case, the slightly milder begierig
. Equally to hungry
, begierig
has the objective negative meaning of strong want for something, yet begierig
does also have a certain amiable and well meaning tone to it. (Er trank seinen Becher begierig aus. - meaning not he was greedily drinking, but he enjoyed it.)
bleibt offen
translates the meaning more than the implication of the word. Obviously bleibt offen
does not reflect the notions of true foolishness, that his saying does not explicitly exclude it. However, it is my point of view that at the core, the foolishness he refers to, is a constructive and creative one, not a genuine one.