Gadamer's description of openness reminded me of our earlier discussions on the call of conscience and even authenticity. Two quotes that I found useful, "The emergence of the question opens up, as it were, the being of the object" (326) and "Discourse that is intended to reveal something requires that thing be opened up by the question" (326), just as conscience acts to bring one closer to an authentic Self it seems that openness is a way for knowledge to bring itself closer to an authentic knowledge-Self. Open-ness is required for every step in the process of questioning; one must remain open in order to perceive of what one does not understand and then be able to ask a question about precisely what one does not understand and question whether or not that question is worth the question. The question must have direction. All predispositions must be discarded when questioning, "But if what is undecided is not distinguished, or not correctly distinguished from those predispositions that are effectively held, then it is not brought into the open and nothing can be decided" (327).
I am not sure how experience relates to the other three elements–and I'm sure it does–at least not with this reading of Gadamer.