Full Idea
Fallibilism is the view, proposed by Peirce, and found in Reichenbach, Popper, Quine etc that all knowledge-claims are provisional and in principle revisable, or that the possibility of error is ever-present.
Clarification
'Fallible' means could be wrong
Gist of Idea
Fallibilism is the view that all knowledge-claims are provisional
Source
Thomas Mautner (Penguin Dictionary of Philosophy [1996], p.194)
Book Reference
Mautner,Thomas: 'Dictionary of Philosophy' [Penguin 1997], p.194
A Reaction
I think of this as footnote to all thought which reads "Note 1: but you never quite know". Personally I would call myself a fallibilist, and am surprise at anyone who doesn't. The point is that this does not negate 'knowledge'. I am fairly sure 2+3=5.