I perceive evolution of knowledge not as continually growing and expanding, but as serially destroyed and recreated.
Expansion is a popular chimera of growth. We think of the universe in terms of ever-orbiting away from those centers that we have identified. We think of political change as manifestation of new direction. We think of steps forward in technology as bursting revelations. But are all of these things not brought about by reconfiguring previous conceptions?
Matter is never either created or destroyed, but recycled. On a quantum level, that's almost always true. On a grossly observable level - the level of content - it is created and destroyed all the time. Not a thing has been brought to my attention that would suggest the growth of knowledge proceeding any differently.