Is Knowledge Unchanging?

If knowledge does not change, how and why do we learn? Can we improve our knowledge?

If knowledge changes, why do we revere old texts? Haven’t we evolved beyond ancient ideas?

If knowledge does not change, is all progress an illusion? Are we simply lying to ourselves to create a false sense of meaning? Is our meaning defined by our progress?

If knowledge changes, must we constantly readjust to new realities? What defines those realities, if not our knowledge?