Knowledge is a game mechanic that is unlocked when reaching level 20 in a Profession.
While gaining Experience of any kind a bar will fill up depending on the amount of experience, upon reaching 100% a Knowledge point will be gained which can be spent to unlock a Passive activity. Knowledge points can alternatively be converted into 12 Silver or experience for any skill at level 20 or above. This experience can be boosted by an XP Potion.
It is currently not possible to save up Knowledge points for later, prompting the player to use it even when they have no activity to unlock.