Sage Ability
Sage Abilities are skills or schooling that arise from the character's knowledge points, according to which field or study the character possesses. All forms of ability, including crafts, fitness, mental endowments and non-spellcasting powers are encompassed as sage abilities in the game world, and all characters, player and non-player, levelled and non-levelled, will have sage abilities in some capacity, from the lowliest beggar to the most capable monarch. Since a sage ability describes the capacity to do or act in some manner, every form of manner in which one can do or act with skill is included.
Acquiring Abilities
When player characters are rolled and their character classes established, the player chooses a field, and a study in that field, which in turn provides a pre-determined set of things the player is able to do. For the most part, success in employing a sage ability is a given. For example, a character with the sage ability to swim does not need to roll a dice to see if they are able. Many sage abilities express knowing rather than action. For example, a character is able to recognize a type of mineral or has intimate knowledge of the region's geography. These things round out a character's relationship with the game setting, defining what they know and what they can do — and likewise defining what those without the sage ability cannot know or do. For example, if a character does not possess the swimming sage ability, they cannot swim.
Initially, player characters will possess only enough knowledge to rate as an "amateur" in their chosen sage study, and not even that in most other things. It requires 10 knowledge points to be considered an amateur. As an amateur, the character gains two or more sage abilities. Thereafter, as the character progresses in experience levels, they will gain more knowledge points, scattered across multiple studies. As these knowledge points accumulate, the character will become an amateur in other studies, acquiring more sage abilities.
Additionally, once the character acquires 30 points in a particular sage study, the character becomes an "authority." This unlocks more sage abilities in that study, which the character will now be able to use. As the character becomes an authority in other studies, this unlocks further sage abilities. With experience levels, the character becomes more and more capable and knowledgeable about things related to their character class and sage fields. This progresses even further when the character becomes an "expert" (60 knowledge points) or a "sage" (100 points). Progressively, the character transforms from knowing a few things, to becoming extremely accomplished and knowledgable about everything having to do with their character class.
This does not involve any sort of point-buy system. Any character that progresses in levels will eventually gain every amateur and most authority-level sage abilities associated with that class. The order of gain, and how far the knowledge can progress, does depend on early choices the player makes about their character.
Non-Player Characters
Levelled non-player characters gain abilities just as player characters do, though most likely there will be little need to pre-determine the extent of an NPC's knowledge, except with characters who are of great importance in a campaign.
Non-levelled non-player characters will possess only one or two sage abilities, without further knowledge surrounding a sage study and with very little capacity to improve their knowledge points. For example, cooking is a sage ability; an ordinary cook will possess that ability, but would be unlikely to expand it. That is because non-levelled persons obtain knowledge in a particular ability through previous one-time training they've obtained, and not through investigation.
Gaining Additional Abilities
All persons, regardless of their class or levelled-status, can be trained in any amateur sage ability through instruction. For example, an individual without any previous knowledge, and without the need to accumulate experience points, can be taught how to swim or cook, as these are both amateur-status abilities. A person cannot be learn to be an authority or higher status without first being trained to become a levelled character (which is also possible through instruction).