Philosophy Ranks
Between your character's Race and Class he will gain ranks in at least three Philosophies: Mental, Physical, and another specific to his class (i.e. Divine, Eldritch, or Martial). While it is possible to gain access to additional philosophies in other ways, your character will typically start out with just the three philosophies.
Philosophy Ranks serve as prerequisites to powers, determining which powers that your character can choose at any particular level. Philosophy Ranks range from 1 to 10, where Rank 1 represents just an introductory knowledge and training in the philosophy and rank 10 represents an in-depth mastery of the philosophy. There is a maximum rank imposed on Philosophies, based on character level.
Determine your Starting Philosophy Ranks
Your character's race will grant at least one rank in both the Mental and Physical philosophies, plus an additional rank in one or the other. For some races, you will be allowed to choose where this third rank is placed while other races will have it predetermined.
Your character's class will grant two ranks in the class philosophy, and then grant you an additional rank to place in any of the three philosophies (i.e. Mental, Physical, or your class philosophy). Most players choose to add this additional rank to their class philosophy, granting them access to stronger class powers, but some choose to increase one of the other philosophies instead (in order to qualify for a power or feat for which they need a higher Mental or Physical rank, for example).
Gaining Philosophy Ranks
You additionally will gain one philosophy rank at every even level, starting at level 2. This rank can be placed in any philosophy in which you have not reached Maximum Rank for your level.