KarinsDad said:
A character class matches its class.
What the heck does that mean?
A rock is a stone?
I interpret this to mean, you a class must fulfill 3 things. For instance, take a fighter:
a) it must be capable of defending the party from damage, thus fulfilling its role
b) it must accomplish it in a way that says "martial" rather than "arcane" or "divine" or anything else
c) it must do it in a way that was "fighter" and not "knight", "swashbuckler","paladin","samurai" or any other class that is similar in concept.
The first two points are fairly easy.
If you are a defender, you have abilities that increase your AC, absorb damage, redirect damage from your allies to you, give you temporary hitpoints, heal yourself, prevent damage directly to your allies, etc.
If you use "Martial" as a power source your abilities come from your skills and training. You do things like leap into the way of attacks, use the proper placed insults to make enemies want to attack you, hit the enemies in spots that hurt a lot and make them angry at you, etc.
However, assuming there are multiple martial defenders at some point, what makes a Fighter different from a Swashbuckler (or something else that might be a better example of a martial defender that I'm not thinking of right now). How can a Fighter accomplish his role in a Martial Defender way without being exactly the same as someone else who is a Martial Defender? What makes a Fighter like a Fighter?
When you really begin to think about, it's a really hard question to answer.