alignments are picked when you first start the game, and they can be changed as your character grows and changes, they each mean something. They each represent something, and here they are:
Light: Groups, trust, faith, and following
Dark: Solitude, rest, faithlessness
Good: Honor, Others, Give, build
Evil: Betrayal, Self, take, destroy.
Love: Belief, togetherness, life.
Hate: Crusting, killing, death
Joy: Lust, happiness, physical want.
Pain: Disgust, sadness, sacrifice