Psion said:
Well, it took four pages to get to mincing the definitions of alignment, at least.
OK ok, I guess we should try to answer your original question and stop going off about whose alignment is better then whose.
1. Have you asked the player what can motivate their character besides personal gain?
2. If personal gain is the only motivation, maybe dangle the idea that there's this really nifty cool magic item. That turns out to be a cheap trinket that the bad guy had hoodwinked folks into thinking was good.
3. Make it a personal challenge. "Defend the town!" "Why, what's in it for me?" "Nothing." "Ehh, then I guess I won't do it." "What you're scared?" Challenge his adventurerhood.
4. Get the other players involved to help with the motivation. Have them try to convince the CN guy to come along.
5. Dirty tricks old man. Common, let's go clear out this dungeon of monsters, it should only take a few hours. Then lead them into world's largest dungeon.
6. Personal ties. Kidnap his {mother/father/brother/sister/son/daughter/donkey}. If he lets the relative go, then the rest of the family gets ticked at him, and you could draw a little plot around that.
7. Peer presure. Common everyone else is doing it. Its fun. You know you want to. It'll make you feel good. (Think of all the antismoking campaigns. Reverse them.)
8. Negative reinforcement. So he doesn't want to do X because there is no reward. Have some NPCs do X. Have X involve the gratitude of the populace like free room and board, free meals etc, or nifty treasure. Either way hopefully he sees that sometimes doing something with no reward gets you a reward anyways.
Shrug. Those are some of my suggestions.
-cpd