Nihilism

Watch The Big Lebowski when you get a chance...lol it sums up nihilism pretty well, it basically a belief in nothing and denies all existence. But it can also be seen as a belief that destroying of institutions or political systems is what's needed to better the future.

I like Hollywood's answer, but I wanted to add a little too.

I think Nihilism - particularly in Kilmer's case is less about belief in nothing, and more about not believing in conventions or social constructs. He clearly lives by a code - it's just his own.

Take for example his decision to kill the entire blood line of the guys who murdered his family. He could have just killed himself, he could have only killed the people who wronged him, but instead he went to extremes to achieve his own notion of justice.

If he believes in nothing, why does he go on living? Why does he help Dorf's character?

I think Kilmer's trying to portray himself as ubermensch - basically a person of will and power

short answer is:

Kilmers character really isnt a nihilist at all. Nihilism generally means a loss of faith in any (moral) ideals. As in: 'In the end none of the stuff we do matters at all, so why bother?'. Now that is a hard thing to combine with a belief in god and Kilmers last words were something about god and the afterlife.. so he's really just not a nihilist, period.