What is worth fighting for?

In the novel of Johnny Got His Gun Joe thinks there are certain reasons for which you should fight and certain reasons for why you shouldn't fight. Joe believes that you should fight for something that is true to your heart and something you can see. When I say true to your heart I am saying that Joe believes that it that something you are fighting for is worth more than your life to you then you should fight for it. Joe doesn't see any point in fighting for something that doesn't mean more to you than your life. Joe also thinks that you should only fight for something that you can see like a girlfriend or something like that. He believes that if you cant see the thing that you are fighting for then what is the point. One thing that Joe doesn't think that you should fight for is something that is in words. For example, Joe talks about how you shouldn't fight for words like liberty, freedom, or honor. He says this because he himself is not sure what those words mean and if you are not even sure what the words mean then why should you fight for them. These are the reasons for which Joe believes you should fight and why you should not fight.