I just wanted to link to this blog post because even if violence is definitely something negative, she has a point. But I'd rather call it self-defense. When diplomacy fails, and the when the society would rather just watch, my boys should definitely know (as a last resort) how to physically stand up for themselves and the people that will need their help. I'll have them engage in martial arts early on (probably next year). But of course teaching them on principles, when to use force, is necessary.