(chuckles) I love this argument. It's only happened how many hundreds of times on different threads?
How 'bout this for a definition for violence (and food for argument--I mean thought
Violence is the act of forcing your will upon another person.
And, ya know, for all of you that try to make violence a completely subjective and empirically self-existent thing, don't forget that violence (even if it is a noun) does not exist on its own. It is not some thing that just _is_. In order to have violence, you have to have someone with the intent to be violent first (and it's that many people have this intent that makes violence seem like a subjective "thing" (a.k.a. a "noun")).
For the abusive parent, his intent isn't to discipline a child to help it grow. It's to get the "little bastard to shut up!!"(example, not a specific quote) or behave in some way which the abusive parent will find less stressful. The intent in this case is a completely selfish, "I don't want to deal with this child or take the time to be understanding and nurturing so I am going to take the quickest possible method that gets results." And because of the selfish, forceful basis of the intent behind the punishment, violence (abuse) results.
Pretty simple, really. Take a look at any situation and look specifically at the intent of an action. That's the tell right there. Violence is a "thing" that is very much tied up in, and results from, emotions, especially selfish and dominating ones.
As for martial arts techniques, they aren't violent. They are tools. It's how you use them that matters, not what they can do. I have a swiss army knife I carry everywhere. I could pull out the blade, stab someone a few times, pull out the corkscrew attachment and poke the person's eyes out, and then pull out the saw attachment to saw their head off to keep as a trophy. Is that violent? Ohhhhh yeah. That's why I only use it to cut open boxes and fix things.
So. When you use a technique on someone, do you want to maim, destroy, and make the person utterly submit to you, or do you want to keep them from harming you and do the _best_ _you_ _can_ to keep them from harming themselves as well?
As for just dodging the punch and letting someone hurt themselves, don't forget that it is perfectly ethically acceptable to allow someone to suffer the negative consequences of their own negative actions. If someone attacks me without provocation and I accidentally (remember intent) break their arm, oh well. They screwed up and decided to be violent and now they have to deal with the consequences. I'll probably feel bad afterward, but I didn't (in this hypothetical example. I don't know that I'm enlightened enough to react non-violently in a real situation) intend to add more punishment than what the attacker already subjected themself to the possibility of.
I like the example in the dojo of an accident happening and someone getting hurt. Do you consider that a horrible, violent act, or just a simple mistake and go on with training? Maybe it has more to do with control. Maybe violence is just a lack of control, especially of negativity, selfishness, and the need to dominate others.