People I have found the cure for arguing if you have more than one child.
Here is the stage...
We just returned from the gym. The kids were looking forward the next activity. It was water week at the gym and we did not know it so the kids did not wear swim suits thus they did not want to get wet. All that to say, they went to the gym to sit on their butts while I experienced burning pain and sweat. :) Anyway, we were home and the girls were fighting and Nicollus was stirring to pick a fight of some sort. I was basically not going to have it.
So I sent Nicollus to mow the yard, and the girls to wash my van. LOVELY Problem solved. They needed something to keep their hearts and hands busy. Nicollus came in drenched in his own sweat. I also received a text from the neighbor who wants to hire Nicollus to mow her yard as well! SWEET!
The girls were very focused and worked well together while washing the car. The reason for arguing is often boredom and the solution is directed activity. While I do realize the importance of a child's ability to self entertain and manage their own behavior at a particular age...it is also important for us to "get in front of" negative behaviors. That means don't wait until your children are failing apart to do something with them...PREPARE for them. We need to be PRO ACTIVE with our children and not reactive. While I was certainly reactive in the situation above. I have since learned to "get in front of" potential negative behaviors.