Brute force, or as trainer Tom Benge says, “cubic inches” can make a big difference in a fight. But if your assailant is more versed in martial arts than you or the fight is blade- or projectile-based, you may be making a trip to the E.R. or worse. However, if your assailant can’s see you, he or she will have a much more difficult time harming you, especially if you don’t remain in the same place.