Anderson entered a small restaurant and sat on a stool at the lunch counter. Byng entered the restaurant a few moments later and sat down at the lunch counter next to Anderson. For no apparent reason, Anderson suddenly struck Byng on the side of the head with his fist, knocking Byng to the floor. Byng was seriously injured and hospitalized as a result of the incident. Byng incurred medical expenses and missed three days of work. Byng did not have insurance.

What should Byng do and what principles of law are applicable?