Battery is a general intent offense. This means that the actor need not intend the specific harm that will result from the unwanted contact, but only to commit an act of unwanted contact. This also means that gross negligence or even recklessness may provide the required intent or (in criminal matters) mens rea to find a battery.
The doctrine of transferred intent is also applicable. If one person intends to strike another, but the person moves out of the way to avoid being struck, causing the blow to hit a third person, both an assault (against the second person) and a battery (against the third person) have occurred, in both criminal and civil law.
This is important in the distinction between a battery and an assault. A battery involves actual contact. An assault is, in actuality, an incomplete battery; a person commits an assault if he or she intentionally places a person in apprehension of an impending battery. Conversely, if a persons intended only an assault (to cause apprehension of an imminent battery), and harmful or offensive contact actually occurs, the person has committed a battery as well as an assault.
This is also important in distinguishing accidental conduct. If a person violently slams into a fellow passenger on a moving public bus, there is no liability. But if, on the same public bus, there is only the slightest intentional touching of another, which is harmful or offensive and also non-consensual (such as reaching out and touching a woman’s thigh), a battery has occurred.
Conversely, if there was only an intended assault, as in a person gesturing toward another in a menacing manner, and the person trips and actually crashes into the other person, both an assault and battery have occurred.