As this definition indicates, battery protects against intentional invasions of the plaintiff’s physical integrity. No contact is intentional if it is not the result of a voluntary act. If Lopez faints and falls on Jones, Lopez is not liable for battery, because she has not caused the touching by a voluntary act. It hardly seems fair to require her to pay damages to Jones for something she didn’t “do” in any meaningful sense, that is, something that was not the result of her voluntary conduct. Similarly, if Smith pushes Lopez into Jones, Lopez has not acted, and would not be liable for battering Jones. See Restatement (Second) of Torts §2 (defining an act as an “external manifestation of the actor’s will”).
Even if the defendant has acted, however, in the sense of making a voluntary movement, that act may not be intentional as that term is used in the context of intentional torts. Suppose, for example, that Chu fails to look carefully in stepping off a bus, does not see Munoz coming along the street, and bumps into her. Chu’s act of stepping off the bus is intentional in the sense that it was deliberate: She certainly intended to put her foot down and move off the bus, but she did not intend to cause the resulting contact with Munoz. To commit a battery, the defendant must not only intend to act; she must act for the purpose of inflicting a harmful or offensive contact on the plaintiff, or realize that such a contact is substantially certain to result
The word “intent” is used…to denote that the actor desires to cause consequences of his act, or that he believes that the consequences are substantially certain to result from it.
Restatement (Second) of Torts §8A. This definition lets Chu off the hook in the bus case, since her act was not intentional in the intentional tort sense. She did not act for the purpose of hitting Munoz, nor was she substantially certain that she would. The contact resulted instead from her failure to take proper precautions (such as looking where she was going) to avoid hitting Munoz. Chu may be liable for negligence, but she has not committed a battery.
Indeed, the purpose of the intent requirement is to confine intentional tort liability to cases in which the defendant acts with a higher level of culpability than mere carelessness: where she acts with a purpose, or with knowledge that the act will cause harmful or offensive contact to the victim. If Chu pushed Munoz to get her out of the way, she would meet this intent requirement, since she would be substantially certain that Munoz would find such a contact offensive. She would also meet the intent requirement if she pushed her to embarrass her in front of a friend-an offensive contactor to cause her to fall in front of a car, an obviously harmful one.
The intent requirement in the Restatement is disjunctive; that is, it is met either by a purpose to cause the tortious contact or substantial certainty that such a contact will result. Suppose, for example, that Smith heaves a stone at her enemy Jones, though she thinks Jones is probably beyond her range. She is not substantially certain that she will hit Jones, but she acts with the desire to do so. This satisfies the intent requirement; if the stone hits Jones, Smith has committed battery.