Concurrence, in the law, is the simultaneous commission of a crime while harboring the intent to cause harm. It is necessary to prove concurrence in order to successfully argue that someone committed a crime and should be held legally liable for it, except in certain kinds of cases. This concept most commonly comes up in criminal law, although it can be an issue in some kinds of civil cases as well.
The guilty action is known as actus reus in law, while intent to commit crime is mens rea or “guilty mind.” Requiring proof of concurrence is an important part of the criminal system, as it establishes a clear link between the desire to commit a crime and the crime itself.
A case that would meet the standard of concurrence would be one where a contractor, hating a rival, kicks the rival's ladder out from under her while she is working, causing severe injuries. The contractor has exhibited both a guilty mind, and a guilty act. On the other hand, if the rival contractor is simply walking past a job site when a fall occurs, this is not a crime, not even if the contractor expresses glee about the rival's fate. The fallen contractor might not appreciate the rival's gratification about the injury, but no legal wrong has occurred.
The law recognizes that sometimes, a sequence of events clearly leads to harm even if the guilty act and the guilty mind are not necessarily concurrent. In the example above, if Contractor A sees Contractor B fall and is happy about it, this is not a crime, but if Contractor A leaves Contractor B in a position where more serious injuries or death are likely, this will be a crime, even if Contractor A is not present when the secondary injury occurs. Under the logic of what is known as the single transaction principle, the actions of Contractor A clearly led to harm for Contractor B, and the first contractor engaged in those actions with the intent to harm.
Attorneys can use a variety of means to try to establish or disprove concurrence in a given case. Things can become especially challenging when people rely on the single transaction principle, as the defense may argue that a reasonable person wouldn't have assumed an action would lead to further injuries. To borrow from our feuding contractors again, if Contractor A fails to call for aid because other workers are onsite and should have seen the accident, the defense might argue that any injuries experienced are the result of negligence on the part of the work crew for not spotting and addressing the original injury.