Probable cause is a legal standard that refers to a measure of evidence and it’s used in a couple of different ways. It’s generally defined as enough evidence that would cause a reasonable person to think that it’s likely that something happened or something exists. And it’s used, for example, it’s the standard for a judge to review a search warrant. The judge needs probably cause to believe first that there is contraband or evidence of a crime and probably cause to believe that that evidence will be found in a particular place. In order to arrest someone the police either need an arrest warrant, which would be signed by a judge because there’s probable cause to believe that this individual committed a crime. Or the police can simply make a probable cause felony arrest, for example, they have probable cause to believe someone committed a crime and they arrest them without a warrant. But it’s important that it’s less evidence than it takes to prove a case and its less evidence than it would take to prevail in a criminal case or in a civil case.