Two other Elan students testified for the defense that they never heard Skakel confess, further casting doubt on the testimonies of Coleman and Higgins. A probable cause hearing requires that the prosecution produce very little evidence to be successful. It is a hearing to ensure enough evidence exists against the defendant for a trial to take place. Its original purpose was to make sure the government was not prosecuting or harassing a citizen for any reason other than that evidence exists showing that a defendant may be guilty. At a trial, however, the prosecution must prove their case beyond a reasonable doubt.
Reasonable doubt is the keystone of the criminal justice system.
I don't know. As you probably have figured out by now the concept of reasonable doubt is a subjective one, a personal decision to be made by each individual who serves on jury. And it's better that way. If it were any other way, the jury would be deciding the guilt or innocence of the accused not by giving their individual conclusion, but by referring to some kind of chart that tries to define what reasonable doubt is. The ideal jury should be made up of disparate members of the community, each bringing his own personal experience to the courtroom and using that experience to judge the credibility of the witnesses and the reliability of the evidence.