The recent Boston Globe series on OUI cases illustrates the significant disparities that arise as judges, jurors, and everybody else grapple with the notion of what is “reasonable.”

In a criminal trial, the standard of proof is beyond a reasonable doubt. What may be a reasonable doubt for some, may not be for others. The most celebrated illustrations of that fact are the O.J. Simpson case and, more recently, the Casey Anthony verdict.

Despite widespread belief that both juries got it wrong, carefully screened jurors, presumably conscientious and sincere, listened to the evidence, were instructed by a judge on the meaning of reasonable doubt, and unanimously found both not guilty.

Most feel that these were anomalies and that nine out of ten juries, exposed to the same evidence with the same instructions, would have convicted both. This same disagreement over what is reasonable is not limited to courthouses; it can be found wherever human judgment is at play.

Efforts of appellate courts to define and simplify the concept to make it more objective and easier to apply remain elusive and sometimes are even counterproductive. In Massachusetts, jurors are instructed that beyond a reasonable doubt means “proof to a moral certainty.”

The use of a complex metaphysical concept to explain the standard of proof is more confusing than helpful. One could reasonably believe that moral certainty is more like absolute certainty.

There is probably no more complex term than “reasonable.” There is no avoiding the fact that as much as we may hope for an objective standard, there are significant subjective elements in what we consider reasonable.

For example, judges and jurors who drink are likely to be more tolerant than teetotalers of what it means to be impaired by the use of alcohol. Persons injured by another as a result of the negligent operation of a motor vehicle are likely to be more sympathetic to the injured party in a civil suit.

Conflicting trial evidence is not written on a blank slate. It is written on the minds and hearts of human beings whose differing backgrounds and experiences cause it to be absorbed differently.

We may look for a “smoking gun,” but most trials are based on circumstantial evidence that requires interpretation. Even more objective disciplines like math and, particularly, science are open to interpretation.

We all consider ourselves reasonable. Despite widely divergent views on politics, religion, sports, or anything else, both sides are convinced of the reasonableness of their position.

Contained in that analysis are a host of subjective factors including intelligence, education, experience, insight, temperament, personality, and bias. Conservatives consider themselves more reasonable than liberals and vice versa.

For a prospective judge to testify that his personal views will not influence his legal decisions is nonsense, but such testimony is routinely heard at congressional hearings for Supreme Court nominees. It is an act that both sides know is impossible.

The human element, with all its strengths and flaws, remains at the center of all our activity. It is probably more evident in the court system than elsewhere partly because of attempts to minimize its influence.

Although well intentioned, those efforts can only go so far. In the final analysis important decisions must be made by human beings. Science can help, but hopefully it will never reduce “reasonable” to an equation. I’d prefer to take my chances before a judge or jury sincerely trying to do what is right than before a computer.

James W. Dolan is a retired Dorchester District Court judge who now practices law.