Reasonable Doubt, a central concept in our criminal justice system, can sometimes be difficult to comprehend. But it's critical that jurors understand reasonable doubt because they are the ones applying it to determine guilt or innocence in criminal trials. What follows is a explanation of the key terms and two scenarios to illustrate.

Before a trial begins in California, the judge gives jurors this definition of reasonable doubt: "Proof beyond a reasonable doubt is proof that leaves you with an abiding conviction that the charge is true. The evidence need not eliminate all possible doubt because everything in life is open to some possible or imaginary doubt."

• The way to consider "doubt" is uncertainty. If you as the juror have doubts, then you are not convinced that the defendant committed the crime for which he/she is accused.

• These doubts, though, have to be "reasonable." They can't be derived from fanciful, far-fetched scenarios. Instead they have to arise from plausible alternative explanations.

• "Beyond" in this context means excluding or eliminating.

Thus, when we as jurors put these three terms together, we have this guiding principle: we, as reasonable people, have considered the evidence and arguments and are left with one plausible explanation of what occurred: the defendant committed the crime of which he/she is accused.

Here are two scenarios to illustrate the concept. The first falls short of the standard of "proof beyond a reasonable doubt," while the second meets it.

You take the last can of Diet Pepsi from the refrigerator, place it on the counter, and then go to another room for five minutes to check email. When you return, the can is still on the counter but is opened and half empty. You ask your teenage son, who is reading the sports page at the kitchen table, if he drank it. He says that he did not, that it might have been his siblings or the neighbor kids who were running through the house at the time. Though your son is certainly a suspect, the standard of proof beyond a reasonable doubt has not been met. After further investigation, it is revealed that youngest of your children, who had been running around in the hot sun all day, is the culprit.

A fact pattern like this would be required to meet the standard of proof beyond a reasonable doubt: As you set the Diet Pepsi on the counter and leave the room, your younger children and their friends run out of the house to play in the backyard. When you return to the kitchen, the can is where you left it, but opened and half empty. When you ask your eldest son if he drank your Diet Pepsi, he says that it might have been one of the neighbor kids. You walk over to him and touch both hands, which are cold and moist. You also see drops of moisture on the sports page. Though you didn't see him "commit the crime," no other plausible explanation fits the pattern of facts. You as a reasonable person can conclude that he drank your Diet Pepsi.

It's important to remember that in criminal proceedings the burden of proof falls on the prosecution. The defendant is presumed innocent until the state, in the person of the representative from the district attorney's office, demonstrates "beyond a reasonable doubt" that the defendant is guilty. Anything less and the defendant is considered not guilty.

If you have any questions about reasonable doubt, or other elements of the criminal justice system, call me at (916) 442-1200.