A. Not according to my know-it-all friend, who thinks artificial intelligence is far superior to that of an attorney. (I’d hate to embarrass him, so I’ll just use initials.)

When I lamented the complexity of many legal doctrines, G.P.T. boasted that he could explain even the most arcane concept to a 10-year old. Up to the challenge, I asked him to explain the doctrine of res judicata to a 10-year old.

Without as much as a pause, he had me imagine that I was “playing basketball with your classmate, and you disagree about the rules. So you ask the gym teacher what the rules are. The teacher explains that you must dribble the ball rather than run with it. Since you can’t dribble well, you seek a second opinion from a different teacher. But the second teacher says, ‘Sorry, you must follow the gym teacher’s rules.’ That’s a bit like res judicata. Once the rules of a game are established, you can’t go to a different teacher or judge to change them.”

Using my 10-year old mind, I asked, “isn’t that the ‘law-of-the-case’ doctrine?” He promptly concurred and “apologize[d] for the confusion in my previous response. The concept I explained earlier, where a rule established by a judge is final and binding, is actually known as the ‘law-of-the-case’ doctrine, not res judicata. Thank you for pointing that out.”

Taking another shot, he gave the following simplified explanation of res judicata: “Let’s say you and your friend argue over who owns the ball. After hearing your arguments, the gym teacher decides that it belongs to you. If your friend takes the ball again and tells another teacher that it’s really his, the second teacher would say, ‘Sorry, but the gym teacher already decided that it’s not yours. I can’t answer the same question differently.'”

Again, the 10-year old in me objected, “wait, isn’t that collateral estoppel?” Without hesitation, Mr. T (as he’s affectionately known) replied, “You’re right once again,” and apologized for the confusion in his previous response. “The concept I explained earlier, where an issue decided by a court prevents relitigation of the same issue, is actually known as ‘collateral estoppel,’ not res judicata. Thank you for pointing that out.”

On his third try, he illustrated res judicata as follows: “Claiming that your classmate punctured the ball, you complain to the principal, and she finds in your classmate’s favor. If you return to the principal with the same complaint later on, the principal would say, ‘Sorry, but you cannot bring the same claim to me again. Now go back to class.'”

Quite a nifty explanation. But Mr. T was still embarrassed and “apologize[d] again for the earlier mix-up. I hope this explanation clarifies the doctrine of res judicata for you.”

What makes his explanation more impressive is that Mr. T is not a lawyer, is entirely self-taught and has never been to law school. Had he been an actual lawyer, he never would have admitted that he was wrong or apologized three times.