United States Supreme Court Associate Justice Anthony Kennedy (left) Chief Justice John Roberts (center) and Associate Justice Stephen Breyer (center right) walk together during a procession at Harvard Law School campus on Thursday, Oct. 26, 2017. The justices were at the school to open a bicentennial summit. (Steven Senne/AP)

When a law school has educated one of every six justices to ever serve on the Supreme Court, and its alums make up a majority of the current court, a certain amount of gasconade — to use a Harvard word — is to be expected.

So the audience was appreciative Thursday when Chief Justice John G. Roberts Jr. took the stage at Harvard Law School with one former and four current Supreme Court justices and announced:

“A minority of my colleagues send their regrets.”

The boastful gathering of justices marked the 200th anniversary of the law school: HLS in the World—The Harvard Bicentennial is the rather grand name of the summit.

There is often concern expressed about the all-Ivy Supreme Court, sometimes even by the justices themselves. Five graduated from Harvard, three from Yale and Ruth Bader Ginsburg is the asterisk — she went two years at Harvard and finished at Columbia after moving to New York with her husband.

There was no such concern about exclusivity Thursday.

Roberts noted it had once been observed, at a time when Harvard had only one graduate on the court, that “Harvard does not need numbers to make her influence felt.”

He deadpanned: “Now I am sure that remains true today. But why take a chance?”

Taking the stage with Roberts (Class of ’79) were Anthony M. Kennedy (’61), Stephen G. Breyer (’64), Elena Kagan (’86 and also the school’s first female dean), Neil M. Gorsuch (’91) and retired Justice David H. Souter (’66). They were seated just as they are on the court, with Roberts in the middle and the others distributed by seniority on either side.

It was for the most part a lighthearted affair, as they urged one another to tell stories, reflected on their most-admired justices in history and named their favorite professors. Kagan should get a special apple-polisher certificate by volunteering that hers was her antitrust professor — Breyer.

Kennedy said the first year of law school teaches you to “think about ordinary things in a formal way.”

Not long after starting, he said, he was at a market that advertised apples for 10 cents. Kennedy said he gave the man a dime and took two. When the owner objected that they were 10 cents each, Kennedy pointed out that the sign said “Apples,” plural.

“He said, ‘Are you a law school guy?’” Kennedy said.

Gorsuch recalled being “scared to death” when he entered law school but ended up being the “luckiest man I know” because he was hired as a clerk at the Supreme Court by retired Justice Byron White and ended up working extensively for Kennedy.

Gorsuch is the first justice to serve on the court with a former boss, and he praised Kennedy to the skies.

Quipped Kennedy: “You didn’t always do what I told you to do as my clerk. You better start doing it now.”

There was a lot of that, at the encouragement of an entertaining HLS Dean John F. Manning. Everyone wanted to hear about how Justices Breyer and Souter were often confused for each other, and when neither jumped at the chance to tell “the story,” as Kagan called it, Roberts stepped in.

It happened when, once again, someone mistaking Souter for Breyer asked what was best about serving on the Supreme Court. “The chance to serve with Justice Souter,” Roberts described Souter as saying.

The more serious moments were also supplied by Roberts. He said that the school is based upon the principles of the free exchange of ideas and intellectual humility.

“Debate and doubt, not doctrine, are what our school at its best teaches,” Roberts said. “What is the Socratic method, after all, but discussion designed to sow doubt in order to develop insight and understanding?”

He said his court practices that. “We go about our business with the full reservoir of mutual respect.”

Manning quizzed the justices on which former justices they would have liked to have served with or have dinner with. Louis Brandeis, who served on the court from 1916 to 1939, was a popular choice, as was John Marshall, chief justice from 1801 to 1835.

But Roberts said there should be no question about a dinner companion: former president and chief justice William Howard Taft, who clocked in at well over 300 pounds. “You know you’d get a lot of food and it would be good.”

In a “lightning round” of questions, Manning brought up little-known facts about the justices: Kennedy once worked on oil rigs in Canada and Louisiana. Roberts had a summer job in the steel mills. Souter was injured at Harvard in a mock duel, when his friend’s saber slashed his hand. “It was a way to pass the time,” Souter said.

When Manning said that one person on stage had been spotted by the law school’s dean at a Red Sox game the day before a big tax final, Kennedy raised his hand. It was one of his last chances to see Ted Williams play, Kennedy explained, so he and a friend took their books to the game. Kennedy heard behind him the deep voice of Dean Erwin Griswold: “You don’t bring the revenue code to the baseball game.” Kennedy added: “I don’t know if he thought it was a profanation of the code or of the game.”

When Manning said one of those on stage had been voted by fellow law clerks as the most likely to serve on the Supreme Court, Kagan sheepishly raised her hand.

That was an embarrassing fact for someone to reveal, she said, but not the worst that could have come from the game she and the other clerks played that year.

“It was definitely better, she said, “than being voted ‘the first person to be indicted.’ ”