Through the open doors of Union Chapel on Tuesday night, the night sounds of Oak Bluffs drifted in. A truck, noisy revelers. At one point, two police cruisers passed by, sirens blaring and blue lights flashing on the inside of the church walls.

Inside the chapel it was hot. The pews and the balcony were packed with a diverse crowd, squeezing shoulder to shoulder at the sold-out event. The crowd strained forward a bit to see the screen, where part one of Henry Louis (Skip) Gates Jr. historical account of African Americans over the past five decades was playing.

The four-part PBS series, And Still I Rise: Black America Since MLK, is an unvarnished look at the events which shaped the progress of African Americans, from Selma to Black Lives Matter.

The first part is scheduled to air Nov. 15, but the Vineyard audience got a preview on Tuesday evening. The first program explores the deep divisions within the black community during the clash between those who believed in non-violent protest, and those who advocated seizing power by any means necessary.

Mr. Gates is the Alphonse Fletcher University Professor and Director of the Hutchins Center for African and African American Research at Harvard University, and a prominent summer visitor on Martha’s Vineyard. His talk after the screening was part college lecture, part revival meeting, part humorous observation and part nostalgic Martha's Vineyard experience.

Pews at Union Chapel were packed, shoulder to shoulder. — Jeanna Shepard

Sponsored by the Martha’s Vineyard Film Festival as part of its summer series, the screening followed a week of turmoil across the nation, when two young black men were shot and killed by police officers, their deaths captured graphically on video. Those tragedies were followed by the deaths of five Dallas police officers, shot by a sniper as they patrolled during a peaceful protest.

Mr. Gates spoke at length about the issues highlighted by history, and the spotlight currently shining on events of the past week, including his view that deep divisions within American society are more and more defined as much by economics as race.

He said he was deeply offended by the disdain many people exhibit for, among others, supporters of presidential candidate Donald Trump. He said he viewed that attitude as a hindrance to progress.

“You cannot take people who are afraid, people who are terrified of black people, you can’t make fun of them and bring them around,” Mr. Gates said. “You can’t reduce them to a caricature and cure the problem that is afflicting them. They are afraid. They are afraid their kids are not going to have a better life than they had, which they probably won’t. It’s something we’ve got to solve in this room and on this Island. We have to find a way to speak to the fears of the people who hate us most. Because if we don’t find a way to do it, what we’ve seen in the last week is only the beginning.”

The first comment from the audience came from a seasonal Edgartown resident, recently retired from a 30-year career in the Harris County Sheriff’s Department in Houston, Tex. As an African American growing up in Memphis, he said he remembered first hand the unrest following the assassination of the Rev. Dr. Martin Luther King Jr.

“I’m looking at it from both sides,” he said. “I knew why I went into law enforcement. I saw the injustice when I was growing up.”

The man added that he came to the screening to try and get a grip on the violence of the previous week. “It helped me put things in perspective, and I just wanted to thank you for it,” he said.

“I think we should be thanking you,” Mr. Gates responded, which prompted vigorous applause. “I love the police. I want the police to be right around the corner if somebody’s breaking into my house.”

That remark prompted uproarious laughter. In 2009, Mr. Gates was arrested by a police officer who responded to a report of two black men trying to break into a house. In reality, it was Mr. Gates and his driver trying to force open the stuck front door of his Cambridge home, but it escalated into a national debate over racial profiling, culminating in the “Beer Summit” at the White House. President Obama, Mr. Gates and the officer, Sgt. James Crowley, sat down for a discussion.

On Tuesday, Mr. Gates said that before the high profile meeting with the president, he got a call from former president Bill Clinton, who urged him to meet privately with the officer over a beer. At a local pub, before word leaked that they were there and hundreds of people showed up, the two men had a frank discussion.

“We talked about an hour,” Mr. Gates said. “I asked him why did you arrest me?”

Mr. Gates said Sgt. Crowley explained he had a report of two men breaking into a house. He said he feared that Mr. Gates was one of those suspects, and the other might be upstairs, presenting a danger to him.

“All he was concerned about was going home to dinner with his wife,” Mr. Gates said. “That moved me so much. I certainly understand being frightened.”

Another questioner asked Mr. Gates about his thoughts on “holding the center,” in an atmosphere where extreme views are sometimes the loudest voices heard.

“It’s about protecting the ideal and practice of equal opportunity,” Mr. Gates said. “That to me is the center of what America’s all about. How can we make that possible for more and more Americans? The black upper middle class has quadrupled. At the same time, the percentage of black children living in poverty is about 35, 36 per cent. Guess what it was when Dr. King was killed? About 35, 36, 37 per cent.”

He called those statistics the tragedy and the irony of the last 50 years of black history in America,

“No matter what happened last week, no matter what happened in Ferguson, no matter what happened in Baltimore, it’s the best time in American history to be black if you made it into the middle class. But if you didn’t, you’re still stuck in that cycle of poverty. It’s even worse, in a way, than it was before the civil rights era. We were all in the same boat. You lived in the same neighborhood wether you were a doctor or a janitor. All that changed. The level of despair in the poor community is higher than it has ever been.”

He said with equality comes a responsibility.

“Those of us who have made it have a deep responsibility to fight for more economic opportunity for the black people who haven’t made it, but also for poor white people who haven’t made it. You can’t separate these groups of people who are economically oppressed. Until we do that, until we find economic-based solutions, I think we’re doomed to keep repeating this cycle.”