As he opened his new presidential center on Chicago’s South Side, Barack Obama invoked some of his signature themes of hope over division, while warning of greater isolation, polarization and lack of trust fueled by rapidly advancing AI technology.

What went unmentioned during the three-hour, celebrity filled ceremony was the current political flashpoint: Donald Trump. There was no mention of him. All of the other living former presidents were there, but the current one was not invited.

That said, Obama, in his remarks, alluded to the environment in which his successor has thrived, particularly via social media.

“For us to give up, for us to give in now, after all this country has been through, to cynicism and division, would be a betrayal of our founding ideas, a betrayal of our faith,” Obama said, before a crowd that included many of the alumni from his administration.

“And I remain convinced that the overwhelming majority of Americans feel the same way — that as unsettled as we are, people aren’t looking for perpetual anger and division. They are looking for fairness and common sense and mutual respect.”

Among other things, he pointed to the response of residents of Minneapolis to the Trump administration ICE raids in January, where they “braved frigid temperatures, risking their own safety, standing shoulder to shoulder to look out for their neighbors, and sometimes look out for strangers, because they knew that was the right thing to do.”

The center includes a museum, Oval Office recreation, theater, art installations basketball court and park on a 19-acre campus. The center cost $850 million to build, per CNN, making it the most expensive of all presidential libraries.

Per the Chicago Sun-Times, major donors listed on the wall of the center include Connie Ballmer, Jeff Bezos, Brian Chesky, Reid Hoffman and Michelle Yee, Sean and Alexandra Parker, and Marc and Lynn Benioff. Also listed: Mellody Hobson and the Lucas Family Foundation, i.e. George Lucas.

In his remarks, Obama talked of the promise of the AI revolution but also warned of it contributing to worsening inequality and making it harder “for us to tell a truth from a lie.”

“The future feels uncertain, the ground unstable beneath our feet, and as algorithms keep feeding us a steady stream of distraction and outrage, as only the loudest, most extreme voices get attention, fanning our prejudices, appealing to our basest, most tribal instincts, it’s tempting to give in to cynicism and even despair, to stop trying,” Obama said.

He said, “We start thinking that appeals to democracy and civic participation are corny and old-fashioned and boring and naive, that the very idea of working on behalf of the common good is a sucker’s bet, and that in order for us to win, somebody else has got to lose. I get it. I am not immune to anger or doubt. But I do know this. When we lose faith in each other, when we stop believing that voting matters, that citizenship matters, that our collective voices matter, that how we treat each other no longer matters, then we give away our power to decide our own futures.”

Obama’s presidency grappled with increasing polarization, and in his farewell address in 2017, he talked about continued inequality and racial division.

Obama said that the exhibits at the center “are not meant to evoke nostalgia for some gauzy bygone era, some unattainable past that we can dream about and say, ‘Oh, we miss you Barack.’ They’re meant to remind us of who we can be, remind us of what’s possible, so we can forge ahead, clear-eyed and confident, and do the work that still needs to be done.”