A Stanford University artificial intelligence conference invited former Google CEO and Alphabet chairman Eric Schmidt to give a keynote speech next month. But a group of academics, activists, and current Google employees are urging organizers to reconsider the decision — citing Schmidt’s acceptance of censorship in China and his handling of sexual misconduct allegations at Google, among other controversies.

Stanford’s Institute for Human-Centered Artificial Intelligence (HAI) announced Schmidt as one of several keynote speakers at the upcoming AI Ethics, Policy, and Governance conference. This weekend, former Google scientist Jack Poulson delivered an open letter to Stanford. “There have recently been serious and credible inquiries into Mr. Schmidt’s ethical conduct,” wrote Poulson. “I therefore strongly request that his role as a keynote speaker be rescinded. Otherwise, I believe the entire mission of your institute should be called into question.”

The letter was cosigned by over 40 people, including 20 who are listed as current YouTube or Google employees. Poulson himself publicly resigned from Google last year following reports that the company was building a censored search engine for China. Other signatories include professors and researchers from universities like Georgetown and Harvard, as well as the co-founders of GreatFire.org, an organization that opposes Chinese censorship.

In a statement, HAI told The Verge that it would not rescind Schmidt’s invitation. “We hope this conference will be an enlightening example of our commitment to host open and vigorous debates on difficult issues that would benefit from public discussion,” wrote a spokesperson. “Rescinding our invitation to any of those speakers would be anathema to the purpose of the conference, HAI and the university.”

Poulson also posted a personal reply from Stanford professor Rob Reich, the associate director of HAI. Reich objected to the petition. “Eric Schmidt’s role at the conference is not to deliver a standalone keynote,” wrote Reich, but to “engage in a dialogue” with former European Parliament member Marietje Schaake. Poulson was also invited to the conference and said he still plans to attend.

Poulson tweeted that he wasn’t asking Stanford to remove Schmidt from the conference, just to rescind his keynote speaking invitation. “Engagement is good, but his elevation via a keynote implies Stanford’s endorsement of him as an ethical leader,” he wrote. In a response to Reich, he suggested a roundtable discussion would be a better format for discussion, rather than critics “waiting in line to question a keynote speaker.”

Poulson also suggested a potential conflict of interest, since Schmidt has close ties to HAI — he’s a member of the institute’s advisory council, and HAI co-director Fei-Fei Li was formerly Google Cloud’s chief AI scientist. Schmidt himself stepped down as the executive chairman of Alphabet (Google’s parent company) in April, but he remains a “technical advisor” with the company.

Google employees have protested several of the company’s policies and programs, including its handling of sexual harassment cases, its relationship with US Customs and Border Protection, and its work on defense contracts like Project Maven. Last month, the company posted new guidelines on political speech in the workplace — although a spokesperson asserted that “we want Googlers to speak up when they feel something isn’t right.”