"The risk of cancellation at Williams College, where I have taught for 12 years, and at top colleges and universities throughout this country, is not theoretical. My fellow scientists and I are living it. What is at stake is not simply our reputations, but our ability to pursue truth and scientific knowledge. If you had asked me about academic freedom five years ago, I would have complained about the obsession with race, gender and ethnicity, along with safetyism on campus (safe spaces, grade inflation, and so on). But I would not have expressed concerns about academic freedom. We each have our own woke tipping point—the moment you realize that social justice is no longer what we thought it was, but has instead morphed into an ugly authoritarianism. For me that moment came in 2018, during an invited speaker talk, when the religious scholar Reza Aslan stated that “we need to write on a stone what can and cannot be discussed in colleges.” Students gave this a standing ovation. Having been born under dictatorship in Brazil, I was alarmed."