In the first part of the Tanner Lectures on Human Values on Wednesday, University of Pennsylvania Law and Sociology Professor Dorothy E. Roberts rooted recent police violence against unarmed black people in a history of racial discrimination based on perceived biological differences.

The Tanner Lectures, which are delivered at several universities around the country, cover social and intellectual topics pertaining to the human condition—two lectures will be delivered at Harvard this year. University President Drew G. Faust and Harvard Law School Dean Martha Minow introduced the lecture on Wednesday.

Much of Roberts’ research focuses on social justice and bioethics, particularly about black women and reproductive rights. In her talk, she discussed the history of race as a perceived biological category and the arguments used to justify enslaving black people.

“With this system of biosocial thought, scientists kept white people happy,” Roberts said, referring to 19th and 20th century ideas about intelligence, eugenics, and sterilization.

Roberts argued that racial inequality is the result of social and political circumstances and not innate characteristics or traits. American society needs to recognize the role of environmental factors in creating inequality, she said.

“We need a more radical rethinking of the relationship between society, biology, and justice,” Roberts said.

History of Science and African American Studies Professor Evelynn M. Hammonds, former dean of Harvard College, spoke after Roberts’ address. Hammonds praised the “stimulating and rich” speech and discussed the “deep sedimentation of race as biology.”

Hammonds said that, like Roberts, she is “haunted” by the view of black people as “biological and social threats,” which she said is especially evident in present-day interactions with police officers.

She argued that race should be seen as an “ever-changing lens,” or a “transfer point between biology and society.”

Faust briefly introduced the Tanner Lectures at the beginning of the event, calling it “an event both welcome and welcoming.”

Dean of Harvard Law School Martha L. Minow highlighted Roberts’ multi-platform achievements, which include speaking at the National Institutes of Health, delivering a TED Talk, and writing online blogs.

“She understands that for change to happen, more and more mediums have to be used,” Minow said.