The Massachusetts Institute of Technology canceled a lecture by University of Chicago associate professor Dorian Abbot after he was targeted by his colleagues and students for defending freedom of expression on campus and criticizing the school’s equity initiatives.

Abbot, who studies climate change and extra solar planets in the university’s Department of the Geophysical Sciences, according to the school’s website, says he took an interest in politics when he began to notice “an increasing number of issues and viewpoints become impossible to discuss on campus,” he wrote in an op-ed published in the news letter, Common Sense With Bari Weiss.