 Alumni of the University of Toronto's colleges, faculties and professional schools have assumed notable roles in a wide range of fields and specialties.In government, Governors General Vincent Massey, Adrienne Clarkson, and Julie Payette, Prime Ministers William Lyon Mackenzie King, Arthur Meighen, Lester B. Pearson and Paul Martin, and 14 Justices of the Supreme Court have all graduated from the university, while world leaders include President of Latvia Vaira Vīķe-Freiberga, Premier of the Republic of China Liu Chao-shiuan, President of Trinidad and Tobago Noor Hassanali, and First Lady of Iceland Eliza Reid.Economist John Kenneth Galbraith, political scientist David Easton, historian Margaret MacMillan, philosophers David Gauthier and Ted Honderich, anthropologist Davidson Black, social activist Ellen Pence, sociologist Erving Goffman, psychologists Endel Tulving, Daniel Schacter, and Lisa Feldman Barrett, physicians Norman Bethune and Charles Best, geologists Joseph Tyrrell and John Tuzo Wilson, mathematicians Irving Kaplansky and William Kahan, physicists Arthur Leonard Schawlow and Bertram Brockhouse, religion scholar Amir Hussain, architect James Strutt, engineer Gerald Bull, computer scientists Alfred Aho and Brian Kernighan, and astronauts Roberta Bondar and Julie Payette are also some of the most well-known academic figures from the university.