One of the world's leading theorist in Cosmology, Professor Ellis delivers the 2017 Tanner Lecture on Human Values Professor Ellis is the Emeritus Distinguished Professor of Complex Systems in the Department of Mathematics and Applied Mathematics at the University of Cape Town, South Africa. He is one of the world's leading theorists in cosmology and co-wrote the seminal work on general relativity theory “The Large Scale Structure of Space-Time” with Stephen Hawking. He is a Quaker and in 2004 he won the Templeton Prize for his work on the philosophical aspects of cosmology. He is a past President of the International Society on General Relativity and Gravitation, and of the International Society for Science and Religion. Ellis was an outspoken opponent of apartheid during the 1970s and 1980s, was awarded the Order of the Star of South Africa by Nelson Mandela, in 1999.