Nick Bostrom is a philosopher at the University of Oxford, and known for his work on the anthropic principle. Bostrom was also the co-founder (with David Pearce) of the World Transhumanist Association; as of December 2003, he is the chair of that institution. In 2004, along with James Hughes, Bostrom co-founded the Institute for Ethics and Emerging Technologies.
See also: Doomsday argument, Simulation argument.