Modal realism: every possibility is real

Many believe that David Lewis had one of the finest minds of any modern philosopher. His concept of modal realism – the idea that infinite alternative worlds exist concretely in spacetime – was celebrated by his peers even while they doubted it, and his freewheeling style of writing demonstrated that it’s possible to be philosophically rigorous and still have fun. This week we explore the life and work of this pioneering American intellectual who had close ties with Australia.