David K. Lewis, 60; Philosopher Believed in ‘Possible Worlds’

David Kellogg Lewis, 60, a Princeton University philosopher once dubbed “a mad-dog modal realist” for believing any logical world one can think of actually exists, died of heart failure Oct. 14 at his home in Princeton, N.J.

The bearded and bespectacled Lewis was described in a review of his latest book by the Times Literary Supplement of London as “the leading metaphysician at the start of this century, head and beard above his contemporaries.” But many considered Lewis’ pronouncements pure nonsense.

In his 1973 book “Counterfactuals,” he espoused a theory on what he called “possible worlds,” prompting serious discussions about the reality of Conan the Barbarian, Middle Earth of “The Hobbit” and “Lord of the Rings” fame, and the planets explored in “Star Trek.”

Born in Oberlin, Ohio, Lewis studied at Swarthmore College, Oxford and Harvard universities and taught philosophy at UCLA before going to Princeton.