Very nice obituary at the

Very niceĀ obituary at the Guardian of David Lewis, the Princeton metaphysician famous (for a philosopher) for his stalwart defense of the existence of real, live alternative dimensions. On Lewis's theory, any state of affairs that is possible is actual on some world or other that differs from this one only in not being this one. So there is a possible world with David Lewis still on it (his Lewisian “counterpart” at any rate) and that world is richer philosophically than ours.

To learn a little about David Lewis's philosophy, try David King's discussion of a few Lewis quotes about possible worlds. What exactly is a possible world? Try the entry at xrefer.