D. Lewis, Possible Worlds Theory - Modal Realism Study

The paper is mainly to study David Lewis' possible world theory- Modal Realism: the ontological doctrine that our world is but one of a plurality of worlds, and that we who inhabit this world are only a few out of all the inhabitants of all the worlds. The conception of "possible world" can be retraced to Leibniz .It is becoming more widely used after the birth of possible world semantics, but people do not share the same view on what possible world is. David Lewis thinks that possible world is the same kind as our world? I and my all surroundings". So it has the same ontology status as the actual world.This paper can be divided into four parts. The first part introduces the background of Modal Realism. Beginning by inspecting the root of Modal Realism, it illuminates the source of possible world theory and the application of modal semantics. The second part illustrates the basic viewpoints of Modal Realism. The third part expounds the objections and arguments to Modal Realism. In the fourth part, the paper shows that Modal Realism is actually a substitute frame, and it also explores what possible world means in our daily language.