Modal Realism of David LewisDavid Lewis considered modal realism the heart of the world.
His six central doctrines touch the question of possible worlds, though some of the doctrines aren’t explicit and aren’t easily formulated. However, Lewis’s statements are the following:
- Lewis claims that possible worlds exist and they are as real as our world
- Lewis asserts that those possible worlds are “the same sort of things as our world” meaning that they may be different in content, though not in kind
- Lewis states that it is not possible to reduce the possible worlds to something more basic meaning that possible world are irreducible and have their own rights
- Lewis assumes that worlds are “actual” only in the sense that people leave, though possible worlds are indexical
- According to Lewis possible worlds are isolated from one another, though their parts are interrelated spatiotemporally
- Lewis emphasizes that isolation of the world is only casual (Lewis 1969)The first three doctrines suggest that people are only the parts of the actual world and they can’t assert that the world “has a special property not found in (or instantiated by) any other world”.
(Lewis 1969) Therefore, Lewis raise the question of world’s actuality and thus he thinks that people can’t use this term to indicate their position. The last three doctrines are the central to Lewis’ approach, because they are the foundation of any theory which having relation to realism. Despite the fact that the last doctrines are more difficult to draw out, it is apparent that they aim at finding principle of demarcation between possible worlds as well as at analyzing causation. It is possible to conclude that world isn’t simply a “set of possible individuals” and it isn’t of humans’ making.
Lewis assumes that people aren’t allowed to stipulate here as well as to use “some principle of compossibility if they want to use possible worlds to help us explain modal concepts”. (Lewis 1969)ReferencesLewis, David. (1969).
