Comparative Study of Physics Parallel Worlds and Possible Worlds of David Lewis

Abstract

At first glance, it seems that we can find similarities between the possible worlds proposed by Lewis and the theory of parallel worlds in physics. Both of these theories point to the possibility of the existence of worlds other than the one we live in. After Everett's theory, physicists’ attention was drawn to the notions of the multiverse and parallel universes. Parallel worlds are one of the theories that scientists and researchers in the field of physics are interested in. David Lewis, relying on physicalism and modal realism, is one of the supporters of the theory of possible worlds. In this paper, the foundations of the two theories are explained using the analytical-descriptive method, and then, using the comparative method, Lewis's possible worlds theory and parallel worlds are scrutinized. Both theories accept the existence of other worlds. Lewis's theory has six main features: 1- the existence and reality of possible worlds; 2- the absence of a causal relationship between possible worlds; 3- the similarity of possible worlds to our world and the difference in the content of possible worlds; 4- the impossibility of reducing possible worlds; 5- indexical reality; and 6- the space-time unity of branches in a world and incoherency in time-space relations among worlds. The results of this research show that if parallel universes are confirmed as a scientific fact, then the second, third, and sixth features of Lewis's theory may conflict with physical reality. If there is a contradiction due to the fundamental nature of these features, Lewis's theory of possible worlds will suffer a lot.

Keywords

• parallel worlds
• possible worlds
• quantum world
• temporal and spatial relations