Inter-world Individuals or Individuals limited to the World A Glance at Lewi's Counterpart Theory and Plantinga's Response to it

One of the questions in the context of possible worlds is whether an individual may exist in more than one world. Some scholars like David Lewis have denied the existence of an individual in more than one possible world while some others like Alvin Plantinga believe in inter world individuals. Raising Lewis´s approach concerning denial of inter world individuals, the present article explains the counterpart theory as the substitute one. Based on the counterpart theory, although each individual exists only in one possible world, he has counterparts in other worlds. In contrast, based on the theory of Plantinga, any individual may exist in more than one possible world. Therefore Plantinga´s words entail that an individual must have certain essential qualities leading to his distinction in each of the worlds. The last part of the article deals with the point that the issue of individual essence can refer to that of personification according to Muslim philosophers. Since personification, in its final analysis, does not refer to anything but existence, the hypothesis of individual essence resting on specification of universal by universal can not be accepted.