Some people believe in the existence of a non-material world in a sense beyond that of just mental experience. They rather believe in supernatural beings and in a supernatural reality absolutely different in kind to that of the natural world. If such a reality exists then clearly it is beyond the reach of science. On the other hand science has been very successful in bringing apparently inexplicable and supposedly supernatural phenomena within its scope.
The "natural world" is sometimes thought to exclude human as well as supernatural activity.
See also: materialism