Abstract

Experiments show that psi differs from known physical processes in a variety of ways, and these differences are described herein. Because of these, psi cannot be accounted for in terms of presently known physical laws. A number of theories, of which we review a sampling, suggest ways in which known physical laws might be expanded in order to account for psi. However, there is no agreement on which of these theories, if any, will ultimately provide a general explanation. A further problem in studying psi is that it is elusive, i.e., methods are not presently known by which it can be reliably produced. However, if psi is real, its study can open the door to a new frontier of knowledge and contribute to our understanding of consciousness.