Once education, reason and experience convince many of us to abandon the simplistic beliefs of organized religions, we often retain a fascination with the supernatural. In particular, we imagine that a spiritual plane exists (undetectable with our human senses) that will rescue us from the prospect of utter annihilation following death.
This vague hope, which has no basis in science, is exploited by self-proclaimed psychics and mediums who, for a fee, offer access to that spiritual realm. Such enticements, comparable to the promises of organized religions, provide reassurance that life extends beyond the grave and that we will be able to reconnect with loved ones in the hereafter.
Acceptance of the supernatural is fueled by the realization that science is unable to explain everything that occurs (or has occurred) within the known Universe; of course, this point has been used to support religious beliefs as well. Indeed, the unknown is a powerful source of hope and, though science has solved many mysteries throughout human history, the drive for self preservation (inherent in our genes), combined with our capacity for imagination, feed the conviction that we humans (and perhaps all life forms) possess spiritual traits that are beyond the detection of modern science. Therein lies the foundation for supernatural beliefs: the conviction that life is both physical and spiritual; in other words, life has an immortal component. Naturalists, myself included, are inclined to believe that supernatural phenomena, as well as our fervent hope that they exist, are products of the complex human brain.