FROM DEAN RADIN, SENIOR SCIENTIST AT THE INSTITUTE OF NOETIC SCIENCES: If by "nonphysical" one means the inner world of personal, subjective experience, then yes, extrasensory perception reveals something about the subjective. But then, that’s the purpose of most conventional psychological experiments, to say nothing of psychotherapy. So presumably we’re not talking about that type of nonphysical.
If by "nonphysical" one means aspects of reality that are neither material nor energetic, and if one is also a “physicalist,” which many scientists imagine themselves to be, then no, ESP cannot reveal anything about the nonphysical because from that framework, there is nothing other than physical.
If by "nonphysical" one means wholly beyond the natural world, or supernatural, then again the answer is no. ESP experiences happen repeatedly, in every culture and at every level of educational achievement. So they are perfectly natural. It’s only their interpretation that is considered controversial. In any case, as science marches on, more and more of what used to be called supernatural, paranormal, or magical inevitably become ho-hum normal. So ESP reveals nothing of interest here.
If by "nonphysical" one means an aspect of reality that is neither material nor energetic but rather informational, then yes, ESP does reveal something. It may seem odd to imagine that there is an informational reality that is not physical, but that’s what logic, relationships, and even the essence of language are all about. There are ways that both the material and energetic worlds are modulated into meaningful patterns, where the pattern alone is the thing of interest, and not the physical medium. If someone whispers “you’ve won the lottery” in your ear, the modulation of the physical world is minuscule. But the meaning conveyed by that informational pattern, and the resulting energetic release, can be enormous. More pertinent to what ESP may be revealing, there are also meaningful correlations that have no known physical carrier or substance at all, such as the space-and-time-transcending correlations known as quantum entanglement.
ESP may be thought of as a means by which information flows between humans, and between humans and the environment, without the use of the known physical forces. In this sense, ESP reveals the nonphysical. Exactly how this all happens is not yet certain, but that it does happen is increasingly supported by empirical evidence collected in controlled laboratory tests, and by an intriguing similarity to the nonlocal nature of reality revealed by quantum mechanics.

Dean Radin appears with Marilyn Schlitz, Charles Tart, Susan Blackmore, Rupert Sheldrake, and Michael Shermer in "Does ESP Reveal the Nonphysical?" the 11th episode in the Closer to Truth: Cosmos, Consciousness, God TV series, hosted and created by Robert Lawrence Kuhn. The series airs Thursdays on the PBS HD network and many other PBS stations. Every Friday, participants will share their views on the previous day's episode.