A common theory researchers attributed to psi mediation involved some undiscovered or unrecognized form of physical energy assumed to radiate from the individual as a field effect.
The energy was assumed to exist as small energy packets or quanta, so small that they were assumed to not interact with matter, whereby allowing the energy to pass though solid matter without difficulty.
Interests in such a “bio-energy” lead to the type of research commonly called psychotronics. The momentum of energy raised arguments targeting the theory, as energy tends to pass through matter unimpeded, therefore how could the energy be rendered inert as to be detected by the brain in cases of receptive psi?
The response to this argument was based on the supposition that the energy was not rendered inert, but rather effected via an interaction with neurological processes as the energy passed through the brain, correspondingly to how magnetic fields can induce electrical flow.
Unfortunately, even after years of psychotronic research, such a form of energy with these characteristics has not been found to exist. Because the energy field has not been found to exist,it cannot be subjected to empirical testing.
Therefore, this “theory” in terms of legitimacy is better categorized as a hypothesis. However, future quantum mechanical models of psi may lead to the discovery of this “bio-energy.” Current candidates include biophotons, which appear capable of quantum information transference.