Currently, individuals investigating 'subtle energy' promote three differing perspectives regarding its qualities and processes: (1) that these energies exist but do not affect organic life in any way; (2) that subtle energies are a "fifth force," distinctly different from the other four standard forces; or (3) that the variations and complexities of subtle energies manifest the four forces and elements that compose all force and matter. This last perspective, if proven true, would indicate that 'subtle energy' is a particular expression of space/time at the sub-quark level.
Despite the fact that orthodox science has attempted to empirically test for the existence of subtle energy (and found no statistically significant results) some complementary and alternative medicine (CAM) approaches not only assume its existence but believes that the purported subtle energy running through and surrounding the body can be manipulated so as to catalyze increased physical, psychological and spiritual health. Acupuncture along with other aspects of Traditional Chinese Medicine (TCM), Tibetan Buddhism, homeopathy, ayurveda and many other traditional medicine approaches worldwide serve as examples of this belief. Properly funded, conducted and repeated empirical research is necessary to determine if the success rate of these CAM approaches is due to 1) the existence of subtle energy, 2) the placebo effect, and/or 3) various other factors.
Resources: ENERGY MEDICINE: The Scientific Basis, by James L. Oschman, PhD, Churchill Livingston, 2000