The term
energy is used by writers and practitioners of various
esoteric forms of
spirituality and
alternative medicine to refer to a variety of phenomena. There is no
scientific evidence for the existence of such energy. Therapies that purport to use, modify, or manipulate unknown energies are thus among the most contentious of all complementary and alternative medicines. Claims related to energy therapies are most often
anecdotal, rather than being based on repeatable
empirical evidence.