The intervention theory of the origin of terrestrial life is a group of alternative hypotheses of the origin of life on this planet. Intervention theories postulate that life was deliberately introduced to this planet by intelligent extraterrestrial beings - contrast this with panspermia theory, which hypotheses that simple life was introduced to Earth through unintelligent mechanisms. Intervention theories may be coupled to the operation of evolution (through natural selection or other mechanisms), or may be concerned only with the introduction of human life (see Lloyd Pye). Some intervention theories (generally those that postulate intervention after some life had developed) are fully testable hypotheses, and although philosophically interesting, have little supporting evidence. Philosophers sometimes draw attention to the existence of intervention theories and panspermia theory to dispel claims of a false dichotomy between creationism and evolution by some proponents of intelligent design.