Active and middle voice inflection within several classes of change of state and stative events can be explained in terms of the semantic notions affected subject and reduced energy. These notions are incorporated within a cognitive model of voice and transitivity that views both active and middle voice constructions as basic and non-derived. Active and middle voice are the manifestations of opposite poles of an energy continuum whereby active voice reflects greater energy and middle voice less energy. In highly intransitive events, such as pure states, a more abstract analogue of a physical energy continuum can be manifested as emphasis versus lack of emphasis or presence of volition versus absence of volition. Middle inflected passive constructions are functionally rehted to middle inflected changes of state because of the low degree of agency represented in both. The difference between passive and middle constructions is therefore graded rather than absolute, since both typically represent agentless events.