DEFINITION: AGENCY
Agency is the capacity for human beings to identify opportunities and make choices that are consistent, correspondent, existentially possible, and coherent with and within reality, and to act upon them, unimpeded by knowledge limitation (ignorance), intellectual limitation(intelligence), mindfulness limitation (impulse), physical limitations(body), instrumental limitations(technologies), resource limitations, the impediments of others and their organizations into norms, laws, institutions, polities, and armies. Perfect agency would require omniscience, omnipotence, and complete insulation from impulse.
Simon Ström translates Agency to the language of physics:
AGENCY = POTENTIAL ENERGY
Agency = potential energy (PE)
Force = applied energy (F)
Event = Impulse (Imp), [force vector + temporal dimension]
Consequence = displacement vector (s)
Action = work (W)
Externalities = Waste heat (h)
W = F * s