Artificial Intelligence has a foundational paradigm of agents: these agents exhibit "intelligence". An agent perceives the environment through its sensors; processes the input and performs an intelligent action through its actuators. One example that would illustrate this could be of humans. We perceive the environment through our sensors, i.e. our organs (eyes, ears, nose etc.) and we think about the inputs we've just received, decide on a course of action and act on it using our actuators, i.e. our hands, legs and/or others. In some cases, instantaneous/reflex actions are needed: in case one's hand is in fire, the best possible action would be the reflex action of pulling your arm out of the fire without thinking about it.