              We may mainly pass over as uncontroversial the suggestion that there are efficient causes in favor of the most controversial and difficult of Aristotle four causes, the final  cause.[19]   We should note before doing so, however, that Aristotle’s commitment to efficient causation does receive a defense in Aristotle’s preferred terminology; he thus does more than many other philosophers who take it as given that causes of an efficient sort are operative. Partly by way of criticizing Plato’s theory of Forms, which he regards as inadequate because of its inability to account for change and generation, Aristotle observes that nothing potential can bring itself into actuality without the agency of an actually operative efficient cause. Since what is potential is always in potentiality relative to some range of actualities, and nothing becomes actual of its own accord—no pile of bricks, for instance, spontaneously organizes itself into a house or a wall—an actually operative agent is required for every instance of change.  This is the efficient cause. These sorts of considerations also incline Aristotle to speak of the priority of actuality over potentiality: potentialities are made actual by actualities, and indeed are always potentialities for some actuality or other.  The operation of some actuality upon some potentiality is an instance of efficient causation.