Space is a major concept in metaphysics concerned with the structure within which physical objects and events are located and related to one another. Metaphysical inquiry asks whether space exists independently of the objects within it, whether it is primarily a system of relations among things, and how space connects with time, matter, motion, causation, and change. Questions about space also address whether spatial structure is an objective feature of reality or partly dependent upon the ways in which reality is perceived and described.