It is not merely mechanically that we possess Space and are its centre; it is because we are living. Space is our life; our life creates Space; our body expresses it. To arrive at that supreme conviction, we have had to walk and to gesticulate, to bend and to straighten up, to lie down and to rise again. In order to move from one point to another, we exerted an effort - however small - corresponding to the beatings of our heart. Those heart beats proportioned to our gestures. In Space? No. In Time. In order to proportion Space, our body needs Time! The time duration of our movements, consequently, has determined their extent in space. Our life creates space and time, one through the other. Our living body is the expression of Space during Time, and of Time in Space. Empty and boundless Space - wherein we are placed at the start so that we may effect this essential transformation - no longer exists. We alone exist.
Adolph Appia, "Organic Unity" [trans. H.D. Albright, from Theatre in Theory: 1900-2000, ed. Krasner]