The purpose of this paper is to highlight the central role that the time
asymmetry of stability plays in feedback control. We show that this provides a
new perspective on the use of doubly-infinite or semi-infinite time axes for
signal spaces in control theory. We then focus on the implication of this time
asymmetry in modeling uncertainty, regulation and robust control. We point out
that modeling uncertainty and the ease of control depend critically on the
direction of time. We also discuss the relationship of this control-based
time-arrow with the well known arrows of time in physics.Comment: 21 pages, 1 figur