 Before turning to further elements of Leftow’s view, it is useful to pause to describe some background on the metaphysics of time (see also the SEP entries on  time,  John M.E. McTaggart, and  being and becoming in modern physics).  McTaggart distinguished between the A-series and the B-series of events. The A-series runs from the future through the present and into the past, while the B-series runs from earlier to later (McTaggart 1908). This distinction survives in the form of the contemporary opposition between the B-theory and (various versions of) the A-theory of time.