 This idea was adopted by Richard Arthur (1982, 107): “It is … proper time which is understood to measure the rate of becoming for the possible process following this timelike line (or worldline).” Arthur (2019) is an extended development of this view. The idea was also adopted by Dennis Dieks (1988, 456): “Only time along worldlines (proper time) has an immediate and absolute significance as an ordering parameter of physical processes.”