[Revised entry by John D. Norton on November 24, 2022. Changes to: 1.svg, 2.svg, 3.svg, 4.svg, 5.svg, 6.svg, AP_Fig_1.svg, AP_Fig_2.svg, AP_Fig_3.svg, AP_Fig_4.svg, AP_Fig_5.svg, Gauge_1.svg, Gauge_2.svg] What is space? What is time? Do they exist independently of the things and processes in them? Or is their existence parasitic on these things and processes? Are they like a canvas onto which an artist paints; they exist whether or not the artist paints on them? Or are they akin to parenthood; there is no parenthood until there are parents and children? That is, is there no space and time until there are things with spatial properties and processes with temporal durations?...