Minkowski taught us that time is a coordinate axis, just like "X", "Y" and "Z". Coordinate axes do not "flow".
If one were born on a train (on an infinitely long and smooth track) and spent all his life there, and the train never stopped or slowed, by looking out of the window he would conclude that "X" (the coordinate axis X) flowed.
When Rudy Rucker (the mathematician and writer) met Kurt Gödel (a contemporary of Einstein and probably more intelligent), one of the questions he asked Gödel was: "What causes the illusion of the passage of time?"
Gödel answered obliquely, not directly addressing the question...but he did not say, "What kind of stupid ass question is that?!" In other words, he tacitly accepted Rucker's premise that the passage of time is an illusion...
--Boris