This is the first story in Future Imperfect, a 2001 anthology of 12 original time-travel stories, co-edited by the prolific anthologist Martin H. Greenberg (1941-2011) who was also a political science professor at the University of Wisconsin, Green Bay.
I recognized the theory—it’s the one on which time travel is based, even though we’ve never discovered time travel, at least not in any useful way, and researchers all over the universe discourage experimentation in it. They prefer the other theory of time travel, the one that says time is not linear, that we only perceive it as linear, and to actually time travel would be to alter the human brain.
But what Squishy is telling me is that it’s possible to time travel, it’s possible to open small windows in other dimensions, and bend them to our will.