During my rush to express my general dislike of Chris Pratt I forgot to add some important information about time travel. While the initial sloppy premise of The Tomorrow War was for the world of 2051 to ask for help from our present day world the question of changing future events was always in the background.
Speaking strictly as a curious layman when it comes to the actual implications of traveling backwards in time I believe the scientific consensus is that it isn't possible. We are naturally traveling into the future one second per second and through various means like approaching the speed of light or sitting close to the edge of a black hole “faster” forward time travel is possible.
But every reasonable science article I have read or video I watch says traveling backwards in time is problematic. Without getting deep into the mathematical weeds, which I have no ability to comprehend, I think Einstein's theories say nothing prohibits backwards time travel as far as the universe is concerned but it would take God-like powers.
The key here is that nothing outright forbids backwards time travel so various real and respected scientists have speculated on what would happen if someone or groups began shuffling through the space-time continuum.
Of course the Grandfather Paradox is the favorite with some psychotic moron going back in time to kill his grandfather before his own father was conceived. So if the father was never born how could an insane kid go back and kill his grandfather?
Some have speculated that such actions would create a temporal loop. The kid is born as he is supposed to be, grows up and builds a time machine, then goes back in time shoots his teenage grandfather in the head. Granddaddy never has a son so the kid is never born. Because the kid is never born he never builds a time machine to go back and kill his grandfather. So events proceed as they occurred with the Grandfather having a son who goes one to have a kid of his own. So once again the kid grows up, hates his Grandfather, builds a time machine and travels back to shoot him in the head. This loop presumably would continue for eternity.
Is it just me or does this put a big dent into the idea of free will?
The alternative is that instead of a temporal loop, time has a way to protect itself. Instead of backwards time travel such a homicidal grand kid would instead travel to an alternate universe set in the years during his grandfather's childhood. Killing that person would prevent your counterpart from being born but leave your own universe/timeline untouched.
Going for shits and giggles here by throwing a hypothetical timey-wimey wrench into the time-space continuum, but what would be really wild is if we could reverse time would be to look at events on a much wider perspective. Instead of focusing our attention just on an insane genius-level kid traveling to the past to murder his teenage grandfather, look at the mundane decisions normal people make during the course of their day during that same period.
Insane kid keeps a record of what his friends, Tom, Dick, and Harry did the day before he pops back years in the past to kill his grandfather. Insane kid then goes forward in time to that day and secretly observes his friends to see if they make the same choices. These choices could be anything from what shirt they wear, the route they take to work, or what they decide to have for lunch.
If there is the least little bit of deviation from what they originally did that would leave open the idea of free will, I guess.
This all feeds back into the ultimate conclusion of the movie. While sending troops to the future to fight a clearly lost war just doesn't make any sense. The world of 2051 could have just sent the same group to our present with tons of information on what will happen along with the bio-weapon to make a more plausible movie.
Personally, while I have my doubts on the degree of free will humans actually have, I think the far more likely reality of backwards time travel would be sliding over to an alternate universe. But then again I'm no scientist, but goofing with the flow of temporal events just doesn't ring true in an universe that seems so highly ordered.