Fridge Brilliance: Some have questioned how future humans could have created the tesseract which permitted Cooper to speak to Murphy if humanity was a generation away from extinction. When Cooper and TARS sacrificed themselves to get the Endurance away from the black hole, they saved the human race - Brand was able to set up the colony using Plan B; frozen embryos, exowombs, etc. A couple of aeons from now, future humans realize that Cooper was in a unique position to create the key elements of their society fast enough to save an entire planet worth of humans, and decide to help him. Humanity had no future until Cooper decided to sacrifice himself to save it, and in doing so, turn he himself was saved. Kind of like The Apotheosis of Martin Padway.
Or just a stable-time-loop-within-a-stable-time-loop.
It could be argued that helping Cooper save the people of Earth was simply how these Downstreamers' history went (yes we're calling them that). It wasn't any act of kindness or selflessness, but simply them setting in motion the events that led to their own existence.
This seems to just be the plot of the film, not Fridge Brilliance.
Removed:
Fridge Brilliance: Some have questioned how future humans could have created the tesseract which permitted Cooper to speak to Murphy if humanity was a generation away from extinction. When Cooper and TARS sacrificed themselves to get the Endurance away from the black hole, they saved the human race - Brand was able to set up the colony using Plan B; frozen embryos, exowombs, etc. A couple of aeons from now, future humans realize that Cooper was in a unique position to create the key elements of their society fast enough to save an entire planet worth of humans, and decide to help him. Humanity had no future until Cooper decided to sacrifice himself to save it, and in doing so, turn he himself was saved. Kind of like The Apotheosis of Martin Padway.
This seems to just be the plot of the film, not Fridge Brilliance.