Followup to my lower bound light speed question. I was told on the Sandbox to split the lower and upper bound for light speed in different Questions. Yes they are similar but it is possible that different formulas bind the light speed to a low bound than to an upper bound.
I am investigating the possibility of modifying the speed of light in my world. Assuming that the speed of light in a vacuum can (and in my world, is) modified, what upper bound exists that would permit humanity to exist?
I want to know how high light speed could get while still allowing for humans to live.