What about the time travel paradoxes?
There aren't any. I don't know how many possible futures you have, and possible pasts we have. The possibilities surrounding the next time you put something on top of your refrigerator, must be at least infinite to a high power. You are going to move a particular piece of dust somewhere between 1.00000000000 milimeter and 1.00010000000 milimeter to the North. That's an infinite number of possible positions of that speck of dust, and possible pasts for us since for us they are indistinguishable from each other. You will eventually dust or vacuum up there, adding chaos into the outcome, and make it actually impossible to calculate the a priori state with anything like precision. Multiply that by all the possible positions for all the pieces of dust up there. . .
Hold it. Forget that. I think that shouldn't be here. I think that's from the proof that the physical world is not a computer simulation.
Anyway, just as you can only eventually reach your possible futures, we can only send messages back to our possible pasts. The fact that you are reading this is proof that reading it will not cause you to do anything that makes any distinguishable difference to our past.
At least that's one popular theory.
Meanwhile, everyone entirely agrees, you can change our future.