Serious answer Show him how climate change is real . What evidence do you think would change his mind ? Anytime I try to persuade someone who believes climate change is a hoax , they just tell me the real data actually shows the the earth is cooling , that climate change activists have been caught deliberately manipulating the data to support their claims , and that liberal media blah blah blah . <| sep |> a priori meaning theorized rather than observed . They need to find more terrestrial examples of biological and abiological deposits of this stuff to confirm the model . That will be cheaper , better science than just flying to Mars and back because it ' s fun . <| sep |> The end of the movie We Were Soldiers caused both my father and I to bubble like little kids . For me , it brought home the preposterousness of war , and just how much of a waste of human life it is . Great movie .