When Jonas Salk developed the polio vaccine, he refused to patent it--forgoing profit so that more lives could be saved. His radical generosity to future generations should inspire us, but leading philosopher Roman Krznaric sees the opposite happening: Our short-term, exploitative mindsets have "colonized the future," leaving an inexcusable chasm between the haves and have-nots--and mounting existential threats--that have brought our species to the...