How can we help humans thrive trillions of years from now? This philosopher has a plan

Let's say you're hiking, and you drop a piece of glass on the trail. Eventually someone will walk along the trail and might cut themselves on the glass.

You'd be really sorry to hear if it happens to someone you know in a week. But what if the victim lived thousands, even millions of years in the future?

Philosopher William MacAskill, 35, likes to bring up this scenario to drive home a point: "If you're thinking about the possibility of harming someone, [it doesn't] really matter that person will be harmed next week or next year, or even in a hundred or a thousand years. Harm is harm."

That's MacAskill's argument behind longtermism, a term he coined to describe the idea that humans have a moral responsibility to protect the future of humanity, prevent it from going extinct — and create a better future for many generations to come. He outlines this concept in his new book,.