In the 20th century, economics lost its purpose and started chasing the false goal of GDP growth. In recent decades, that has pushed many societies into deepening inequality and it's pushing us all towards ecological collapse. This century calls for a new goal, meeting the needs of all within the means of the planet. In other words, it's time to get into the doughnut, the sweet spot for humanity. But that's no easy task. Today, billions of people still fall short of their daily needs, from food, housing and energy to healthcare and education. And yet collectively, we've already overshot our pressure on some of Earth's most critical life support systems, driving climate change and the breakdown of biodiversity. What we do to this Earth in the next 50 years will shape the next 10,000. So let's replace that last century goal of endless growth with the goal of thriving in balance. And if we have half a chance of getting there, what economic mindset would be fit for the task?