Is it possible for the vast mass of humanity to enjoy the living standards of today’s high-income countries? This is, arguably, the biggest question confronting humanity in the 21st century. It is today’s version of the doubts expressed by Thomas Malthus, two centuries ago, about the possibility of enduring rises in living standards. On the answer depends the destiny of our progeny. It will determine whether this will be a world of hope rather than despair and of peace rather than conflict.