We can see this concretely in the development and declining costs of new medicines like HIV drugs, and in the creation of new seeds that allow poor farmers to be more productive. Once such tools are invented, they are never un-invented – they just improve.
西雅图&mdash;过去十五年来，世界最穷人群的生活的改善比以往任何时候都要快，但我乐观地认为，未来十五年会变得更好。毕竟，人类知识在进步。这具体表现在HIV药物等药品的研发和成本下降，以及让贫穷农民收获更多产量的新种子的创造上。一旦这样的新工具被发明出来，就不会倒退回去&mdash;&mdash;只可能进步，不可能退步。