The key is to reflect on six kinds of capital goods: business capital, infrastructure, human capital, intellectual capital, natural capital, and social capital. All of these are productive, but each has a distinctive role.
关键是思考六种资本商品：商业资本、基础设施、人力资本、知识资本、自然资本和社会资本。所有这些资本都是生产性资本，但作用大不相同。