The social world differs from the physical world because it is man-made and hence almost infinitely malleable. So, unlike the natural sciences, economics advances scientifically not by replacing old models with better ones, but by expanding its library of models, with each shedding light on a different social contingency.
社会世界与物理世界不同，因为它是人造的，因此有几乎无穷种可能。所以，与自然科学不同，经济学的科学进步不是来自用更好的模型取代就模型，而是扩大模型数量，每个模型让我们能够认识不同的社会现象。