Haavelmo’s Epistemology for an Inexact Science
解读哈维尔莫《概率方法》前两章的认识论框架，区分潜在影响与实际影响，指出被动观测难以获知潜在影响，对理解非实验条件下寻找经济规律有启发。
The first two chapters of Trygve Haavelmo’s Probability Approach provide a very rich epistemological framework for understanding what is involved in finding laws outside the laboratory. Even though these laws will be inexact, a framework was developed to specify for which conditions laws could be found. Therefore, Haavelmo defined two different kinds of influences, potential and factual influences. To decide whether a regression equation represents a law, it is not the strengths of the factual influences that are relevant, but whether the potential influences are significant. Unfortunately, by passive observations only it is difficult to obtain knowledge about potential influences, particularly when they have not revealed their strengths (yet).