经济学应该如何处理“时间因素”——琼·罗宾逊的探索及其当代意义

经济学分析不能不处理时间因素对经济决策的影响这一重大问题。然而，经济学自诞生以来，在这个问题上的进展十分缓慢。现代主流经济学以自然时间或逻辑时间来定义“经济时间”，使用高度抽象的、形式化的、无差异度量方法，并据此建构越来越精致的分析模型。然而，经济学的解释和预测能力并未相应提高。从思想史角度对此问题进行考察，重点是研究20世纪杰出经济学家琼?罗宾逊关于历史的“经济时间”理论，我们可以看到，罗宾逊认为当经济学逐渐从静态分析走向动态分析时，对时间的处理应当采用历史时间的方式，即在经济分析中有过去、有未来以及有时间的单向前行。在经济分析中引入历史时间，不仅可以使经济分析过程更加贴近现实情境，也更有可能得到符合现实的结论。经济学家都应当重视时间因素，重视罗宾逊所强调的历史时间，从而构建和发展更加贴合现实的经济学。

How Should Economics Deal with ″Time″： Joan Robinson’sExploration and Its Contemporary Significance

Economic analysis has to deal with the major issue of the impact of time on economic activities. Since the birth of economics, the progress on this issue has been quite slow. Modern mainstream economics defines ″economic time″ in terms of natural time or logical time, using highly abstract, formalized, and indifference measurement methodology, and then constructing increasingly sophisticated analytical models on this basis. However, the explanatory and predictive ability of economics has not increased correspondingly. This paper examines this issue from the perspective of history of thought, focusing on the theory of historical ″economic time″ proposed by Mrs. Joan Robinson, an outstanding economist in the 20th century, and trying to explore its important ideological resources which have long been ignored by the academic circles. Using the methodology of comparative study of the history of thought, this article chose Introduction to Modern Economics, Mrs. Joan Robinson’s late representative work, as the main text material. Placing Mrs. Robinson’s theory of ″economic time″ in the historical course of economics since the formation of classical political economy, and comparing it with the American paradigm of economic analysis represented by Samuelson in the same period, this paper tries to accurately grasp its core connotations and characteristics, and clarifies its significance to the development of economics. This article sorts out Robinson’s connotation of historical time method as follows: (1) Unalterable Past. Economic analysis should be carried out in a particular and unchangeable context. Unless it started from a blank state, economic analysis involving time processes will have a certain historical background, even subject to a certain accumulation of experience. (2) Unidirectional Time. Firstly, only through a certain period of time, can most changes, morphological or quantitative in the economy, be realized. Secondly, in the dynamic process, the consequences and their concomitants will have impacts on the subsequent economic movements. These consequences and concomitants will accumulate and even interact with each other with the passage of time. (3) Unpredictable Future. In most instances, the future cannot be entirely known as it is no longer a simple superposition of the past or the present, but a new state. The future mainly involves both uncertainty and expectations in the analysis. Due to the lack of reliable information, uncertainty is not a probability that can be calculated, while expectation is the judgment which the economic subject makes on the basis of the existing information, and which carries its own subjective cognitive color and is not uniform. This article then chose the case of pricing primary products in Introduction to Modern Economics to specify how Mrs. Robinson introduced the paradigm of historical time in her analysis. Comparing it with Samuelson’s related statements in Economics (19th Edition), we find that Mrs. Robinson believed that even in the primary market which is extremely close to a fully competitive one, the price will not be the price at which supply and demand will be balanced, but more likely to be fluctuating. What is more, this fluctuation is not necessarily an equilibrium fluctuation. For Mrs. Robinson, the price is also ″a series of events″, and these events have their own temporal characteristics. It is different from Samuelson’s analysis. According to the analyses in her book and the methodology which she applied, this paper believes that Robinson is more eager to see an economic analysis method combining historical analysis with abstract theory.