新古典传统意义上的理性是给定选择对象与选择结果的概率分布,在精确计算基础上,个人追求最大化的行为方式。该理性长期内受到“有限理性”和“非理性”的批评与挑战。本文认为,在不确定情况下,人们追求最大化的任何选择都会受到选择范围、信息与知识的约束。因而精确计算后的结果与现实结果具有不一致性,约束越强,偏差就越大,理性是人们约束条件下追求最大化的行为。在给定的约束条件下,根据需求定律必然会产生特定的投资行为。 Neo-classical traditional sense of rationality is given the probability distribution of the object of choice and the choice of results, based on the precise calculation, the individual pursuit of maximized behavior. The reason is criticized and challenged by “bounded rationality” and “irrationality” in the long run. This paper argues that in the uncertain situation, any choice of people to pursue maximization will be constrained by the choice of scope, information and knowledge. As a result, the calculated result is inconsistent with the actual result. The stronger the constraint is, the larger the deviation is and the more rational the pursuit of maximization under the constraint of people. Given the constraints, according to the law of demand will inevitably produce a specific investment behavior.