Arthur W Brian
Santa Fe Institute, Santa Fe, NM USA.
Intelligent Systems Lab, PARC, Palo Alto, CA USA.
Nat Rev Phys. 2021;3(2):136-145. doi: 10.1038/s42254-020-00273-3. Epub 2021 Jan 29.
Conventional, neoclassical economics assumes perfectly rational agents (firms, consumers, investors) who face well-defined problems and arrive at optimal behaviour consistent with - in equilibrium with - the overall outcome caused by this behaviour. This rational, equilibrium system produces an elegant economics, but is restrictive and often unrealistic. Complexity economics relaxes these assumptions. It assumes that agents differ, that they have imperfect information about other agents and must, therefore, try to make sense of the situation they face. Agents explore, react and constantly change their actions and strategies in response to the outcome they mutually create. The resulting outcome may not be in equilibrium and may display patterns and emergent phenomena not visible to equilibrium analysis. The economy becomes something not given and existing but constantly forming from a developing set of actions, strategies and beliefs - something not mechanistic, static, timeless and perfect but organic, always creating itself, alive and full of messy vitality.
传统的新古典经济学假定经济主体(企业、消费者、投资者)完全理性,他们面对明确界定的问题,并采取与这种行为所导致的整体结果相一致的最优行为——处于均衡状态。这种理性的均衡体系产生了一种优雅的经济学,但具有局限性且往往不现实。复杂经济学放宽了这些假设。它假定经济主体各不相同,他们对其他经济主体的信息掌握不完美,因此必须尝试理解他们所面临的情况。经济主体进行探索、做出反应,并根据他们共同创造的结果不断改变自己的行动和策略。最终的结果可能并不处于均衡状态,可能展现出均衡分析中不可见的模式和涌现现象。经济不再是既定的、现存的,而是由一系列不断发展的行动、策略和信念持续形成的——它不是机械的、静态的、永恒的和完美的,而是有机的,始终在自我创造,充满活力且纷繁复杂。