Abstract Weber famously invoked ‘ideal types’ as an analytic device with which to measure empirical reality against some hyper-rational fabrication. Case in point: non-professional (lay) investors appear to be the antithesis of rational economic man. They have been cast as less-informed, less-skilled, and less-knowledgeable than professional market practitioners, and with ample evidence that they tend to lose money in the market as a result. This study builds the case that a new class of algorithmic financial advisor, commonly known as ‘roboadvisors’, enacts lay investors as rational market actors. This is achieved through algorithmic devotion to modern portfolio theory (MPT), which the roboadvisors embody, automate and perform, conjuring some version of homo economicus into existence. Through this example, I show how Weberian ideal types and the particular kind of rational action associated with them (e.g. the ideal type investor) become the very empirical reality they were intended to be a foil to – accomplished through the technological articulation of financial models, even in the hands of ordinary individuals.

中文翻译：

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扮演理性角色：Roboadvisors 和理想类型的算法性能

摘要 韦伯著名地将“理想类型”作为一种分析工具来衡量经验现实与某些超理性的捏造。举个例子：非专业（外行）投资者似乎是理性经济人的对立面。他们被认为比专业的市场从业者信息少、技能少、知识少，并且有充分的证据表明他们往往因此在市场上赔钱。这项研究建立了这样一个案例，即一类新的算法财务顾问，通常被称为“机器人顾问”，将非专业投资者制定为理性的市场参与者。这是通过算法对现代投资组合理论 (MPT) 的投入实现的，机器人顾问体现、自动化和执行，使某种版本的经济人得以存在。通过这个例子，