From Shared Evidence to Group Attitudes

复杂、协调的工作，如组织国家情报、救援洪灾灾民或进行大规模科学研究，既需要汇集和共享信息。这两个过程既有联系又有区别。指挥官可以集中情报并能够定位目标，而现场特工则无法做到这一点。情报不被分享，或者对所有外地军官来说都不是公开的，这一事实甚至可能是行动成功的关键。那么，共享和共享信息之间的确切关系是什么呢？共享信息总是共享的吗？时间和资源有限的个人如何有效地共享和/或汇集他们拥有的信息？这些问题在哲学逻辑学中引起了极大的关注，但到目前为止，答案在很大程度上取决于理想化。这些模型中的代理是“逻辑上全知的”，即他们知道他们信息的所有逻辑后果。因此，在这些模型中，池只是一个将每个代理的所有信息放在一起的问题。但总体而言，从汇集中得出正确的结论可能根本不是微不足道的。标准的逻辑模型还假设，代理可以存储高度复杂的概念，例如“人人都知道……”的无限次迭代，这是所谓的“常识”定义的核心。这个项目将解除这些理想化，并为认知和推理能力有限的代理人分享和汇集研究。我们将为不具有经典模型完全演绎能力的代理开发共享信息的概念，例如公共知识，并将使用判断聚合和信念合并理论中的工具来为非理想代理开发新的信息池逻辑模型。最后，我们将研究小组中的信息动态，特别是问题和答案的辩证法，如何促进或阻止共享和共享。该项目将建立在现有的、相当成功的捷克-德国哲学逻辑学家团队的工作基础上。多年来，该团队一直在为资源有限的个人研究知识和信念的动态变化的合理模型。拟议中的研究重点是群体信息，这是自然的下一步。

Complex, coordinated efforts such as organizing national intelligence, rescuing flood victims, or conducting large-scale scientific research require both pooling and sharing information. These two processes are related but different. A commanding officer may pool intelligence and be able to locate a target while an agent in the field is unable to do so. The fact that the intelligence is not shared, or 'out in the open' for all field officers, might even be crucial to the success of the operation. What is, then, the precise relationship between pooling and sharing information? Is shared information always pooled? How can individuals with limited time and resources effectively share and/or pool the information they have? These questions have attracted a lot of attention in philosophical logic, but up to now the answers rest heavily on idealizations. Agents in these models are 'logically omniscient', i.e, they know all the logical consequences of their information. So in these models pooling is just a matter of putting together all the information of each agent. But in general reaching the right conclusions from pooling might not be trivial at all. Standard logical models also assume that the agents can store highly complicated notions, for instance an unbounded number of iterations of 'everybody knows that everybody knows that...', which are at the heart of the definition of so-called 'common knowledge.' This project will lift these idealizations and study sharing and pooling for agents with limited cognitive and inferential capacities. We will develop notions of shared information, e.g. common knowledge, for agents who do not have the full deductive power of classical models, and will use tools from the theory of judgment aggregation and belief merging to develop new logical models of information pooling for non-ideal agents. Finally, we will study how information dynamics in groups, and in particular the dialectics of questions and answers, can foster or prevent both pooling and sharing. The project will build on the work of an existing and rather successful Czech-German team of philosophical logicians. The team has been working on plausible models of the dynamics of knowledge and beliefs for resource-bounded individuals for some years now. The proposed research, focused on group information, is a natural next step.