Abstract：A key question in (social) epistemology is whether a group can have belief and knowledge as an individual agent does. Moreover, how should we understand the belief and knowledge of a group if it can have them; what are the relations and differences between a group's belief and an individual agent's belief? To answer these questions, several different theories have been proposed. They can be roughly divided into two categories： summativism and non-summativism. According to summativism, group belief can be completely reduced to each individual group member's belief and a group cannot have belief as an individual agent does. According to non-summativism, a group has its own agency so its belief is not a simple aggregation of its members' beliefs. The division between these two categories seems to implicitly assume that a group's agency necessarily follows from the irreducibility of its belief to individual agents' beliefs. In this paper, we propose a new theory of collective belief — potential group belief, which cannot be classified into the two categories. Our theory also demonstrates that the above assumption does not necessarily hold. According to our theory of potential group belief, a group's belief can be taken as the group members' tendency towards consensus which is enforced by the social influence on a social network. So potential group beliefs cannot be reduced to individual agents' beliefs. The core of our theory is that the tendency to consensus has resulted from the social interaction between the group members.. Moreover, there is no need to assume group agency in our theory. We take a group as a dynamical system whose belief thus serves as a description of the status of the system. By taking social influence on a social network into account, we analyze how structural properties of social networks can take effect in the formation of potential group belief. Our analysis shows that two properties of a social network can guarantee the formation of the potential group belief,namely, strong connectedness and aperiodicity. Strong connectedness requires any two nodes in a network to be connected by a path, namely a sequence of edges. In a strongly connected network, one reflexive node can ensure the network is aperiodic. In addition, we show that potential group belief as a modal operator satisfies almost all axioms and inference rules in the K axiom system except for the principle of closure under conjunction. This ensures the mutual consistency of potential group belief. To better illustrate the theory of potential group belief, we compare it with three theories of group belief in the literature, i.e. aggregate belief, common belief and corporate belief. While all these three theories can be classified as either summativism or non-summativism, the theory of potential group belief cannot. Compared to aggregated belief, potential group belief is not simply the aggregation of individual agents' beliefs. Compared to common belief, it does not require higher-order belief in other group members' beliefs. Compared to corporate belief, it allows the modelling of groups other than organizations and does not have any requirement of group agency. All results demonstrated in the paper have been achieved by formalizing potential group belief in a mathematical framework and logical system with rigorous mathematical proofs. We chose to leave out the technical content and focus on elucidating the intuitive idea and revealing the relevant philosophical issues behind the mathematical analysis. In summary, the theory of potential group belief takes a social group as a dynamical system and highlights the role of the social network in determining the status of the system. It provides a new perspective on the problem of how to understand collective belief by integrating philosophical issues, concepts from social science and methods from mathematics and logic.
引用本文:
石辰威. 潜在的集体信念[J]. 浙江大学学报(人文社会科学版), 2020, 6(5): 50-.
Shi Chenwei. Potential Group Belief. JOURNAL OF ZHEJIANG UNIVERSITY, 2020, 6(5): 50-.
