Reason to believe

We are confronted with new information all the time. The information we face and on which our beliefs are based is often chaotic, disordered, and even contradictory. Yet at the same time, our belief is expected to be consistent. Is it possible for us to achieve and maintain consistency in our beliefs? How do we manage to extract consistent belief from inconsistent information? We attempt to answer these questions from a logician's perspective, borrowing ideas and techniques from other fields, for example, topology, formal argumentation theory, non-monotonic reasoning and Markov chain theory.
The dissertation is structured around two topics -- single-agent belief and group belief. For both a single agent and a group of agents, we take belief formation as a process of resolving the inconsistency in its basis. The difference is that in the case of a single agent, evidence is taken as the basis of her belief and in the case of a group of agents, each group member's belief is taken as the basis of the group's belief.
Throughout the whole dissertation, the recurrent theme is a tension between believing more and believing more consistently. We demonstrate that in the case of a single agent, it is possible to strike a balance in a meaningful way. For group belief, nonetheless, besides its amount of content and consistency, we also need to consider whether the aggregation of the group members' beliefs is democratic enough. Our proposals exemplify possible ways of relieving this tension.