4. Polarization through discussion

Discussions within groups usually lead to polarization of opinions. This has been demonstrated by hundreds of studies and is formally called “group polarization”9,10. If someone approaches a discussion with two hypotheses that he gives about equal probability, he is likely to polarize in a direction opposite to that of an opponent. One facet of this is that many people have some tendency to argue for fun, or just for the sake of arguing. As enjoyable as this may be, in practice it narrows our representation of possible futures. Bayesian rationalists, who are trying to build the most realistic possible model of the future, should approach discussions with truthseeking in mind and be wary of arbitrary polarization, such as that caused by group polarization or otherwise. In fact, true Bayesian rationalists with common priors cannot agree to disagree on matters of fact, and must converge towards consensus on probability estimates11.