Aumann's agreement theorem

About

Aumann's agreement theorem is an hypothesis first stated by mathematician Robert Aumann about the nature of rationality and decisionmaking which states that two people acting rationally (in a certain precise sense) and with full knowledge of each other's beliefs will accept each other's conclusions as following rationally from those beliefs.

It is not known to what extent this theory has been confirmed or how it may be applied to real-life situations.

Although more data is needed, it seems likely that the following statements are true:

There are obstacles (mostly bias) preventing humans from acting rationally in many situations.
Rigorous use of rationalist techniques makes it possible to overcome these obstacles for those who accept the need for such techniques.
Many people will not accept the need for rationalism; if they are to be persuaded of the conclusions arrived at by rational processes, more manipulative forms of argument will have to be used.
The ethics of such manipulation, even in situations where the target has rejected rationalism, have yet to be explored thoroughly.