Folk-psychological considerations Folk psychology provides the framework within which we think about decisions. According to this framework, decisions are intentions to act based on reasons. To act rationally, then, means to act with adequate reasons. Expectation refers to the belief how likely it is that an option has a particular feature or leads to a particular outcome. Expectation is typically measured in probabilities.
Value refers to the strength of the desire for an option's feature or outcome.
Measuring value is even more difficult than measuring expectation.