  Individual choices often depend on the order in which the decisions are made.
In this paper, we expose a general theory of measurable systems (an example of
which is an individual's preferences) allowing for incompatible (non-commuting)
measurements. The basic concepts are illustrated in an example of non-classical
rational choice. We conclude with a discussion of some of the basic properties
of non-classical systems in the context of social sciences. In particular, we
argue that the distinctive feature of non-classical systems translates into a
formulation of bounded rationality.
