  Decision theorists propose a normative theory of rational choice.
Traditionally, they assume that they should provide some constant and invariant
principles as criteria for rational decisions, and indirectly, for agents. They
seek a decision theory that invaribably works for all agents all the time. They
believe that a rational agent should follow a certain principle, perhaps the
principle of maximizing expected utility everywhere, all the time. As a result
of the given context, these principles are considered, in this sense,
context-independent.
  Furthermore, decision theorists usually assume that the relevant agents at
work are ideal agents, and they believe that non-ideal agents should follow
them so that their decisions qualify as rational. These principles are
universal rules. I will refer to this context-independent and universal
approach in traditional decision theory as Invariantism. This approach is,
implicitly or explicitly, adopted by theories which are proposed on the basis
of these two assumptions.
