 What about those extremely rare instances where there is absolutely no basis upon which to make probability estimates? Suppose you don’t even have a hunch regarding the greater likelihood of one alternative over another. According to orthodox Bayesian decision theory, the “principle of insufficient reason” then should be observed; it says that when there is no reason to assign a greater likelihood to one alternative rather than another, then an equal probability is to be assigned to each potential outcome. This makes sense on the assumption that if you have no more premonition of the likelihood of one option rather than another, they are for all you know equally likely to occur. By observing this rule of choice consistently over time, a rational chooser presumably should maximize his or her individual expected utility, and hopefully actual utility as well.