One hears increasingly from philosophers that statistical inference is a technical study that is well in control by statisticians and should be left to them; and one hears, increasingly, from mathematical statisticians that all this talk about interpretations of probability is so much philosophical frosting that is utterly irrelevant to the serious business of producing mathematical statistics. "The more interpretations of probability there are, the wider the scope of applications of our purely mathematical theories." The point of this paper is (...) to present, in detail, a situation in which an individual with given degrees of belief, given evidence, and given values, will have three different and contrary courses of action recommended to him, each according to one of the three most popular interpretations of probability. (shrink)