Elementary statistics provides us with a simple and generally accepted answer to the question which element of a statistical model for the interconnection between a dependent variable and a number of independent variables should be viewed as the optimal one. Such a statistical model M is, basically, a disjunction of mutually exclusive hypotheses each of which gives a probability distribution for the value of the dependent variable when the values of the independent variables are known, and the standard procedure for choosing from these hypotheses the optimal one is to choose the hypothesis which has the maximal likelihood relative to the existing evidence. The question how the statistical model itself should be chosen is much more controversial, however. Statisticians have proposed a variety of model selection criteria for making choices between such models, but there is no general agreement concerning the question which of these should be used.