  "Ever since the advent of modern quantum mechanics in the late 1920's, the
idea has been prevalent that the classical laws of probability cease, in some
sense, to be valid in the new theory. [...] The primary object of this
presentation is to show that the thesis in question is entirely without
validity and is the product of a confused view of the laws of probability"
(Koopman, 1957). The secondary objects are: to show that quantum inferences are
cases of partially exchangeable statistical models with particular prior
constraints; to wonder about such constraints; and to plead for a dialogue
between quantum theory and the theory of exchangeable models.
