  In the following we revisit the frequency interpretation of probability of
Richard von Mises, in order to bring the essential implicit notions in focus.
Following von Mises, we argue that probability can only be defined for events
that can be repeated in similar conditions, and that exhibit 'frequency
stabilization'. The central idea of the present article is that the mentioned
'conditions' should be well-defined and 'partitioned'. More precisely, we will
divide probabilistic systems into object, environment, and probing subsystem,
and show that such partitioning allows to solve a wide variety of classic
paradoxes of probability theory. As a corollary, we arrive at the surprising
conclusion that at least one central idea of the orthodox interpretation of
quantum mechanics is a direct consequence of the meaning of probability. More
precisely, the idea that the "observer influences the quantum system" is
obvious if one realizes that quantum systems are probabilistic systems; it
holds for all probabilistic systems, whether quantum or classical.
