paper ([Neumaier]{} [@Neu1]), a proposal for such a realistic interpretation will be presented.

Feynman’s argument {#feynman}
==================

In his 1948 paper “Space-time approach to non-relativistic quantum mechanics” [@Fey], Richard [Feynman]{} gives on pp.368-369 the following argument.

[*“We define $P_{ab}$ as the probability that if the measurement $A$ gave the result $a$, then measurement $B$ will give the result $b$. \[...\] denote by $P_{abc}$ the probability \[...\] if $A$ gives $a$, then $B$ gives $b$, and $C$ gives $c$. \[...\] If the events between $a$ and $b$ are independent of those between $b$ and $c$, then P\_[abc]{}=P\_[ab]{}P\_[bc]{}. This is true according to quantum mechanics when the statement that $B$ is $b$ is a complete specification of the state. In any event, we expect the relation P\_[ac]{}=\_b P\_[abc]{}. Now, the essential difference between classical and quantum physics lies in Eq. . In classical mechanics it is always true. In quantum mechanics it is often false. \[...\] The classical law, obtained by combining and , P\_[ac]{}=\_b P\_[ab]{}P\_[bc]{} is replaced by \_[ac]{}=\_b \_[ab]{}\_[bc]{}. If is correct, ordinarily is incorrect. \[...\] Looking at probability from a frequency point of view simply results from the statement that in each experiment giving $a$ and $c$, $B$ had 