When Bertlmann Wears No Socks. Common Causes Induced by Measurements as an Explanation for Quantum Correlations

It is well known that correlations produced by common causes in the past cannot violate Bell’s inequalities. This was emphasized by Bell in his celebrated example of Bertlmann’s socks. However, if common causes are induced by the very measurement process i.e., actualized at each run of a joint measurement, in a way that depends on the type of joint measurement that is being executed (hence, the common causes are contextually actualized), the resulting correlations are able to violate Bell’s inequalities, thus providing a simple and general explanation for the origin of quantum correlations. We illustrate this mechanism by revisiting Bertlmann’s socks example. In doing so, we also emphasize that Bell’s inequalities, in their essence, are about demarcating ʼnon-induced by measurements’ (non-contextual) from ‘induced by measurements’ (contextual) common causes, where the latter would operate at a non-spatial level of our physical reality, when the jointly measured entangled entities are microscopic in nature.