What is nonclassical about interference phenomena?

In this talk I will first show how the phenomenology of quantum interference that is traditionally regarded as problematic does not pose a challenge to the classical worldview.

I will do so by describing an alternative to quantum theory, a statistical theory of a classical discrete field (the "toy field theory") that reproduces the relevant phenomenology of quantum interference while rejecting all the radical interpretational claims usually associated with it. Then, I will show what more nuanced aspects of the phenomenology of quantum interference actually state a departure from the classical worldview insofar as they constitute a proof of contextuality. More precisely, it is the functional form of the tradeoff between fringe visibility and which-path distinguishability that can witness nonclassicality.