  Within quantum theory, we can create superpositions of different causal
orders of events, and observe interference between them. This raises the
question of whether quantum theory can produce results that would be impossible
to replicate with any classical causal model, thereby violating a causal
inequality. This would be a temporal analogue of Bell inequality violation,
which proves that no local hidden variable model can replicate quantum results.
However, unlike the case of non-locality, we show that quantum experiments
\emph{can} be simulated by a classical causal model, and therefore cannot
violate a causal inequality.
