  The Drinker Paradox is as follows.
  In every nonempty tavern, there is a person such that if that person is
drinking, then everyone in the tavern is drinking.
  Formally, \[
  \exists x \big(\varphi \rightarrow \forall y \varphi[x/y]\big) \ . \] Due to
its counterintuitive nature it is called a paradox, even though it actually is
a classical tautology. However, it is not minimally (or even
intuitionistically) provable. The same can be said of its dual, which is
(equivalent to) the well-known principle of \emph{independence of premise}, \[
  \varphi \rightarrow \exists x \psi
  \ \vdash \ \exists x (\varphi \rightarrow \psi) \] where $x$ is not free in
$\varphi$.
  In this paper we study the implications of adding these and other formula
schemata to minimal logic. We show first that these principles are independent
of the law of excluded middle and of each other, and second how these schemata
relate to other well-known principles, such as Markov's Principle of unbounded
search, providing proofs and semantic models where appropriate.
