Esi sivakalisi silandelayo saziwa ngokuba yi-"drinks's paradox": "Kukho umntu ebharini, ngoko ke ukuba uyasela, wonke umntu okwibhari uyasela." Akukhathaliseki nokuba umntu omnye ukhuthaza abanye ukuba basele okanye nokuba kukho omnye umnyango ongasemva, njengoko siza kubona ngomzuzwana. Ngumzekelo omhle ovela kwingqiqo yesivisa semathematika.
Siqala ngokuchaza ukuba wonke umntu okwindawo yokuthengisa utywala uyasela okanye umntu omnye okwindawo yokuthengisa utywala akaseli. Umahluko wemeko elandelayo ke ngoko ufanelekile:
- Wonke umntu uyasela. Emva koko ukuba umntu usela ebharini, wonke umntu okwibhari uyasela - kuba wonke umntu uyasela.
- Umntu omnye ubuncinane akaseli. Kuwo nawuphi na umntu ongaseliyo, kunyanisiwe ukuba xa esela, wonke umntu osezivenkileni uyasela - ekubeni umntu akaseli ( \(A \Rightarrow B\) isoloko iyinyani xa \(A\) ibubuxoki).
Ngokusesikweni, kwisivisa esingenasizathu \(D\) kunye neseti engenanto \(P\) isivakalisi sinokumelwa ngolu hlobo lulandelayo.:
$$\exists x\in P.\ [D(x) \Rightarrow \forall y\in P.\ D(y)]$$