Among modern scholars of Islam, Mustafa Al-Zarqa has written that "Gharar is the sale of probable items whose existence or characteristics are not certain, due to the risky nature that makes the trade similar to gambling."[1] Sami al-Suwailem, has used Game Theory to try and reach a more exact, measurable definition of Gharar, defining it as "a zero-sum game with unequal payoffs".[9]