ABSTRACT
Protagoras agreed to teach Euathlus law for a fee which was payable when the pupil won his first case. After the course Euathlus did not take part in any lawsuits, and the impatient Protagoras sued for his fee. He reasoned that, if he won, Euathlus would be obliged by the court to pay his fee; if he lost, Euathlus would have won a case and so be contractually bound to pay. Euathlus reasoned that if Protagoras won he would not be bound to pay, for he did not have to pay until he won a case; if Protagoras lost, the court would have decided he need not pay. Who is right?
