In the following days, Tomas suddenly becomes aware that he is “sick with compassion,” and there is no heavier emotion than this. Tomas goes to the hospital and tells the director (the same man who had given him the job in the first place) that he must return to Prague. The director is understandably upset, but Tomas simply shrugs and says: “Es muss sein. Es muss sein.”
The “es muss sein” motif repeats throughout the book. The phrase literally translates to “it must be.” It is another example of eternal return and also represents the fate and predestination implied within eternal return. If everything has already happened before, then one is destined to make one decision or another—each event that occurs literally must be.
Tomas’s words are a reference to one of Beethoven’s quartets, the narrator says. The quartet is based on two motifs—Muss es sein? (Must it be?), Es muss sein! (It must be!), Es muss sein! (It must be!)—and is usually translated as “the difficult resolution.” With Tomas’s words, the doctor, a great lover of Beethoven, smiles. “Muss es sein?” he asks. “Ja, es muss sein!” Tomas answers.
The exchange between Tomas and the doctor again suggests that Tomas’s decision to return to Prague is fate—he simply must go and doesn’t really have a choice in the matter after all. While Tomas is now convinced that Tereza is his fate, he later convinces himself she is merely chance, or coincidence, and he deeply doubts the decision he makes here.