In September, the weather turns cooler and the leaves start to change. The war begins to turn against the Italian army and the Allies in general. Henry's recuperation from his injury is nearly complete, and he now has only three weeks left of convalescent leave before having to return to the front.
Henry and Catherine's relationship thrives in summer while he is injured. But injuries heal, and autumn and cold weather always return. These are the realities of life, and Henry must soon return to the front.
Henry notices that Catherine seems upset, and after a little pressuring he gets her to tell him what's wrong: she's three months pregnant. Catherine asks Henry if he feels trapped. He responds that you "always feel trapped biologically." This leads them close to a fight, but they both quickly back off and promise that nothing will come between them.
Catherine's pregnancy is another reminder of reality. It will make it impossible to hide their relationship and pit Henry's duty to Catherine against his military duty. They don't fight because they need their relationship to seem perfect, without conflict.
Henry comments that Catherine is too brave for anything bad to happen to them, though Catherine counters that even brave people die. Henry then quotes the famous saying, "The coward dies a thousand deaths, the brave but one." Catherine responds that whoever came up with that was probably a coward, and that the person who is both intelligent and brave dies two thousand deaths but doesn't mention them.
Catherine's comment about the "intelligent and brave" articulates the stoic philosophy that many of Hemingway's heroes share: suffer, but don't complain about it. Henry still seems to think that bravery will protect him from harm, but Catherine, who has experienced more loss, knows better.