In the essay "Symptoms," John Steinbeck discusses the effects that war can have on soldiers. He argues that soldiers often try to forget their experiences as a defense mechanism.
Steinbeck elaborates on this by comparing it to childbirth. He tells us that women similarly have the ability to forget about a traumatic experience because this enables them to have more children. It is a defense mechanism. Similarly, soldiers are able to forget the hardship of war in order to keep living their lives or to fight in a war again.
Steinbeck's purpose was to explain the experiences of war in a way that was more relatable to the reader. He is successful in doing so because he compares it to a phenomenon most readers are likely to be familiar with.