In "Travels with Charley: In Search of America," John Steinbeck reflects on how humanity has historically been compelled to adapt due to external challenges such as weather, disasters, and diseases. These forces have often driven change in society, prompting people to alter their lifestyles and resilience. Steinbeck highlights that these adaptive shifts were often reluctant responses to unavoidable circumstances.

However, he suggests that the current impetus for change arises from within, stemming from our own biological successes as a species. Steinbeck points out that while we have triumphed over various external threats, our greatest challenge now lies in managing the complexities of our own existence and behaviors, emphasizing the need for self-awareness and responsible progress.