The quote emphasizes the unique nature of each day, suggesting that while knowledge and experiences from one day can inform and guide the next, the future cannot learn from the past in the same way. This reflects the idea that each day is an independent entity, endlessly moving forward. Each day's lessons are valuable, but they exist in isolation, unable to instruct the subsequent day.

In "Old Men at Midnight" by Chaim Potok, this theme resonates throughout the narrative, highlighting the complexities of life and the importance of personal experience. The book explores deep philosophical and existential questions, illustrating how the essence of each day contributes to our personal growth while also reminding us of the fleeting, transient nature of time.