In "Sometimes a Great Notion," Ken Kesey explores the themes of determination and the human experience, emphasizing the notion that individuals often grapple with uncertainty in life. The quote "Man is certain of nothing but his ability to fail" encapsulates the struggle between ambition and the reality of setbacks. It suggests that while people may pursue their dreams and goals, the inevitability of failure looms as a stark reality that everyone must confront.

This statement points to a broader observation about human nature; despite our efforts, we cannot always control the outcomes of our actions. Kesey's work reflects on the complexity of chasing success and the resilience required to navigate through failures. Ultimately, this perspective encourages readers to recognize that failure is a common part of existence, and it can serve as a vital learning experience in the larger journey of life.