"A writer's ambition should be to trade a hundred contemporary readers for ten readers in ten years' time and for one reader in a hundred years' time"

Arthur Koestler's quote explores the long-lasting impact of literature and the aspirations of a writer to achieve timelessness in their work. The essence of this declaration lies in the understanding that real literary success is not measured by instant popularity or widespread modern readership, however rather by the lasting impact and significance of a writer's work over time.

Koestler recommends that an ambitious writer ought to choose to have less readers who deeply comprehend and appreciate their work over the long term, rather than a large audience in today. The concept of trading "a hundred contemporary readers for ten readers in 10 years' time" highlights the idea that immediate recognition may bring short lived satisfaction, however withstanding worth is recognized through regularly resonating with future generations. The emphasis on "10 readers in 10 years" indicates that quality and depth of engagement are more important than quantity. These ten readers are people who will take the time to explore, reflect on, and possibly be motivated by the writer's work, thereby perpetuating its worth gradually.

In addition, Koestler magnifies his point with the profound principle of composing for "one reader in a hundred years' time". This underscores a belief in the durability of art and literature-- the concept that creating work of considerable depth and authenticity can transcend its temporal context. Such work might potentially touch the intellect or soul of a reader far in the future, therefore approving the writer a kind of immortality through their words and ideas.

In essence, Koestler's quote is an admonition to authors to focus on creating work that seeks a much deeper connection and resonance, beyond the ephemeral patterns of their own era. It reflects an understanding of literature as a discussion across time, and an encouragement to craft works that engage exceptionally with the human condition so they remain engaging and informative for future generations.