David Rakoff On Jon Stewart: Found A Tumor While Writing A Book About Pessimism And Melancholy (VIDEO)

Jon Stewart last night asked his guest, author David Rakoff, to explain the warning label posted on the cover of his new book: "No inspirational life lessons will be found in these pages."

"The book is meant to be a defense of pessimism, melancholy, sadness," Rakoff said. "All the emotions a self-selecting group, we can just call them ... Jews," he joked.

Laughing hysterically, Stewart said: "Did not see that coming!"

"That baseline way you see the world is as value neutral as having brown eyes," Rakoff continued. "There's nothing particularly wrong with being more pessimistic than optimistic. Optimism is broad-based non-detail oriented thinking; pessimism is detail oriented thinking."

In the midst of writing his book, however, Rakoff discovered that he had a tumor that was pinching his nerve. "It's great, though," he said!

How about a little pessimism?