You have to love a page that begins "You may never have heard the name of the World's Smartest Man, Richard McKeon."
And, further: "To the best of my knowledge, he is the smartest man in known history. For a rough approximation of his brilliance, think of ArIstotle [sic], about 2,000 years SMARTER [sic]."
Wiki begins their entry with the rather more restrained "McKeon is a pivotal but neglected figure in 20th Century American Philosophy. In a career which spanned seven decades, he published 158 articles and 11 books. He received most of the honours possible for an American philosopher, including being given an invitation to deliver the Paul Carus Lectures in 1969."
One more about him.