Symposium on Alfred North Whitehead Correspondence.
Now I feel like writing to the Library to get the transcript of the letter online. After all they say "The six-page letter was handwritten in 1936 by Whitehead to his former student and personal assistant, Henry S. Leonard. In the letter, Whitehead responds to and comments on an essay written by Leonard regarding the conflict between speculative philosophy and logical positivism. Whitehead comments on the relationship between philosophy and science, and also reveals his attitudes toward, and appraisals of, his collaborator Bertrand Russell, Ludwig Wittgenstein and the father of logical positivism, Rudolf Carnap."
Maybe the letter is online somewhere? Wish I knew.