PREFACE vii 



the benefit of vitally important discoveries, not yet 

 published, by my friend Mr Ludwig Wittgenstein. 



Since my purpose was to illustrate method, I have 

 included much that is tentative and incomplete, for it is 

 not by the study of finished structures alone that the 

 manner of construction can be learnt. Except in regard 

 to such matters as Cantor's theory of infinity, no finality 

 is claimed for the theories suggested ; but I believe that 

 where they are found to require modification, this will 

 be discovered by substantially the same method as that 

 which at present makes them appear probable, and it is 

 on this ground that I ask the reader to be tolerant of 

 their incompleteness. 



Cambridge, 

 June 1 9 14. 



