Known Unknowns 195 y/ : fx J 5 Sy s : RE, | i Senge oon A 7 -.. ays eo mk. p “< 4 2 Se ‘neh re sa r" Pe. ae - i cyth - i ee STAM VEWTON PAM EA j _ = ’ Newton's Principia PM In 1890, the Cambridge mathematicians Alfred North Whitehead and Bertrand Russell embarked on the mammoth task of writing out all the rules of mathematics and publishing them ina set of books called Principia Mathematica. Every rule is written down in meticulous detail. The books are heavy going and look like more like computer programs than text. They set out precisely what you can, and cannot, do with numbers, and are the most impenetrable textbook you will ever read. Just to give you a flavor here is one line where Russell proves 1+1=2. It has taken about 100 pages of densely packed equations to get to this point! #5443. F:.a,¢el.D:anB=A.=.avBe2 From this proposition it will follow, when arithmetical addition has been defined, that 1+ 1 = 2, One Plus One Equals Two, PM PM is a 3-volume set of books. Volume One costs £480 on Amazon. This is a significant work and a collector's item. The last time a first edition volume came up at auction in 2007 it went for over £800. Cambridge University Press printed only 750 copies and I suspect they HOUSE_OVERSIGHT_015885