The Laws of Form (Spencer-Brown 1969) wikipedia 
, page did not enter the world of mathematical texts without presupposition. The problems to which the text responds, as well as some of the solutions presented, become accessible to a different and possibly deeper understanding when the Laws of Form are considered in the context of the history of mathematics and logic.
SPENCER-BROWN, George, 2008. Wahrscheinlichkeit und Wissenschaft. 2. Aufl. Heidelberg: Carl Auer Verl. ISBN 978-3-89670-626-3.
What does participation mean? ⇒ Unresolvable Indeterminacy