The law of crossing means that if you cross a Distinction, then cross it again, the result is the same as doing nothing.

Henning Genz recounts that the world was full, “there was no room for nothingness”. Democritus and the atomists found a use for empty space: it provides room for atoms to move. To maintain the primacy of the natural numbers, the Pythagoreans had to banish irrational numbers into the void. There is nothing between 1 and 2. Aristotle identified the void as the ground of distinction: […]

After working with Laws of Form for over a decade, William Bricken learned to recognize the depths to which Spencer Brown had deconstructed our notions of Truth and Rationality.

The concepts of Distinctions and Labels come from the book Laws of Form, by G. Spencer-Brown. In his book, Spencer-Brown introduces the two following principles on which the previous discussion is based.