Spencer-Brown G. Laws of form

Laws of Form is an approach to mathematics, and to epistemology, that begins and ends with the notion of a distinction. Nothing could be simpler. A distinction is seen to cleave a domain. A distinction makes a distinction.1) The form
2) Forms taken out of the form
3) The conception of calculation
4) The primary arithmetic
5) A calculus taken out of the calculus
6) The primary algebra
7) Theorems of the second order
8) Re-uniting the two orders
9) Completeness
10) Independence
11) Equations of the second degree
12) Re-entry into the form