5.512
“~p” is true if “p” is false. Therefore in the true proposition “~p” “p” is a false proposition. How then can the stroke “~” bring it into agreement with reality? That which denies in “~p” is however not “~”, but that which all signs of this notation, which deny p, have in common. Hence the common rule according to which “~p”, “~~~p”, “~p∨~p”, “~p.~p”, etc. etc. (to infinity) are constructed. And this which is common to them all mirrors denial.