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.