5.101 The truth-functions of every number of elementary propositions can be written in a schema of the following kind:

(TTTT)(p, q) Tautology (if p then p, and if q then q.) [pp . qq]
(FTTT)(p, q) in words: Not both p and q. [~(p . q)]
(TFTT)(p, q) ” ” If q then p. [qp]
(TTFT)(p, q) ” ” If p then q. [pq]
(TTTF)(p, q) ” ” p or q. [pq]
(FFTT)(p, q) ” ” Not q. ~q
(FTFT)(p, q) ” ” Not p. ~p
(FTTF)(p, q) ” ” p or q, but not both. [p . ~q : ∨ : q . ~p]
(TFFT)(p, q) ” ” If p, then q; and if q, then p. [pq]
(TFTF)(p, q) ” ” p
(TTFF)(p, q) ” ” q
(FFFT)(p, q) ” ” Neither p nor q. [~p . ~q or p | q]
(FFTF)(p, q) ” ” p and not q. [p . ~q]
(FTFF)(p, q) ” ” q and not p. [q . ~p]
(TFFF)(p, q) ” ” q and p. [q . p]
(FFFF)(p, q) Contradiction (p and not p; and q and not q.) [p . ~p . q . ~q]

Those truth-possibilities of its truth-arguments, which verify the proposition, I shall call its truth-grounds.