Peirce's Law - Other Proofs of Peirce's Law

Other Proofs of Peirce's Law

Showing Peirce's Law applies does not mean that PQ or Q is true, we have that P is true but only (PQ)→P, not P→(PQ) (see affirming the consequent).

simple proof: 
(p \rightarrow q) \rightarrow p \Rightarrow
\overline{p \rightarrow q} \or p \Rightarrow
\overline{\overline p \or q} \or p \Rightarrow
(p \and \overline q) \or p \Rightarrow
(p \and \overline q) \or (p \and 1) \Rightarrow
p \and (\overline q \or 1) \Rightarrow
p \and 1 \Rightarrow
p.

Read more about this topic:  Peirce's Law

Famous quotes containing the words proofs, peirce and/or law:

    I do not think that a Physician should be admitted into the College till he could bring proofs of his having cured, in his own person, at least four incurable distempers.
    Philip Dormer Stanhope, 4th Earl Chesterfield (1694–1773)

    Truth is that concordance of an abstract statement with the ideal limit towards which endless investigation would tend to bring scientific belief, which concordance the abstract statement may possess by virtue of the confession of its inaccuracy and one-sidedness, and this confession is an essential ingredient of truth.
    —Charles Sanders Peirce (1839–1914)

    It seems to be a law of nature that no man, unless he has some obvious physical deformity, ever is loth to sit for his portrait.
    Max Beerbohm (1872–1956)