Modus Tollendo Ponens/Sequent Form

Theorem

Case 1

\(\ds p \lor q\) \(\) \(\ds \)
\(\ds \neg p\) \(\) \(\ds \)
\(\ds \vdash \ \ \) \(\ds q\) \(\) \(\ds \)

Case 2

\(\ds p \lor q\) \(\) \(\ds \)
\(\ds \neg q\) \(\) \(\ds \)
\(\ds \vdash \ \ \) \(\ds p\) \(\) \(\ds \)


Also known as

The Modus Tollendo Ponens is also known as the Disjunctive Syllogism, abbreviated D.S.


Sources

  • 1973: Irving M. Copi: Symbolic Logic (4th ed.) ... (previous) ... (next): $2$ Arguments Containing Compound Statements: $2.1$: Simple and Compound Statements