Modus Tollens - Relation To modus Ponens

Relation To modus Ponens

Every use of modus tollens can be converted to a use of modus ponens and one use of transposition to the premise which is a material implication. For example:

If P, then Q. (premise -- material implication)
If Q is false, then P is false. (derived by transposition)
Q is false. (premise)
Therefore, P is false. (derived by modus ponens)

Likewise, every use of modus ponens can be converted to a use of modus tollens and transposition.

Read more about this topic:  Modus Tollens

Famous quotes containing the words relation to and/or relation:

    The difference between objective and subjective extension is one of relation to a context solely.
    William James (1842–1910)

    The adolescent does not develop her identity and individuality by moving outside her family. She is not triggered by some magic unconscious dynamic whereby she rejects her family in favour of her peers or of a larger society.... She continues to develop in relation to her parents. Her mother continues to have more influence over her than either her father or her friends.
    Terri Apter (20th century)