Description: Rule of Modus Ponens.
The postulated inference rule of propositional
calculus. See e.g. Rule 1 of [Hamilton] p. 73. The rule says, "if
φ is true, and
φ implies ψ, then ψ must also be
true". This rule is sometimes called "detachment", since
it detaches
the minor premise from the major premise. "Modus ponens" is
short for
"modus ponendo ponens", a Latin phrase that means "the
mode that by
affirming affirms" - remark in [Sanford] p. 39. This rule is similar to
the rule of modus tollens mto 167.
Note: In some web page displays such as the Statement List, the
symbols "& " and "⇒
" informally indicate the relationship
between the hypotheses and the assertion (conclusion), abbreviating the
English words "and" and "implies". They are not
part of the formal
language. (Contributed by NM, 30-Sep-1992.) |