在逻辑中，肯定前件（拉丁语：Modus ponens）是有效的、简单的论证形式（常缩写为MP）:

如果P，则Q。

P能证明Q。

肯定前件规则可以用相继式符号写为：

或用规则形式写为：

In propositional logic, modus ponendo ponens (Latin for "the way that affirms by affirming"; generally abbreviated to MP or modus ponens) or implication elimination is a valid, simple argument form and rule of inference. It can be summarized as "P implies Q; P is asserted to be true, so therefore Q must be true." The history of modus ponens goes back to antiquity.