# Modus Ponens

Topics: Logic, Argumentative, Modus ponens Pages: 1 (276 words) Published: July 17, 2011
Modus Ponens
An argument with two premises, one of which is a conditional claim and another which endorses the antecedent of that conditional. The valid conclusion of a modus ponens argument will endorse the consequent of the conditional. (An English translation of the Latin name "modus ponens" is something like "the direct route" or "direct way.") Argument Form: 1. If A then B2. A B

An example: 1. If Sam is laughing then he's amused.2. Sam is laughing. Sam is amused.

Premise
A claim offered as evidence to support an argument's conclusion; one of the arguer's reasons for the truth of the conclusion. Most arguments have more than one premise. Conditional Claim
A claim that says that the truth of one claim depends on the truth of another, or that the situation described in one claim depends on the situation described in the other. For example, the claim "If cows are mammals then cows give milk" is claiming that cows giving milk depends on cows being mammals. When most clearly expressed, conditionals take the form "If A then B." The claim in position A is called the antecedent.

The claim in position B is called the consequent. (That's "consequent," not "consequence.") Go back to the example about cows and milk. The antecedent is "cows are mammals" and the consequent is "cows give milk." The conditional is claiming that "cows are mammals" is sufficient to claim "cows give milk." The conditional is true when the antecedent is a sufficient condition for the consequent. But there are many other ways to express a conditional claim besides the form "If A then B."