Why does valid argumentation matter

If this is possible, the argument is invalid. Validity and invalidity apply only to arguments, not statements. For our purposes, it is just nonsense to call a statement valid or invalid. True and false apply only to statements, not arguments. For our purposes, it is just nonsense to call an argument true or false. All deductive arguments aspire to validity. One cannot validly infer from 2 that Clinton is a duck.

Indeed, one and the same sentence can be used in different ways in different contexts. Consider the statement:. It is not clear what the logical form of this statement is. The King and Queen are visiting dignitaries. Visiting dignitaries is always boring. Therefore, the King and Queen are doing something boring.

Because of the difficulty in identifying the logical form of an argument, and the potential deviation of logical form from grammatical form in ordinary language, contemporary logicians typically make use of artificial logical languages in which logical form and grammatical form coincide.

The use of an artificially constructed language makes it easier to specify a set of rules that determine whether or not a given argument is valid or invalid. In short, a deductive argument must be evaluated in two ways. First, one must ask if the premises provide support for the conclusion by examing the form of the argument. If they do, then the argument is valid. Then, one must ask whether the premises are true or false in actuality.

Only if an argument passes both these tests is it sound. However, if an argument does not pass these tests, its conclusion may still be true, despite that no support for its truth is given by the argument. Note: there are other, related, uses of these words that are found within more advanced mathematical logic.

Moreover, an axiomatic logical calculus in its entirety is said to be sound if and only if all theorems derivable from the axioms of the logical calculus are semantically valid in the sense just described. The author of this article is anonymous. The IEP is actively seeking an author who will write a replacement article.

Validity and Soundness A deductive argument is said to be valid if and only if it takes a form that makes it impossible for the premises to be true and the conclusion nevertheless to be false.

The following argument is valid, because it is impossible for the premises to be true and the conclusion nevertheless to be false: Elizabeth owns either a Honda or a Saturn. Consider, then an argument such as the following: All toasters are items made of gold. However, the following argument is both valid and sound: In some states, no felons are eligible voters, that is, eligible to vote.

For example, consider these two arguments: All tigers are mammals. Identify the role learn more. Identify the principle Quick guide. Identify the principle Learn more. Match structure Quick guide. Match structure Learn more. Match principles Quick guide. Match principles Learn more. Identify a flaw Quick guide. Identify a flaw Learn more. Match a flaw Quick guide. It just means succeeding in establishing conclusive support for its conclusion.

Of course, the premises of this argument are false. But claiming that an argument is valid is not to claim that the premises are true. Validity is about succeeding in providing conclusive support for the conclusion, if the premises were true.

So if the conclusion is unlikely to be true when the premises are true, then the argument is weak. Game over. The answer to this question is contextual. As a lecturer, my standards are very strict. My goal is to make sure that you learn from your mistakes. I need to change my standards there. So establishing that an argument is strong in court is quite demanding. We want to minimise the mistakes we make.

Madison is a vegetarian. Therefore, Madison is probably healthy. If the premises are true, what are the chances that Madison is healthy? She might not be. Hence, this argument is strong. Want to keep learning?

This content is taken from The University of Auckland online course,. This content is taken from The University of Auckland online course. Share this post. See other articles from this course. This article is from the online course:. Join Now. News categories.

Other top stories on FutureLearn. We explore the current business landscape in India, identity the 5 best startup opportunities and …. Find out about some of the best startup ideas for the Philippines, as well as …. We explore the challenges and opportunities of the healthcare system in India, looking at how ….