Can a valid argument with formally consistent premises have an analytically impossible conclusion? What about the converse?


Is it possible to have a valid argument with a false premise and a true conclusion?

TRUE: A valid argument cannot have all true premises and a false conclusion. So if a valid argument does have a false conclusion, it cannot have all true premises. Thus at least one premise must be false.

Do valid arguments have consistent premises?

A valid argument cannot have premises which are all true and a false conclusion, as the definition of a valid argument is an argument for which there is no possible world in which the premises are all true and the conclusion is false.

Is it possible to have a valid argument with exactly one logically true premise?

No, both valid and invalid arguments can have all true premises and a true conclusion. You would need to determine if it is also possible for the argument to have all true premises and a false conclusion. 7.

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What is a formally valid argument?

An argument is termed formally valid if it has structural self-consistency, i.e. if when the operands between premises are all true, the derived conclusion is always also true. In the third example, the initial premises cannot logically result in the conclusion and is therefore categorized as an invalid argument.

Can an argument with false premises be valid?

A valid argument can have false premises; and it can have a false conclusion. But if a valid argument has all true premises, then it must have a true conclusion.

Can a valid argument have false premises example?

If Elizabeth Taylor is president of the United States, then Elizabeth Taylor must be 35 years of age or older. Elizabeth Taylor is president of the United States. So, Elizabeth Taylor must be 35 years of age or older. For either example, the logic is valid but the premises are false.

What does it mean to have consistent premises?

The book defines a set of premises to be consistent if you can’t deduce a contradiction from the set of premises. It also says that a set of premises is consistent if there is some formula P that is not deducible from the set of premises.

How do you know if an argument is formally valid?

An argument is valid if the premises and conclusion are related to each other in the right way so that if the premises were true, then the conclusion would have to be true as well.

What does formally valid mean?

formally valid in British English

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(ˈfɔːməlɪ ˈvælɪd ) adjective. logic. (of an inference or argument) when the inference is justified by the form of the premises and conclusion alone.

How do you determine if an argument is valid or invalid?

Think hypothetically. Ask, “IF the premises are true, are we locked into the conclusion?” If yes, then the argument is valid. If no, then the argument is invalid.

What do you call an argument that is not valid?

An argument is INVALID just in case it’s NOT VALID.

The truth of the premises doesn’t guarantee the truth of the conclusion. That’s ALL it means to call an argument “invalid”. In particular, it doesn’t imply that the argument is bad. As we’ll see in the next lecture, invalid arguments can still be good arguments.

What is an example of a valid argument?

A valid argument is an argument in which the conclusion must be true whenever the hypotheses are true. In the case of a valid argument we say the conclusion follows from the hypothesis. For example, consider the following argument: “If it is snowing, then it is cold. It is snowing.

Which of the following types of arguments are evaluated with the terms valid and invalid?

Deductive arguments are either valid or invalid, and sound or unsound. A valid deductive argument is one in which it is impossible for the conclusion to be false, if the premises are true. An invalid argument is one in which it is possible for the conclusion to be false, if the premises are true.

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Can a valid argument be unsound?

Another way to put the same idea is that an argument is valid when the truth of its premises guarantees the truth of its conclusion. either invalid or has one or more false premises; so, a valid argument is unsound if and only if it has one ore more false premises.