Question

1. Define validity and soundness.

2. Explain why a valid argument can never have all true premises and a false conclusion.

3. Are invalid arguments weak? Explain your answer.

Answer 1

• 1.An argument form is valid if and only if whenever the premises are all true, then conclusion is true. An argument is valid if its argument form is valid. For a sound argument, An argument is sound if and only if it is valid and all its premises are true.
• 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. Otherwise, a deductive argument is said to be invalid.
• A deductive argument is sound if and only if it is both valid, and all of its premises are actually true. Otherwise, a deductive argument is unsound.
• In effect, an argument is valid if the truth of the premises logically guarantees the truth of the conclusion. 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.
• Elizabeth does not own a Honda.
• Therefore, Elizabeth owns a Saturn.
• A sound argument is one that is not only valid, but begins with premises that are actually true. The example given about toasters is valid, but not sound. However, the following argument is both valid and sound:
• In some states, no felons are eligible voters, that is, eligible to vote.
• In those states, some professional athletes are felons.
• Therefore, in some states, some professional athletes are not eligible voters.
• Here, not only do the premises provide the right sort of support for the conclusion, but the premises are actually true. Therefore, so is the conclusion.
• Due to time limit,remaining questions can be asked as another question,they will be answered,thankyou for your cooperation