Techniques of Philosophical Inquiry

An argument is valid if ...

• the premises necessarily entail the conclusion.

• the conclusion necessarily entails the premises.

• if the premises are true and the conclusion is true.

• If the premises are false but the conclusion is true.

An argument is sound if ...

• the premises are false but the argument is valid.

• it's inductive and the premises are true.

• it's valid and the premises are true.

• if the premises are false and the argument is invalid.

An argument is cogent if ...

• it's deductive and the argument is valid.

• it's inductive and the premises necessarily entail the conclusion.

• it's deductive and the premises are false but the conclusion is true.

• it's inductive and the premises provide good reason for believing the conclusion.

What is the conclusion of the following argument?

"William will probably return wet. He has gone waterskiing and people who go waterskiing usually end up wet."

• William has gone waterskiiing.

• William will probably return wet.

• People who go waterskiing end up wet.

What is the implied premise of this argument?

"Ben worked hard all year, therefore he will pass."

• Ben will pass.

• Ben worked hard all year.

• Working hard ensures that you will pass.

Is the following argument valid?

"Only vegetarians like broccoli. Grace likes broccoli so Grace is a vegetarian."

• Yes

• No

Is the following argument sound?

"Only vegetarians like broccoli. Grace likes broccoli so Grace is a vegetarian."

• Yes

• No

Is the following argument inductive or deductive?

"In the past, ducks have always come to our pond. Therefore, the ducks will come to our pond this summer."

• Inductive

• Deductive

Is the following argument inductive or deductive?

"All horses love hay. Tansy is a horse. Therefore, Tansy will love hay."

• Inductive

• Deductive

Identify the following fallacy:

"You have just committed the Slippery Slope Fallacy. Your conclusion is therefore false."

• Slippery slope

• Fallacy fallacy

• Non-sequiter

• Straw-man