Deductive Reasoning

What does deductive reasoning use to form its arguments?

• Observed example

• Patterns

• Facts, definitions, accepted properties and laws of logic

• Specific cases

Using the statements:

If it is Friday, then I will get paid.

It is Friday.

What is the conclusion?

• I will get paid.

• It is Friday.

• I will not get paid.

• It is not Friday.

What can you conclude from the given true statements?

If an animal is a dog, then they like biscuits.

Sammy is a dog.

• Sammy is a Great Dane.

• Sammy is a cat.

• Sammy likes biscuits.

• We can't conclude anything.

Which of the following is a strategy for determining whether an argument is valid?

• Considering whether the conclusion is true.

• Trying to think of a counterexample.

• Considering whether the premises and conclusion are well connected.

If we're in London, then we're in England.

We are not in England.

So, we are not in London.

Which type of hypothetical syllogism is this?

• Modus ponens

• Modus tollens

• Chain argument

• Denying the antecedent

• Affirming the consequent

A deductive argument is an argument that is intended to be valid.

• True

• False

An argument can be both invalid and deductive.

• True

• False

"Look, all the spiders are poisonous, right? You got bit by a spider, so you've definitely been poisoned!"

• A valid deductive argument

• An invalid deductive argument

If I want to keep my financial aid, I'd better study hard.

I do want to keep my financial aid.

Therefore, I'd better study hard.

What type of hypothetical syllogism is this?

• Chain argument

• Affirming the consequent

• Denying the antecedent

• Modus tollens

• Modus ponens