Logic Review

Logic Basics

100

True or false?

An argument cannot be true or false

True: only the sentences that make up an argument can be true or false. 

200

How many conclusions can an argument have?

One

300

Define the word "premise."

A sentence that is meant to support the conclusion of an argument.

400

How many premises can an argument have? 

Any number.

500

In a valid argument, it is impossible for the premises to be [         ] and the conclusion to be [           ] at the same time. 

True, False. A valid argument guarantees that its conclusion is true as long as all its premises are true.

Properties of Arguments

100

True or False? Both inductive and deductive arguments can be good arguments. 

True

200

Which part or parts of an argument can be true or false?

The premises and/or conclusion

300

What do we call an inductive argument in which the premises support the conclusion?

A strong induction

400

What do we call a deductive argument in which the premises support the conclusion?

Valid deduction

500

We know that argument is valid but unsound. What do we therefore know about its premises? You have to be precise on this answer.

At least one of its premises is false. 

Properties of Arguments 2

100

Valid deduction + All true premises = ?

Sound

200

True or False: For all types of arguments, if the premises do not strongly support the conclusion, it is a bad argument. 

True

300

True or False or Neither?

A valid deduction is a good argument.

Neither: Even a valid argument can be bad if it doesn't have true premises. 

400

Is there any type of argument that absolutely guarantees a true conclusion? If so, what is it?

Yes--a sound deduction

500

For each form: identify as either valid or invalid

Form A:  If P, then Q. Q. Therefore, P.

Form B: If P, then Q. P. Therefore, Q.

Form C: If P, then Q. Not Q. Therefore, not P.

Form D: If P, then Q. Not P. Therefore, not Q. 

A: invalid

B: valid

C: valid

D: invalid

Four Common Forms

100

Valid or Invalid?

Form: Modus Ponens

1. If P, then Q

2. P

C: Q

Valid

200

Valid or Invalid?

Form: Modus Tollens

1. If P, then Q

2. not Q

C: not P

Valid

300

Valid or Invalid?

Form: Denying the Antecedent

1. If P, then Q

2. not P

C: not Q

Invalid

400

Valid or Invalid?

Form: Affirming the Consequent

1. If P, then Q

2. Q

C: P

Invalid

500

Make your own argument in the form of Modus Tollens. It can be sound or unsound.

Something in the form of:

Valid or Invalid?

Form: Modus Tollens

1. If P, then Q

2. not Q

C: not P