Philosophy: Logic and Critical Thinking Worksheet

Question 1

Identify the conclusion in this argument: All citizens should have access to accurate information. Public libraries provide free access to reliable sources. Therefore, public libraries deserve public support.

Accepted Answer

The conclusion is that public libraries deserve public support. The first two sentences are reasons offered to support that claim.

Question 2

Decide whether this argument is deductive or inductive: Every triangle has three sides. This shape is a triangle. Therefore, this shape has three sides.

Accepted Answer

This is a deductive argument because the conclusion is meant to follow with certainty from the premises.

Question 3

Decide whether this argument is deductive or inductive: Most students who study a little each day perform well on tests. Maya studies a little each day, so Maya will probably perform well on the test.

Accepted Answer

This is an inductive argument because the conclusion is probable rather than certain.

Question 4

Explain the difference between validity and soundness in deductive logic.

Accepted Answer

Validity means that if the premises are true, the conclusion must be true. Soundness means that the argument is valid and all of its premises are actually true.

Question 5

Test this argument for validity: If a law is unjust, then citizens may criticize it. This law is unjust. Therefore, citizens may criticize this law.

Accepted Answer

The argument is valid. It has the form if P then Q, P, therefore Q, which is called affirming the antecedent or modus ponens.

Question 6

Identify the fallacy in this statement: You should not listen to Jordan's argument about recycling because Jordan once forgot to take out the trash.

Accepted Answer

This is an ad hominem fallacy because it attacks Jordan personally instead of responding to the argument about recycling.

Question 7

Identify the fallacy in this statement: If we allow students to redo one assignment, soon no one will complete any work on time, and the whole grading system will collapse.

Accepted Answer

This is a slippery slope fallacy because it assumes one small action will lead to extreme results without showing enough evidence for the chain of events.

Question 8

Complete the truth table for the conditional statement if P then Q. State when the conditional is false.

Accepted Answer

The conditional if P then Q is false only when P is true and Q is false. In all other cases, the conditional is true.

Question 9

Rewrite this conditional statement as its contrapositive: If a number is divisible by 4, then it is even.

Accepted Answer

The contrapositive is: If a number is not even, then it is not divisible by 4. This is logically equivalent to the original statement.

Question 10

Explain why this reasoning is invalid: If a person is a professional athlete, then the person exercises often. Taylor exercises often. Therefore, Taylor is a professional athlete.

Accepted Answer

The reasoning is invalid because many people exercise often without being professional athletes. The argument commits the fallacy of affirming the consequent.

Question 11

Classify each condition in this statement as necessary, sufficient, or both: Being a square is a condition for being a rectangle.

Accepted Answer

Being a square is sufficient for being a rectangle because every square is a rectangle. It is not necessary because some rectangles are not squares.

Question 12

Find the hidden assumption in this argument: The school should start later because students will learn better if they get more sleep.

Accepted Answer

A hidden assumption is that starting school later will help students get more sleep. Without that assumption, the conclusion is not fully supported.

Question 13

Evaluate this source claim: A social media post says a new medicine works because one famous actor said it helped them. What should a critical thinker consider before accepting the claim?

Accepted Answer

A critical thinker should consider scientific evidence, expert medical sources, clinical studies, possible side effects, and whether one person's experience is enough to support the claim.

Question 14

Make this argument more charitable before criticizing it: People who disagree with the new phone policy just hate rules.

Accepted Answer

A more charitable version is: People who disagree with the new phone policy may believe it is too strict, unfair, or ineffective. This version addresses their possible reasons instead of insulting them.

Question 15

Use an argument map to identify the main claim and two supporting reasons in this passage: Schools should teach media literacy. Students see online claims every day, and they need skills for checking whether sources are trustworthy.

Accepted Answer

The main claim is that schools should teach media literacy. One supporting reason is that students see online claims every day. Another supporting reason is that students need skills for checking whether sources are trustworthy.

Philosophy: Logic and Critical Thinking

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