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Lesson 2 of 20 · Logic & Reasoning

Puzzleintermediate

Syllogism Challenges

What You'll Learn

A syllogism is a logical argument with two facts and a conclusion. If Fact 1 and Fact 2 are both true, the conclusion MUST be true. Why does this matter? Formal deductive logic is a skill that will help you in school, in friendships, and in solving real-world problems. People who master this skill make better decisions and understand the world more clearly. Here's the process: Step 1 — Define the challenge. What exactly are you trying to figure out? Being specific about the question is half the battle. Step 2 — Gather information. What facts do you have? What might be missing? Not all information is equally useful — focus on what's relevant. Step 3 — Consider multiple options. Don't stop at your first idea. Challenge yourself to think of at least three alternatives. Often the best answer is one you didn't think of immediately. Step 4 — Evaluate your options. What are the pros and cons of each? What evidence supports each one? Which option has the strongest reasoning behind it? Step 5 — Make your choice and explain your reasoning. "I think ___ because ___" is the formula. Being able to explain your thinking is just as important as getting the right answer. Step 6 — Reflect. Was your approach effective? What would you do differently next time? This reflection step is how good thinkers become great thinkers.

Key Concept: Formal deductive logic

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Think About This

You realize that an assumption you held about formal deductive logic might be wrong. How do you handle updating your beliefs in light of new evidence?

Thinking Steps

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Define

State the problem or question about formal deductive logic in your own words. Be specific.

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Investigate

What evidence or information is available? What might be missing?

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Consider Angles

Look at this from at least two perspectives. What would someone who disagrees say?

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Reason It Out

Connect evidence to your conclusion: 'The evidence shows X, which means Y, because Z.'

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Test Your Thinking

Could you be wrong? What evidence would change your mind? Rate your confidence 1-10.

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Reflect & Connect

What thinking skill did you use? How could you apply this to something in your real life?

Key Points

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Two true premises = one guaranteed conclusion

2

This is called deductive reasoning

3

If the premises are wrong, the conclusion can be wrong too

Key Vocabulary

Deduction

Using general rules to reach a specific conclusion

Fallacy

A mistake in reasoning that makes an argument flawed

Hypothesis

A testable prediction based on evidence

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Why This Matters in Real Life

Lawyers build logical arguments in court. Engineers use logic to design safe bridges. Programmers use it to write code. Logic is everywhere!

Talk About It

Discuss these questions with a friend, parent, or classmate.

  • 1Give a real-world example where formal deductive logic would help you make a better decision.
  • 2What's the most common mistake people make with this kind of thinking?
  • 3How does this thinking skill connect to other subjects you study in school?
  • 4If you had to teach this to a younger student, what's the ONE thing you'd make sure they understood?

Check Your Understanding

Question 1

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What is the main idea of formal deductive logic?