Syllogisms

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๐Ÿง  The Detectiveโ€™s Guide to Syllogisms

Imagine youโ€™re a detective solving mysteries. You gather clues (statements), connect them together, and figure out what MUST be true. Thatโ€™s exactly what syllogisms are!


Whatโ€™s a Syllogism?

A syllogism is like a logic puzzle with two clue statements that help you reach a conclusion.

Think of it like this:

  • Your mom says: โ€œAll fruits are healthyโ€
  • She also says: โ€œAn apple is a fruitโ€
  • You figure out: โ€œSoโ€ฆ an apple must be healthy!โ€ ๐ŸŽ

You just solved a syllogism!


๐ŸŽฏ Syllogism Statements: The Building Blocks

Every syllogism uses four types of statements. Letโ€™s learn them with a simple trick: A, E, I, O

The Four Statement Types

Type Name Pattern Example
A Universal Positive ALL ___ are ___ All dogs are animals
E Universal Negative NO ___ are ___ No cats are birds
I Particular Positive SOME ___ are ___ Some students are singers
O Particular Negative SOME ___ are NOT ___ Some birds are not eagles

Memory Trick! ๐ŸŽช

ALL โ†’ Affirm All Eliminate โ†’ Exclude Everyone Include โ†’ Include some Items Omit โ†’ Omit some Objects

Examples That Click!

Type A (All are):

  • All chocolates are sweet ๐Ÿซ
  • All teachers are humans
  • All squares are shapes

Type E (None are):

  • No fish are mammals ๐ŸŸ
  • No circles are squares
  • No stones are alive

Type I (Some are):

  • Some kids are tall
  • Some flowers are red ๐ŸŒน
  • Some doctors are women

Type O (Some are not):

  • Some animals are not wild
  • Some cars are not expensive ๐Ÿš—
  • Some fruits are not sweet

๐Ÿ”ต Venn Diagrams: Your Secret Weapon

Imagine you have circles that overlap. Each circle represents a group of things. This is your Venn Diagram - the detectiveโ€™s map!

How to Draw Each Statement Type

graph TD A["Statement Type"] --> B["Type A: ALL"] A --> C["Type E: NO"] A --> D["Type I: SOME"] A --> E["Type O: SOME NOT"] B --> F["Circle inside Circle"] C --> G["Circles apart"] D --> H["Circles overlap"] E --> I["Part outside"]

Type A: โ€œAll X are Yโ€

Example: All cats are animals

Picture this: Draw a small circle labeled โ€œCatsโ€ completely INSIDE a bigger circle labeled โ€œAnimalsโ€

    โ•ญโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ•ฎ
    โ”‚    Animals      โ”‚
    โ”‚   โ•ญโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ•ฎ     โ”‚
    โ”‚   โ”‚ Cats  โ”‚     โ”‚
    โ”‚   โ•ฐโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ•ฏ     โ”‚
    โ•ฐโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ•ฏ

Why? Because EVERY cat sits inside the animal group!

Type E: โ€œNo X are Yโ€

Example: No fish are birds

Picture this: Two circles that DONโ€™T touch at all

    โ•ญโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ•ฎ    โ•ญโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ•ฎ
    โ”‚ Fish  โ”‚    โ”‚ Birds โ”‚
    โ•ฐโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ•ฏ    โ•ฐโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ•ฏ

Why? Fish and birds have NOTHING in common!

Type I: โ€œSome X are Yโ€

Example: Some doctors are singers

Picture this: Two circles that OVERLAP a little bit

    โ•ญโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ•ฎ
    โ”‚ Docs  โ•ญโ”ผโ”€โ”€โ”€โ”€โ”€โ”€โ•ฎ
    โ”‚       โ”‚โ”‚ โœ“    โ”‚
    โ•ฐโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ•ฏโ”‚Singers
             โ•ฐโ”€โ”€โ”€โ”€โ”€โ”€โ•ฏ

Why? At least one person is BOTH a doctor AND a singer!

Type O: โ€œSome X are not Yโ€

Example: Some birds are not eagles

Picture this: The โ€œBirdsโ€ circle with part of it OUTSIDE the โ€œEaglesโ€ circle

    โ•ญโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ•ฎ
    โ”‚   Birds     โ”‚
    โ”‚  โ•ญโ”€โ”€โ”€โ”€โ”€โ”€โ•ฎ   โ”‚
    โ”‚โœ“ โ”‚Eaglesโ”‚   โ”‚
    โ”‚  โ•ฐโ”€โ”€โ”€โ”€โ”€โ”€โ•ฏ   โ”‚
    โ•ฐโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ•ฏ

Why? Some birds (like sparrows โœ“) exist OUTSIDE the eagle group!


๐Ÿ” Drawing Conclusions: The Detectiveโ€™s Method

Now comes the exciting part - solving the mystery!

The Golden Rules

Rule 1: Match the Middle Term

  • Find the word that appears in BOTH statements
  • This is your โ€œbridgeโ€ connecting everything

Rule 2: Follow the Logic Flow

graph TD A["Statement 1"] --> B["Middle Term"] C["Statement 2"] --> B B --> D["Conclusion"]

Rule 3: What Goes In, Must Come Out

  • If you use โ€œAllโ€ and โ€œAllโ€ โ†’ You can get โ€œAllโ€ or โ€œSomeโ€
  • If ANY statement is negative โ†’ Conclusion is negative
  • If ANY statement is particular โ†’ Conclusion is particular

Step-by-Step Example ๐ŸŽฏ

Given:

  1. All doctors are intelligent (Type A)
  2. All intelligent people are respected (Type A)

Step 1: Find the middle term

  • โ€œIntelligentโ€ appears in both! Thatโ€™s our bridge.

Step 2: Draw the Venn Diagram

โ•ญโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ•ฎ
โ”‚       Respected             โ”‚
โ”‚    โ•ญโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ•ฎ        โ”‚
โ”‚    โ”‚  Intelligent  โ”‚        โ”‚
โ”‚    โ”‚   โ•ญโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ•ฎ   โ”‚        โ”‚
โ”‚    โ”‚   โ”‚Doctorsโ”‚   โ”‚        โ”‚
โ”‚    โ”‚   โ•ฐโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ•ฏ   โ”‚        โ”‚
โ”‚    โ•ฐโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ•ฏ        โ”‚
โ•ฐโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ•ฏ

Step 3: Read the conclusion

  • Doctors are INSIDE Intelligent
  • Intelligent is INSIDE Respected
  • Therefore: All doctors are respected! โœ“

Another Example (Mixed Types)

Given:

  1. All roses are flowers (Type A)
  2. Some flowers are red (Type I)

Step 1: Middle term = โ€œFlowersโ€

Step 2: Draw carefully

    โ•ญโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ•ฎ
    โ”‚    Flowers       โ”‚
    โ”‚ โ•ญโ”€โ”€โ”€โ”€โ”€โ•ฎ   โ•ญโ”€โ”€โ”€โ•ฎ  โ”‚
    โ”‚ โ”‚Rosesโ”‚   โ”‚Redโ”‚  โ”‚
    โ”‚ โ•ฐโ”€โ”€โ”€โ”€โ”€โ•ฏ   โ•ฐโ”€โ”€โ”€โ•ฏ  โ”‚
    โ•ฐโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ•ฏ

Step 3: What can we conclude?

  • โŒ โ€œAll roses are redโ€ - WRONG! (Roses might not overlap with Red)
  • โŒ โ€œSome roses are redโ€ - WRONG! (We canโ€™t be sure they overlap)
  • โœ“ No definite conclusion about roses and red!

โ“ Possibility Questions: The โ€œWhat Ifโ€ Game

These questions ask: โ€œCould this POSSIBLY be true?โ€

The Magic Word: โ€œPossibilityโ€

When you see words like:

  • โ€œCan beโ€
  • โ€œMay beโ€
  • โ€œPossiblyโ€
  • โ€œCould beโ€

Youโ€™re playing a different game! Now youโ€™re asking: โ€œIs there any chance this is true?โ€

The Secret Technique ๐Ÿ”ฎ

For possibility to be TRUE:

  • The conclusion just needs to NOT be impossible
  • If diagrams COULD overlap, itโ€™s possible!

For possibility to be FALSE:

  • The conclusion must be DEFINITELY wrong
  • The diagrams make it IMPOSSIBLE

Example: Possibility Question

Given:

  1. All apples are fruits
  2. All fruits are healthy

Question: โ€œCan some apples be unhealthy?โ€

Analysis:

โ•ญโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ•ฎ
โ”‚      Healthy        โ”‚
โ”‚   โ•ญโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ•ฎ    โ”‚
โ”‚   โ”‚   Fruits   โ”‚    โ”‚
โ”‚   โ”‚  โ•ญโ”€โ”€โ”€โ”€โ”€โ”€โ•ฎ  โ”‚    โ”‚
โ”‚   โ”‚  โ”‚Applesโ”‚  โ”‚    โ”‚
โ”‚   โ”‚  โ•ฐโ”€โ”€โ”€โ”€โ”€โ”€โ•ฏ  โ”‚    โ”‚
โ”‚   โ•ฐโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ•ฏ    โ”‚
โ•ฐโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ•ฏ

Answer: NO! โŒ

  • All apples are INSIDE healthy
  • Itโ€™s IMPOSSIBLE for any apple to be unhealthy
  • The possibility is FALSE

Another Possibility Example

Given:

  1. Some cats are black
  2. Some black things are scary

Question: โ€œCan some cats be scary?โ€

Analysis:

  • Cats overlap with Black
  • Black overlaps with Scary
  • COULD cats overlap with Scary?
    โ•ญโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ•ฎ
    โ”‚  Cats   โ•ญโ”ผโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ•ฎ
    โ”‚         โ”‚โ”‚  Black โ”‚โ•ญโ”€โ”€โ”€โ”€โ”€โ”€โ•ฎ
    โ•ฐโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ•ฏโ”‚        โ”‚โ”‚Scary โ”‚
               โ•ฐโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ•ฏโ•ฐโ”€โ”€โ”€โ”€โ”€โ”€โ•ฏ

Answer: YES! โœ“

  • Itโ€™s POSSIBLE that some cats are in the scary region
  • We canโ€™t prove it, but we canโ€™t disprove it either
  • The possibility is TRUE

Quick Possibility Checklist โœ…

Scenario Possibility Answer
Definite YES from statements Possible โœ“
Definite NO from statements Not Possible โœ—
Neither proven nor disproven Possible โœ“

๐ŸŽ“ Master Tips for Success

The 5-Second Strategy

  1. Identify statement types (A, E, I, O)
  2. Spot the middle term
  3. Draw quick Venn diagrams
  4. Check if conclusion follows
  5. Verify for possibility questions

Common Traps to Avoid โš ๏ธ

Trap 1: Reversing โ€œAllโ€

  • โ€œAll cats are animalsโ€ does NOT mean โ€œAll animals are catsโ€
  • The bigger group contains the smaller!

Trap 2: โ€œSomeโ€ Confusion

  • โ€œSomeโ€ means โ€œat least oneโ€ (could be all!)
  • Never assume โ€œsomeโ€ means โ€œonly someโ€

Trap 3: Possibility vs Certainty

  • โ€œPossibleโ€ โ‰  โ€œDefinitely trueโ€
  • If something CAN happen, itโ€™s possible

The Confidence Booster ๐Ÿ’ช

Remember:

  • Syllogisms are just puzzles
  • Every puzzle has rules
  • Once you know the rules, you ALWAYS win!
graph TD A["Read Statements"] --> B["Identify Types"] B --> C["Find Middle Term"] C --> D["Draw Venn Diagram"] D --> E["Check Conclusion"] E --> F["Victory! ๐Ÿ†"]

๐ŸŒŸ Final Takeaway

Youโ€™re now a Syllogism Detective!

Remember the story:

  • Statements are your clues
  • Venn Diagrams are your map
  • Conclusions are your solution
  • Possibilities are your โ€œwhat-ifsโ€

Go solve those logic puzzles with confidence! ๐ŸŽฏ

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