Browse the Topics, Table of Contents, and Index
Follow us:
Twitter Facebook

3.4 Fallacies in Logic

3.4 Fallacies in Logic
<
>
  • 9. Bluffing at Cards

    Draw a set diagram to analyze the conclusion. (See Example 3 and Example 4.)

    When Jack is bluffing, he sets a chip on his cards. Jack set a chip on his cards, so I know he's bluffing.

    • Worked-Out Solution

      Here is one possible invalid syllogism.

      Premise: If Jack is bluffing, then he sets a chip on his cards.
      Premise: Jack set a chip on his cards.
      Conclusion: Therefore, Jack is bluffing.

      This type of fallacy is called affirming the consequent.

      Premise: If P, then Q.
      Premise: Q.
      Conclusion: Therefore, P.

      In the first premise, Q is called the consequent. The name affirming the consequent comes from the fact that the second premise states that Q is true.

      Here is one way to draw a diagram to analyze this fallacy.

      Note about Fallacies

      Stating that a syllogism is a fallacy simply means that the conclusion was not obtained by logical deduction. It does not mean that the conclusion of the syllogism is false.

    Comments (0)

    These comments are not screened before publication. Constructive debate about the information on this page is welcome, but personal attacks are not. Please do not post comments that are commercial in nature or that violate copyright. Comments that we regard as obscene, defamatory, or intended to incite violence will be removed. If you find a comment offensive, you may flag it.
    When posting a comment, you agree to our Terms of Use.

      ______    ______     _____   __   __   __   __  
     /_____//  /_   _//   / ___//  \ \\/ //  \ \\/ // 
     `____ `    -| ||-    \___ \\   \ ` //    \   //  
     /___//     _| ||_    /    //    | ||     / . \\  
     `__ `     /_____//  /____//     |_||    /_//\_\\ 
     /_//      `-----`  `-----`      `-`'    `-`  --` 
     `-`                                              
    
    Showing 0 comments
    Subscribe by RSS
    There are no comments.
  • 10. Friendly Behavior

    Draw a set diagram to analyze the conclusion. (See Example 3 and Example 4.)

    When Rich wants a favor, he starts acting really friendly. Rich has been acting really friendly today, so I know he wants something.

    Comments (0)

    These comments are not screened before publication. Constructive debate about the information on this page is welcome, but personal attacks are not. Please do not post comments that are commercial in nature or that violate copyright. Comments that we regard as obscene, defamatory, or intended to incite violence will be removed. If you find a comment offensive, you may flag it.
    When posting a comment, you agree to our Terms of Use.

     __   __    _____     ____      _____     ______  
     \ \\/ //  |  ___||  |  _ \\   |  ___||  /_   _// 
      \   //   | ||__    | |_| ||  | ||__      | ||   
      / . \\   | ||__    | .  //   | ||__     _| ||   
     /_//\_\\  |_____||  |_|\_\\   |_____||  /__//    
     `-`  --`  `-----`   `-` --`   `-----`   `--`     
                                                      
    
    Showing 0 comments
    Subscribe by RSS
    There are no comments.
  • 11. Family Traits

    Draw a set diagram to analyze the conclusion. (See Example 3 and Example 4.)

    Greg's friend Dylan is very conservative. Greg concludes that everyone in Dylan's family must be very conservative.

    • Worked-Out Solution

      Here is one way to draw a diagram to analyze the conclusion.

    Comments (0)

    These comments are not screened before publication. Constructive debate about the information on this page is welcome, but personal attacks are not. Please do not post comments that are commercial in nature or that violate copyright. Comments that we regard as obscene, defamatory, or intended to incite violence will be removed. If you find a comment offensive, you may flag it.
    When posting a comment, you agree to our Terms of Use.

      _____    _    _     ______   _    _     _  _   
     /  ___|| | || | ||  /_   _// | || | ||  | \| || 
    | // __   | || | ||  `-| |,-  | || | ||  |  ' || 
    | \\_\ || | \\_/ ||    | ||   | \\_/ ||  | .  || 
     \____//   \____//     |_||    \____//   |_|\_|| 
      `---`     `---`      `-`'     `---`    `-` -`  
                                                     
    
    Showing 0 comments
    Subscribe by RSS
    There are no comments.
  • 12. Power Outage

    Draw a set diagram to analyze the conclusion. (See Example 3 and Example 4.)

    Erica awakens at midnight and discovers the power is out at her house. She looks out her window and sees that all of her neighbors' windows are dark. She concludes that they must have lost their power too.

    Comments (0)

    These comments are not screened before publication. Constructive debate about the information on this page is welcome, but personal attacks are not. Please do not post comments that are commercial in nature or that violate copyright. Comments that we regard as obscene, defamatory, or intended to incite violence will be removed. If you find a comment offensive, you may flag it.
    When posting a comment, you agree to our Terms of Use.

     __   _     ______    _____      ___     _    _   
    | || | ||  /_   _//  / ____||   / _ \\  | \  / || 
    | '--' ||   -| ||-  / //---`'  / //\ \\ |  \/  || 
    | .--. ||   _| ||_  \ \\___   |  ___  ||| .  . || 
    |_|| |_||  /_____//  \_____|| |_||  |_|||_|\/|_|| 
    `-`  `-`   `-----`    `----`  `-`   `-` `-`  `-`  
                                                      
    
    Showing 0 comments
    Subscribe by RSS
    There are no comments.
  • 13. Buying a Present

    Draw a set diagram to analyze the conclusion. (See Example 3 and Example 4.)

    Kyle is buying a dress for his wife. He knows she doesn't like the color blue. So, he picks out a yellow dress and concludes that she will like it because it isn't blue.

    • Worked-Out Solution

      Here is one way to draw a diagram to analyze the conclusion.

    Comments (0)

    These comments are not screened before publication. Constructive debate about the information on this page is welcome, but personal attacks are not. Please do not post comments that are commercial in nature or that violate copyright. Comments that we regard as obscene, defamatory, or intended to incite violence will be removed. If you find a comment offensive, you may flag it.
    When posting a comment, you agree to our Terms of Use.

      ______   _    _                ___      _____   
     /_   _// | || | ||   ____      / _ \\   |__  //  
       | ||   | || | ||  |    \\   | / \ ||    / //   
      _| ||   | \\_/ ||  | [] ||   | \_/ ||   / //__  
     /__//     \____//   |  __//    \___//   /_____|| 
     `--`       `---`    |_|`-`     `---`    `-----`  
                         `-`                          
    
    Showing 0 comments
    Subscribe by RSS
    There are no comments.
  • 14. Approval of Tattoos

    Draw a set diagram to analyze the conclusion. (See Example 3 and Example 4.)

    Kimberly's mother doesn't approve of boys with tattoos. Kimberly's new boyfriend doesn't have any tattoos, so she concludes that her mother will approve of him.

    Comments (0)

    These comments are not screened before publication. Constructive debate about the information on this page is welcome, but personal attacks are not. Please do not post comments that are commercial in nature or that violate copyright. Comments that we regard as obscene, defamatory, or intended to incite violence will be removed. If you find a comment offensive, you may flag it.
    When posting a comment, you agree to our Terms of Use.

     _____      _____     _  __     ___      _____   
    |  __ \\   |  ___||  | |/ //   / _ \\   / ____|| 
    | |  \ ||  | ||__    | ' //   | / \ || / //---`' 
    | |__/ ||  | ||__    | . \\   | \_/ || \ \\___   
    |_____//   |_____||  |_|\_\\   \___//   \_____|| 
     -----`    `-----`   `-` --`   `---`     `----`  
                                                     
    
    Showing 0 comments
    Subscribe by RSS
    There are no comments.
  • 15. Buying a Pizza

    Draw a set diagram to analyze the conclusion. (See Example 3 and Example 4.)

    Tom is ordering pizza for his friends. He recalls that his friend David doesn't like pepperoni. So, he orders a pizza with mushrooms and concludes that David will eat it because it doesn't have pepperoni on it.

    • Worked-Out Solution

      Here is one way to draw a diagram to analyze the conclusion.

    Comments (0)

    These comments are not screened before publication. Constructive debate about the information on this page is welcome, but personal attacks are not. Please do not post comments that are commercial in nature or that violate copyright. Comments that we regard as obscene, defamatory, or intended to incite violence will be removed. If you find a comment offensive, you may flag it.
    When posting a comment, you agree to our Terms of Use.

      ______    _____    _____     __   __    _____   
     /_____//  |  ___|| |  __ \\   \ \\/ //  |__  //  
     `____ `   | ||__   | |  \ ||   \ ` //     / //   
     /___//    | ||__   | |__/ ||    | ||     / //__  
     `__ `     |_____|| |_____//     |_||    /_____|| 
     /_//      `-----`   -----`      `-`'    `-----`  
     `-`                                              
    
    Showing 0 comments
    Subscribe by RSS
    There are no comments.
  • 16. Feeling Sick

    Draw a set diagram to analyze the conclusion. (See Example 3 and Example 4.)

    I am feeling sick this morning. It must be because of the sushi I ate last night. Everyone who ate the sushi must be sick by now.

    Comments (0)

    These comments are not screened before publication. Constructive debate about the information on this page is welcome, but personal attacks are not. Please do not post comments that are commercial in nature or that violate copyright. Comments that we regard as obscene, defamatory, or intended to incite violence will be removed. If you find a comment offensive, you may flag it.
    When posting a comment, you agree to our Terms of Use.

     _    _      ___                 ___     _____    
    | || | ||   / _ \\      ___     / _ \\  |  __ \\  
    | || | ||  | / \ ||    /   ||  / //\ \\ | |  \ || 
    | \\_/ ||  | \_/ ||   | [] || |  ___  ||| |__/ || 
     \____//    \___//     \__ || |_||  |_|||_____//  
      `---`     `---`       -|_|| `-`   `-`  -----`   
                             `-`                      
    
    Showing 0 comments
    Subscribe by RSS
    There are no comments.
©Larson Texts, Inc. All Rights Reserved.