How To Spot a Logical Fallacy Part 4

Fallacy of division – assuming that something true of a composite thing must also be true of all or some of its parts.

  • A is part of B.
  • B has property X.
  • Therefore, A has property X.
    • The second grade in Jefferson elementary eats a lot of ice cream
    • Carlos is a second-grader in Jefferson elementary
    • Therefore, Carlos eats a lot of ice cream
  • His house is about half the size of most houses in the neighborhood. Therefore, his doors must all be about 3 1/2 feet high.
  • Exception: When a part of the whole has a property that, by definition, causes the part to take on that property.
    • My 102-year-old neighbor is a card-carrying member of an organization of thugs that requires its members to kick babies.  Therefore, my neighbor is a thug

Fallacy of quoting out of context (contextomy, contextomy; quotation mining) – selective excerpting of words from their original context to distort the intended meaning – we will cover both the below in more detail later

  • As a straw man argument, it involves quoting an opponent out of context in order to misrepresent their position (typically to make it seem more simplistic or extreme) in order to make it easier to refute. It is common in politics.
  • As an appeal to authority, it involves quoting an authority on the subject out of context, in order to misrepresent that authority as supporting some position
    • David: Can you believe that the president said, “fat people are losers”?
    • Sam: Where did you hear this?
    • David: I read it in a headline on BrightBert News.
    • Sam: He actually said, “People who say, ‘fat people are losers’ are not only cruel, but they are also wrong as well as being irrational.”
  • Exception: People often use “you’re taking that out of context” to soften something that would otherwise be hard to swallow, yet they are unable to explain adequately how it makes sense in any other context.

False dilemma (false dichotomy, fallacy of bifurcation, black-or-white fallacy) – two alternative statements are given as the only possible options when, in reality, there are more.

  • There are people who routinely engage in black-and-white thinking, an example of which is someone who categorizes other people as all good or all bad.
  • You are either with God or against him.
    • Explanation: As Obi-Wan Kenobi so eloquently puts it in Star Wars episode III, “Only a Sith deals in absolutes!”  There are also those who simply don’t believe there is a God to be either with or against.
  • Exception: There may be cases when the number of options really is limited.  For example, if an ice cream man just has chocolate and vanilla left, it would be a waste of time insisting he has mint chocolate chip. 

Historical fallacy – a set of considerations is thought to hold good only because a completed process is read into the content of the process which conditions this completed result.

  • Dave: For five generations, the men in our family went to Stanford and became doctors, while the women got married and raised children.  Therefore, it is my duty to become a doctor.
  • Kaitlin: Do you want to become a doctor?
  • Dave: It doesn’t matter — it is our family tradition.  Who am I to break it?
  • Exception: Victimless traditions that are preserved for the sake of preserving the traditions themselves do not require any other reason.