Thursday, June 28, 2012

Logic Lessons pt 4

Fallacies of Diversion

The next set of Material Fallacies are called Fallacies of Diversion. These are ways of diverting attention away from the argument itself. Many people, when they are losing an argument, avoid the substance of the argument.

  1. Ad hominem = attacking the person instead of the issues at hand.

          There are several different type of Ad hominem attacks

          a. “Poisoning the well” = direct attack on trustworthiness to avoid arguing facts. Usually involves slanting. Who here hasn't heard this growing up: “You're just a kid, you don't know what you're talking about?”

          b. “Tu quoque” = “you too.” This is attacking the critic with the same thing the critic accuses you of doing. An example of this would be: “How can you tell me to turn away from sin, when you too are a sinner.” Or a teen says to a parent “You drank when you were in high school, so how can you tell me I can't?”

          c. “Genetic Fallacy” = refuting an idea by showing some suspicious psychological origin of it. As I mentioned in my post on death, non-believers sometimes say that belief in God is based on our fear of death. But this substitutes a logical reason with personal motive. If you said to me, “You don't want to believe that your wife is cheating on you,” I would agree, but it has no bearing on whether or not she is (incedentally, just to protect her honor, let me clarify that she is not).

  1. Ad verecundian = “appeal to reverence”

    This is when there is an illegitimate appeal to authority or an appeal to illegitimate authority. Now, not all appeals to to authority are bad. Sometimes authority is necessary, because we can't be experts on everything. I am not an expert in particle physics and quantum mechanics, so I rely on others. But arguments from authority are the weakest of all arguments, because we have not worked through all the data ourselves, but we are one step removed from the logic.
    Appeals to authority are fallacious when:

    a. they are irrelevant: e.g. movie stars on issues of science
     b. unreliable: e.g. tabloids who have questionable sources
     c. unnecessary: when argument from reason is clear. I don't need a PhD in math to tell me that if a=b and b=c then a=c
    d. dogmatic: claimed with certainty, not probability. Whenever I says “Experts say...” I have to acknowledge that they could be wrong.
    e. uncritical: when there is no good reason to trust authority. I remember when a student told me that removal of priestly celibacy would lead to less pedophilia. When I pointed out that married men, by a larger percentage, have more pedophiles than celibate priests, her response was: “Well, my mom agrees with me.”

  1. Ad baculum = appeal to force or fear instead of reason. 

     Also includes appeal to desire. If your boss says that they will fire you if you agree with them or promote you if you agree, this would be an example of this.

  1. Ad misericordiam = appeal to pity in substitute for an argument.

     I was moderating a debate on euthanasia. One of the debaters said, “I've had a family member who died in great pain. You won't think euthanasia is wrong if you have to live through the same situation.” While experiential knowledge is important, this is a fallacy because it dodges the logical arguments presented by the opponent.

  1. Ad ignominiam = appeal to shame in substitute for argument. 

     If you've ever had someone say to you, “People will laugh at you if you do X,” then this would be a fallacy. Now, if the substance of the argument is what people will or will not laugh at, then this is not a fallacy. But if you said to me, “You shouldn't stand at a prayer vigil outside abortion clinics because people will laugh at you,” this would not address the substance of if my actions are right or wrong.
    As clarification on the difference between shame and guilt. Shame is social. It is relative to society. Guilt is personal. It is based on our own beliefs of moral rightness. Often the two things overlap. Once when I was a kid, as a joke, slapped my dad on the back of the head for saying something I thought was stupid. His faced turned ashen and yelled at me in front of everyone. I still feel guilt about that because it was a horribly disrespectful thing to do to my father, and I know that it was wrong. But I also felt shame, because I knew other people who saw would think I was a bad person. A good example of this distinction is being naked. When we are alone in the shower naked, we don't feel any guilt. But if suddenly the walls to the bathroom fell away and the whole neighborhood saw us, we would feel shame.

  2. Ad populum = believing or doing something because it is popular. Politicians do this all the time. 

     There are 2 types
    a. Appeal to the Masses. This is where we turn to the idea of what normal people think and how they behave. Notice this has been used by citing polls regarding the acceptance of contraceptives in modern society and how that impacts the morality of the contraception mandate in Obamacare.      b. “Snob Appeal.” This happens whenever we disregard an argument because it comes from a place we consider inferior.

7. Ad ignoratiam = appeal to ignorance. This is arguing an idea must be true because we do not know that it is not. This is one that I heard a lot when The DaVinci Code was popular: “I believe Jesus married Mary Magdalene because there is no evidence that says that he did not.” This would be like me saying: “I believe that you are a serial killer because there is no evidence to say that you are not.”


  1. Just for fun- watch any set of political ads- regardless of issue or political party- and count how many of these you can spot.. ;)

    1. Agreed. So many political ads rely on emotion. Not that there's anything wrong with emotion, but here is where knowing this fallacies can protect us again smart-sounding people.

      By the way, "Spot the Political Ad Fallacy" would make a great drinking game.

  2. That was exactly what I was thinking! 'course nobody would be able to drive home afterwards..