Propaganda - Fallacies

Argument Fallacies

An argument fallacy is a reasoning "trick" made up of faulty logic, erroneous assumptions, or irrelevant information meant to distract. It may look like a consistent and compelling argument but is not. You will need to become familiar with the fallacies in order to recognize them.

Faulty Logic

There is a form of logic based on the construction
    a -> b
which represents the premise that the presence of a implies that b is also present. For example, if a is "you go outside into a heavy rain" then b is "you are very wet." If a occurs, then b will follow. It looks like:

Go outside in heavy rain -> Get very wet
There are four ways to use this structure.
  1. Assert that a is true. This is Modus Ponens (affirming the antecedent) reasoning. If a is true, then you can conclude that b is also true. You have gone outside into the rain, so you are soaked. This reasoning is valid.
  2. Assert that a is not true. This attempt at reasoning doesn't work. Consider the above example. Suppose you didn't go out in the rain.. Maybe you took a shower, or fell in the indoor swimming pool. You are very wet, but not from rain. b might be true for some other reason. This reasoning is not valid.
  3. Assert that b is true. This doesn't tell you anything about a. b might be true for more than one reason. You are very wet - for one of a number of possible reasons. This reasoning is not valid.
  4. Assert that b is not true. This is Modus Tollens (denying the consequent) reasoning. If b is not true, then a must also be not true. You are NOT wet, therefore you must not have gone out in the rain. This reasoning is valid.
Notice that only two of the four possibilities are valid. The other two provide no evidence for a conclusion. Detection of either of the two invalid reasonings is cause for caution.

General Fallacies

What follows is a summary of common reasoning fallacies. These things appear to support the conclusion of an argument but really don't. You will notice that the number of these fallacies is large, too large for us to list all of them..

  • Ad Hominem Attack: If you can't refute the argument, attack the person presenting the argument. The intent is to discredit said person. Note that such an attack does not address the issue at hand, but rather constitutes a diversion. Such attacks are rather easy to detect; don't be distracted by them.
  • Appeal to Authority; Some "higher authority" is invoked as evidence in support of a claim. Always be sure to check out that authority. In an ad, saying that "many doctors agree..." is really lame.
  • Appeal to Emotion: A common fallacy. A "sob story" is used to support a claim. The problem is that the sad story doesn't really represent the whole picture.
  • Appeal to Fear: Propagandists (politicians in particular) may try to scare you with fearsome predictions of what "the other guy" will do if elected. These predictions may be pure BS, but if they frighten enough people they will work. The fear device is commonly used in political campaigns.
  • Appeal to the People: A common fallacy of attempting to support a claim on the basis of popularity. Remember that something that "everybody knows" can be wrong.
  • Arguing from Ignorance: A common fallacy of claiming that some hypothesis is true based on lack of information. Think of claiming that something seen in the sky is an alien spacecraft because we have no other explanation at hand at the time. If you have no information, all you can say is that you don't know.
  • Appeal to Tradition: We've always done it this way. That might be true, but it might not constitute a reason to keep doing it this way.
  • Begging the Question: This is simple circular logic. You make a claim, then "support" with a reason whose meaning is simply a restatement of the claim. In other words, the reason is not valid unless the conclusion is valid.
  • Composition: This is an unjustified inference that a property of one component of a whole applies to the whole.
    Molecules cannot be seen by the unaided eye.
    Bricks are made up of molecules
    Therefore, bricks cannot be seen with the unaided eye.
    Note that there are cases where the inference is actually correct. Your job is to recognize the difference.
  • Division: This is the opposite of the fallacy of composition. It is an inference that a property of the whole also applies to all of its parts.
    A common house brick is red.
    A house brick is made up of atoms.
    Therefore, the atoms in the brick are red.
  • Either/Or Fallacy: This is the False Dichotomy fallacy. It consists of framing the issue to make it appear that there are only two options. One option is made to look terrible, with the implication that the other option presented is the only choice. Such situations are usually pretty rare. Be sure to look carefully for more options.
  • Equivocation: This clever trick entails the use of a word in two different senses. The switch in meaning invalidates the reasoning.
  • False Analogy: To facilitate explanation, a complex issue may be portrayed as similar to a simple issue that everyone can understand. The trick with this technique is for the simpler issue to really not be a good comparison, but rather be close enough to pass. With clever design, the misleading simpler model will misdirect thought about the complex issue.
  • False Cause: The order of some sequence or set of events is confused with actual causation. In propaganda the confusion is intentional. See Post Hoc, Ergo Propter Hoc.
  • Hasty Generalization: Simply look at a small sample of some population then generalize it to the whole population.
  • Origin: This is an implication that something is suspect because of its origin.
  • Perfect Solution: This faulty premise makes the claim that, since the proposed action will not solve all of the problem, it is not the desired solution and should be rejected. This is fallacious because most modern problems are complex enough that no single perfect solution exists.
  • Post Hoc, Ergo Propter Hoc: A common fallacy. It confuses temporal relation with causation. The fallacy is that since b came after a, then a must have caused b. Consider that there may be several possibilities for what caused b and the time relationship could be just coincidence.
  • Slippery Slope: This one is used a lot. It argues that if we do a, then there is nothing to stop b from happening. If we do b, then c must surely follow. Obviously, results a, b, and c are undesirable. The fallacy is used as a reason for not doing a. The flaw is that there is usually no causal connection between a, b, and c.
  • Straw Man: The user of this tactic invents some misleading picture of an opponent's ideas so that the fake view can be knocked down easily. Since the original idea has been misrepresented and distorted, the audience may think that the original idea has been knocked down when only the fake straw man view has been hit.


  • Asking the Right Questions; M. Neil Browne & Stuart M. Keeley
  • How to Think About Weird Things; Theodore Schick & Lewis Vaughn