Old Fallacies, Emotional Fallacies, Groupthink Sign In HW Due Quiz! Review Quiz! Fallacies Review New Emotional Fallacies Fallacies and evaluating arguments For Next time: Read Chapter 4:

Quiz! Diagram the structure of the argument below: On the basis of [1] and [2], [3]. Since [3], [4]. [5] also implies [4]. Because [4] and [6] we can deduce [7].

Quiz! Diagram the structure of the argument below. Number the claims ( ex- [1] = philosophy is awesome) and then draw the argument diagram. What's the best way to avoid making bad decisions? Taking a critical thinking course will probably be most effective because it makes you aware of potential cognitive biases that can influence your choices. On top of that, it helps you understand the difference between a good argument and a bad argument and if you understand that then you can avoid making bad decisions.

Quiz! Which, if any, of the following terms below are vague: (a) Philosophy 202: Critical Thinking (b) Enormous (c) Applesauce (d) Premeditated (e) Boring

Quiz! The inference being made below is an example of what fallacy (mistake in reasoning)? The lifespan of the average Chihuahua is about 15 years so I can expect Pepe, my new Chihuahua, to live until around 2026.

Quiz! Rewrite the sentence below to remove as much ambiguity as possible. In a second sentence, explain why you resolved the ambiguity in the specific way that you did. Flying planes can be dangerous

Fallacies We have already mentioned fallacies quite a bit Fallacies, we said, are common mistakes in thinking Fallacies can seem really convincing but we should try to avoid them The presence of a fallacy in an argument should give us reason to question its soundness (if deductive) or its strength (if inductive) Can you give me any examples of fallacies we've already looked at?

Familiar Fallacies Fallacy of Composition  Assuming groups share the same properties as its members Fallacy of Division  Assuming members share the same properties as the group The Planning Fallacy  Neglecting past experience with familiar tasks when making predictions about task duration or difficulty

More Familiar Fallacies Ad Hominem –Responding to an argument by criticizing its source instead of by responding to the claims found in it Begging the Question –We mentioned arguments that beg the question last time during our discussion of problems that sometimes arise when we use definitions –How did we define begging the question again?

Begging the Question Begging the question: when you assume the truth of your conclusion at the outset of an argument It is a mistake in reasoning to presume that your argument will be successful For example: “Affirmative action can never be fair or just because you cannot remedy one injustice with another injustice.”

Begging the Question: another example *Dinosaur Comics

Ad Hominem We mentioned Ad Hominem during our discussion of cognitive biases Recall that we said that many fallacies can be the result of cognitive biases Ad Hominem attacks, for example, may stem from belief bias (I disagree with you therefore you must be wrong) or from negativity bias (I don't like you so you must be wrong) In each case, it is a mistake to assume that the source of an argument is necessarily relevant to its content

Ad Hominem: Examples (A): If we hit the beach at 6am then we should just be hitting high tide so the surf should be good (B): You were never really good at making decisions, you're probably wrong about this The problem with Ad Hominem attacks is that they leave the actual argument entirely untouched

A Word of Warning Ad Hominem always involves a personal attack but not every instance of a personal attack in an argument is an instance of Ad Hominem You commit the fallacy of Ad Hominem only if the attack is meant as a direct response or counter-argument to a claim For example: (A): It's raining outside right now (B): Look outside, it's not raining you idiot. In this case (B) is being mean but not resorting to Ad Hominem

Scapegoating Scapegoating is a fallacious kind of emotional fallacy To scapegoat is to assume that one individual or group is responsible for a complex issue It is almost always unlikely that such an individual is truly entirely responsible in the way implied For example: “Obama has ruined this country” or “Religion is responsible for most of the world's problems”

Scapegoating Scapegoating is a mistake in reasoning (a fallacy) because it proposes a simplistic solution to what is likely a complex problem Scapegoating is also one of the most popular and common fallacies committed (especially in political rhetoric) Scapegoating is also often the result of several of the cognitive biases we've already looked at: belief bias, negativity bias, framing effects

Red Herring We commit the Red Herring fallacy when we introduce information that is irrelevant to a claim as if it were relevant For example: (A): I think I could probably graduate more quickly if I took 4 classes this quarter instead of 3 (B): College is a waste of time and you go into so much that debt that it's not even worth it The information introduced by (B), even if true, is entirely irrelevant to (A)'s claim even though they both seem to be speaking about the same thing

Why care? Next week we are going to go beyond reconstructing arguments and begin to evaluate them Being able to spot mistakes in reasoning or problems with vagueness or ambiguity in a claim can make a big difference in how an argument is evaluated Some arguments will only appear valid (remember Spot the reptile) but in fact be invalid Some inductive arguments may appear superficially strong but contain fallacies that expose their weaknesses

For Next Time Read Chapter 4: