Logic and Fallacies Overview

Logic

• The study of correct reasoning.
• Aims to distinguish good reasoning from flawed ones.

Argument

• The basic unit of reasoning.
• A method of reasoning where a conclusion is drawn from premises or propositions.
• Parts of an argument: Premise and Conclusion (Conclusion is supported by Premises)

Fallacy

• An error or mistake in reasoning.
• Usually involves an idea that may sound logical, but is deceptive or misleading.
• From Latin 'faller,' meaning 'deception' or 'false'.
• Three broad categories: Irrelevance, Presumption, and Ambiguity.

Fallacies of Irrelevance

• Argumentum ad Hominem

  • Attacks the person making the argument rather than the argument itself.
  • Latin term, 'an argument [or attack] to the man'.
  • Example: Person 1: Logic is an extremely important and useful subject. Person 2: You believe that because you're an idiot and you need logic.

• Argumentum ad Baculum

  • Appeals to force or authority, whether physical or economical.
  • Latin term, 'an appeal to the stick'.
  • Example: A stick may be used to punish a child to force them to behave in ways parents want them to.

• Argumentum ad Misericordiam

  • Appeals to one’s emotions, accepting a conclusion based on pity, anger, love, etc.
  • Latin term, 'an appeal to misery'.

• Tu Quoque Fallacy

  • Justifying wrong actions because someone else has done them.
  • Latin term, 'an appeal to hypocrisy'.
  • Example: Person 1: You can't cut classes today, we have a quiz later. Person 2: Oh, come on, you have no right to lecture me, you have also cut classes.

• Argumentum ad Populum

  • Asserts reasoning is correct simply because most people believe it (Bandwagon).
  • Latin term, 'appeal to the people'.
  • Example: A friend recommends a book because it's a bestseller, even if you prefer different genres.

• Argumentum ad Tradition

  • Believing something is right because it's been done for a long time.
  • Example: A son defends voting for a certain party because his family has always done so.

• Argumentum ad Ignorantiam

  • Argues something must be true or false because it hasn't been proven otherwise.

Fallacies of Presumption

• Petitio Principii

  • An argument where the conclusion is assumed in one of the premises.
  • Example: “You keep failing your exams because you're not smart.”

• Red Herring

  • Attempts to redirect the argument to another issue.
  • Example: Person 1: Sis, my situationship ended, I’m sad. Person 2: You are still lucky, there are starving kids in Africa.

Fallacies of Ambiguity

• Fallacy of Composition

  • Mistakenly assumes that what is true for the parts must also be true for the whole.
  • Example: The boys at the back are noisy, so the whole class is noisy.

• Fallacy of Division

  • We mistakenly assume that what is true for the whole must also be true for all the parts.
  • Example: Section St.X likes it when the teacher gives examples involving K-Pop idols, so everyone in the class must like listening to K-Pop.

• Slippery Slope Fallacy

  • Consists of a sequence of claims that will cause another event, leading to a chain of events.
  • Example: “If I had a flat tire, I wouldn't be able to get to work, which would lead for me to have a sanction, which is bad in my records. Hence, I won’t be able to get a promotion due to a flat tire.”

• False Cause Fallacy

  • Committed when two following events occur, and we jump to the conclusion that the first event caused the second event, even though no connection can be found.

• Fallacy of Equivocation

  • Happens when we use a single term with two or more meanings (an equivocal term) in our argument, leading to confusion.
  • Example:

• Hasty Generalization

  • Made on the basis of insufficient evidence.
  • Example: You have a transit flight via Frankfurt Airport, Germany. On the way to your gate,...