Logical arguments & persuasion in communication

Why does persuasion matter?

We encounter it everyday: in ads, friendships, family, and social media.

Persuasion is about:

Influencing decisions

Helping people see your perspective

Building stronger communication skills

What is a logical argument?

A set of statements where premises support a conclusion.

Types of reasoning

Deductive

Inductive

Abductive

Deductive reasoning

Starts with a general principle and applies to a specific case

Example: all humans need communication - Maria is human - Maria needs communication

Inductive reasoning

Starts with a specific example and build to a general conclusion

Example: Every time my professor pauses before answering, they give a thoughtful response - pausing before answering shows thoughtfulness

Abductive reasoning

Best explanation based on available evidence.

Example: if my friend hasn’t text me back, maybe their phone died.

Persuasion: the 3 appeals (technique to influence)

Tools of persuasion identified by Aristotles

Logos, ethos, and pathos

Logos

Logic: facts, evidence, reasoning.

Example: 9 out of 10 dentist recommend this toothpaste

Ethos

Credibility: trustworthiness, expertise, character

Example: as an dentist with 20 years of experience, i recommend this toothpaste

Pathos

Emotion: feelings, values, identity

Example: Don’t let cavities take way your smile

Logical fallacies

Errors in reasoning that weaken an argument

Ad Hominem (attacking the person)

Occurs when someone attacks their opponent’s character instead of addressing their argument.

Example: you can’t trust him on climate change because he is not a scientist

Strawman argument

Involves misrepresenting opponent’s argument to make it easier to attack.

Example: people who support free college just want to everything handed to them.

False dilemma (either-or fallacy)

Occurs when only two choices are presented, despite more options being available.

Example: either we ban all cars to stop pollution, or the planet is doomed.

Slippery slope

Suggests that taking a minor action will lead to major and sometimes absurd consequences.

Example: if we allow students to redo assignments, they’ll expect to retake the whole class if they fail.

Hasty generalization

Occurs when a conclusion is drawn based on insufficient or unrepresentative evidence.

Example: My friend didn’t get a job after college, so college degrees are useless.

Circular reasoning (begging the question)

Occurs when the argument’s conclusion is assumed in the reasoning.

Example: i am right because i said i am right

Appeal to ignorance

Claims that something is true because it hasn’t been proven false (or viceversa)

Example: No one has ever proven that aliens don’t exist, so they must be real.

Bandwagon fallacy (appeal to popularity)

Occurs when something is deemed true or right simply because it’s popular or many people believe it.

Example: Everyone is using this diet pill, so it must be the best way to lose weight.

Red herring

Introduces an irrelevant point to distract from the main issue.

Example: Why should we worry about the environment when there is unemployment.

Post hoc ergo propter hoc (false cause)

Assumes that because one event happened after another, the first caused the second.

Example: I got sick after visiting that restaurant, so their food must have caused my illness.