Logic and Reasoning

Difference between logic and reasoning?

Logic is the framework that is based on facts to draw a conclusion, while Reasoning is the process that uses logic with context from other variables like beliefs and emotions.

What is a Syllogism? + Example

A conclusion drawn from 2 premise.

All Humans are mortal.

Socrates is a human.

Therefore, Socrates is mortal.

What Reasoning does a Syllogism employ?

Deductive Reasoning

What are the parts of a syllogism?

Major premise: general statement

Minor Premise: specific statement relating to general statement

Conclusion: Logical inference between the two

What is an enthymeme?

Abbreviated Syllogism

An argument with a hidden premise, which the audience infers

Enthymeme examples

He is yawning; therefore, he is sleepy.

All humans are mortal, so I am mortal.

Formal vs Informal Fallacies

Formal Fallacies are arguments with an invalid structure, while informal Fallacies are arguments with errors in the content.

Deductive vs Inductive Reasoning

Deductive is a general premise to a specific conclusion, while inductive is a specific observation to a general conclusion.

Ad Hominem

Attacking the person rather than the argument.

“Shes not credible because shes single and hasn’t had children”

Ad Ignorantiam

Claiming something is true because it hasn’t been proven to be false or Vice Versa.

“No one has proven that UFOs don’t exist, so they must be real.”

Ad Misericordiam

Appealing to emotions instead of giving actual logic to persuade an audience.

“You can’t fire me! My family will starve.”

Ad Populum (Bandwagon)

Assuming something is correct because it is popular.

“This movie is a bestseller, so it must be a good movie.”

Appeal to (false) Authority

Stating a claim is true because an expert said it is, even without evidence.

“I should buy this brand of toothpaste because a famous dentist said it’s the best.”

Appeal to tradition

Using historical preferences to prove that a historical preference is correct.

“This medicine has been used for centuries, so it must be effective.”

Cherry picking

Using select evidence to persuade the audience to accept a position, ignoring the evidence that doesn’t support the position.

“A company might emphasize a specific percentage increase in customer base in their annual report, while obscuring a downward trend in profit margins or increased operating costs.”

Circular Reasoning

A circle of reasoning with no useful information. A proposition is supported by a premise, which is supported by the proposition. The evidence used to support a claim is just a repetition of the claim itself.

“The President of the United States is a good leader, because they are the leader of this country.”

Composition

If some parts are true, then the whole part must be true.

“A car is made of rubber because its tires are” or “A team has the best players so they must be the best team”

Cum Hoc Ergo Propter Hoc

Concluding that one thing causes another as they are regularly associated

“I always get a headache when I sleep with my shoes on, so sleeping with shoes on must cause headaches.”

Division

If the whole part is true, then some/all parts are also true

“All students at this school are smart, so she must be smart,” or “The company is successful, so every employee must be highly skilled.”

False Dichotomy/False Dilemma

Only presenting 2 possible options when more options exist

“You’re either going to college or you’re wasting your life,” or “The vaccine either stops 100% of infections, or its completely ineffective.”

Hasty Generalization

Conclusion based on a sample size of information rather than the statistics that are more in line with the situation.

“I met two people from NYC, and they were both rude. Therefore, all people from NYC are rude,” or “I saw one dog chasing a cat, so all dogs must be mean to cats.”

No True Scotsman

Denying the validity of other examples to support/defend a generalization and changing the definition of a group to exclude counterexamples. People do this to avoid acknowledging that a generalization isn’t true.

Person A: “No Scotsman puts sugar on his porridge.”

Person B: But my uncle Angus is at Scotsman and he puts sugar on his porridge.”

Person A: “But no true Scotsman puts sugar on his porridge.”

Post Hoc Ergo Propter Hoc

Event B followed Event A, so Event A caused Event B.

“The rooster crows before the sun rises, so the rooster’s crowing causes the sun to rise.”

Slippery Slope

An insignificant event turns into a more significant event, and continues until an ultimate significant event is reached.

“If we allow gun control, the next thing you know, the government will take away all of our rights,” or “If we lower the drinking age, teenagers will start drinking at younger ages and this will lead to more drunk driving accidents.”

Strawman

Substituting an argument with a misrepresented version of the argument.

Person A: “I think we should consider more options for sustainable transportation.”

Person B: “So, you’re saying we should all ban cars and make everyone walk everywhere?”

Sunk Cost

Continuing to invest time and effort into a failing project in an attempt to prevent feeling like work has gone to waste.

“Continuing to pour money into a business that’s already losing money,” or “Continuing to watch a movie you dislike simply because you’ve already paid for the ticket.”