Understanding Fallacies: Formal and Informal Reasoning

• Fallacies are errors or mistakes in reasoning
• Fallacies are committed due to faults in reasoning and validating arguments

Types of Fallacies

• There are two types of fallacies: formal and informal

Formal Fallacies

• Errors in reason due to incorrect structure or form of the argument
• Mostly found in a deductive argument
• All invalid arguments are formal fallacies
• Example:
• Premise 1: If someone is allergic to peanuts, then she does not eat peanut butter.
• Premise 2: Sam does not eat peanut butter.
• Conclusion: Sam is allergic to peanuts.

Informal Fallacies

• Also known as Material Fallacies
• Fallacies due to a mistake in the content of the argument, mainly in the meaning of the words
• These fallacies are somewhat psychologically persuasive or manipulative

Strawman Fallacy

• Misinterpreting and misrepresenting an argument to make it easier to attack
• Example:
• Player 1: “Iwasan natin magkamali sa laro para hindi makapuntos ang kalaban.”
• Player 2: Huwag mo na lang kaya kami ipasok sa laro para hindi tayo matalo. Iyan naman ang gusto mo.

False Dichotomy

• An argument claims to only have two options, when in fact, there is a third option
• Example:
• A boy wants to buy a new cellphone and asks his mom for money.
• The mom can't give it due to budget constraints.
• The student believes his mom doesn't love him because if she loves him, she'll give him money.

False Cause Fallacy

• Perceiving a relationship between two events doesn't mean the cause of an event is another one
• Example:
• "Palaging naghahatid sa kanya iyang matandang yan, siguro tatay niya yan."
• Student I is seeing Student J and an old man when in fact, the old man is their personal driver

Fallacy of Equivocation

• Several meanings of the same word are used in the context of a whole argument
• Example:
• A billboard company might advertise their billboards using a line like: “Looking for a sign? This is it!”

Fallacy of Composition

• Assuming that what is true to a part of something is true to its whole
• Example:
• Some birds can fly, so all birds must be able to fly

Fallacy of Division

• Assuming that what is true to the whole thing is true to its parts
• Example:
• Americans travel a lot. Joy is American, so she must travel a lot.

Appeal to Ignorance

• A statement is neither proven to be true nor false
• A fallacy due to the truth value not being established
• Example:
• I saw a witch flying outside the house. Therefore, witches are real.

Appeal to Inappropriate Authority

• Committed when someone appeals to an authority whose expertise doesn't include the nature of the argument being discussed
• Example:
• “I had a fever last night. My grandmother told me not to take a bath for a few days until I get better."

Appeal to Pity

• Committed when someone appeals to pity to cause the acceptance of the conclusion
• Example:
• "Mom, please consider raising my allowance. There are too many requirements this month for different subjects."

Appeal to Popular Opinion

• Urging people to accept the argument when the majority of the people believe it
• Example:
• Mr. President has high approval ratings; he is therefore doing a good job.

Appeal to Force

• Telling the Human Person threats or something bad will happen if he/she doesn't accept the argument
• Example:
• "Return my money or I'll sue you”.

Ad Hominem

• Attacking the person instead of the argument
• Example:
• “I will never join their group even they are good at researching because they are too mean"

Hasty Generalization

• The premise given doesn't sufficiently support the conclusion due to a lack of evidence
• Example:
• "The man who snatched my purse was from Tondo; therefore, people live there are snatchers."

Begging the Question

• The argument assumes that the context they're trying to prove is true
• Example:
• Don't go to bed yet after taking a shower. Is it really awful for a person to go to sleep after taking a shower?

Slippery Slope Fallacy

• If something is allowed to happen, then something far from the argument will also happen
• Example:
• If students are required to wear uniforms to school, they'll do less shopping at local clothing stores. With less business, the stores will close, which will hurt our local economy

Strawman Fallacy

• This is the distortion of someone else's argument to make it easier to attack or refute.
• Instead of addressing the actual argument of the opponent, one may present a somewhat similar but not equal argument
• Example:
• When a teacher proposes that the class spend more time on math exercises, a parent complains that the teacher doesn't care about reading and writing