Chunyan Shao (Shandong University)

To learn to think logically

The ability for logical reasoning is a must if you want

to do well in analysis

to do well in evaluation

The capacity for consciously making sense of things, for establishing and verifying facts, and changing or justifying practices, institutions, and beliefs based on new or existing information. (Wikipedia)

So we should… know what things are involved recognize the facts be aware of the practices, institutions

and beliefs have a lot of information

Drawing valid inference through the process of induction, deduction and abduction.

There are three parts involved in reasoning: precondition, rules and conclusion.

Given a precondition, a conclusion, and a rule that the precondition implies the conclusion, they can be explained in the following way:

It is learning the rule after numerous examples of the conclusion following the precondition. E.g.:

The grass has been wet every time it has rained.

Therefore, if it rains tomorrow, the grass will get wet.

Scientists

Hasty Generalization 过度概化 A person travels through a town for

the first time. He sees 10 people, all of whom children. The person then concludes that there are no adult residents in the town.

A faulty generalization by reaching an inductive generalization based on insufficient evidence— essentially making a hasty conclusion without considering all of the variables.

McDonald's and KFC offer foods with little nutrition, and thus we cannot expect any fast food restaurant to provide us with nutritious foods.

Sport can help us relax. Sport can exercise our muscles. Also sport improves our ability to fight against disease. Therefore, sport is good for our health.

Employees are like nails. Just as nails must be hit in the head in order to make them work, so must employees.

Two entities share properties of two or more things, and from this basis inferring that they also share some further property.

The model of the solar system is similar to that an atom, with planets orbiting the sun like electrons orbiting the nucleus. Electrons can jump from orbit to orbit; so we should study ancient records for sightings of planets jumping from orbit to orbit.

Sam: "I think that people can have some affection for their cultural heritage."

Michelle: "You're just like Hitler!"

It is using the rule and its precondition to make a conclusion. E.g.:

When it rains, the grass gets wet. It rained today. Therefore, the grass is wet.

Mathematicians

All men are mortal. John is a man. Therefore, John is mortal.

Dicto Simpliciter (Unqualified generalization) 草率前提

Exercise is good. Therefore, everyone should exercise.

University students abide by the law. Girls love talking about dresses. Going to university is necessary for

one to get a good job. Time is money.

It is using the conclusion and the rule to support that the precondition could explain the conclusion. E.g.:

When it rains, the grass gets wet. The grass is wet. Therefore, it may have rained.

Diagnosticians and detectives

Let’s not take Lily out for picnic. Each time we take her out, it rains.

Lily has nothing to do with raining. She does not cause raining.

There are too many private cars in the street, and the traffic is serious. Therefore it is the increasing private cars that cause serious traffic jams in big cities.

The new mayor took office last January and crime in the streets has already increased 25 percent. The assumption is that having the new mayor caused the increase in crime.

If we don't care about the environment, the world will die in 50 years.

There are many in-between procedures to be defined/explained.

It states that a relatively small first step leads to a chain of related events culminating in some significant effect, much like an object given a small push over the edge of a slope sliding all the way to the bottom.

If you study hard, you will get a high score in the final examination.

If God can do anything, he can make a stone so heavy that he himself cannot lift.

You must have graded my exam incorrectly. I studied very hard for weeks specifically because I knew my career depended on getting a good grade. If you give me a failing grade I'm ruined!

Someone tries to win support for an argument or idea by exploiting their opponent's feelings of pity or guilt.

"Ladies and gentlemen of the jury, look at this miserable man, in a wheelchair, unable to use his legs. Could such a man really be guilty of embezzlement?"

If I hadn’t taught you about those fallacies, you would never know what they are about.

Life is life and fun is fun, but it's all so quiet when the goldfish die.

an argument in which its conclusion does not follow from its premises.

Mary: I wonder how Mrs. Knowles next door is doing.Jim: Did you hear that the convenience store two blocks over got robbed last night? Thieves got away with a small fortune.

Susan is smart; therefore she will receive good grades.

Many smart people do not receive good grades.

We have only two choices: ban nuclear weapons, or destroy the earth.

In fact, other possibilities exist.

Stating that only two alternatives exist when in fact there are more than two.

"Either the nobles of this country appear wealthy, in which case they can be taxed for good; or they appear poor, in which case they are living frugally and must have immense savings, which can be taxed for good."

Nine out of ten of my constituents oppose the bill, therefore it is a bad idea.

This fallacy is sometimes committed while trying to convince a person that a widely popular thought is true.

Everyone's doing it. Google gives more hits when this

spelling is applied, therefore this has to be the correct spelling.

Your exposition is highly correct and valid, but you don't have enough academic certification.

An argument made personally against an opponent, instead of against the opponent's argument.

Attack the messenger, rather than the message.

Candidate George's proposal about zoning is ridiculous. He was caught cheating on his taxes in 2003.

What makes you so smart and all-knowing that you can deny God's existence? You haven't even finished school.

The informal fallacy of presenting an argument that may or may not be logically valid, but fails nonetheless to address the issue in question.

A deliberate attempt to divert a process of enquiry by changing the subject.

Why worry about a few terrorists when we ought to be doing something about acid rain?

Induction, deduction, abduction Hasty Generalization False analogy Dicto Simpliciter Post hoc Slippery slope Ad misericordiam Contradictory premises Hypothesis contrary to fact Non sequitur Either…or Bandwagon

Hominem Red Herring