D265 - Critical Thinking - Reason and Evidence

PROPOSITIONS

PROPOSITIONS

Are statements that can be true or false

NON-PROPOSITONS

Are sentences that are not statements about matters of fact or fiction. They do not make a claim that can be true or false.

SIMPLE PROPOSITIONS

Have no internal logic structure, meaning whether they are true or false does not depend on whether a part of them is true or false. They are simply true or false on their own. (Example: Harry Potter wears glasses. The sky is blue.)

COMPLEX PROPOSITIONS

Have internal logic structure, meaning they are composed of simple propositions. Whether they are true or false depends on whether their parts are true or false. (Example: The sky is blue, but it does not look blue to me right now. The cat ate the food, but he did not like it. The GDP of Canada is either $3 trillion or $12 trillion.)

Words used to identify Independent Propositions

AND, OR, EITHER, BUT, IF, THEN.

CONCLUSION INDICATORS

THEREFORE, SO, IT FOLLOWS THAT, HENCE, THUS, ENTAILS THAT, WE MAY CONCLUDE THAT, IMPLIES THAT, WHEREFORE, AND AS A RESULT.

PREMISE INDICATORS

BECAUSE, FOR, GIVEN THAT, AS, SINCE, AS INDICATED BY.

DEDUCTIVE ARGUMENTS

Arguments where the premises guarantee or necessitate the conclusion.

-mathematical arguments, logical arguments, arguments from definition.

INDUCTION ARGUMENTS

Arguments where the premises make the conclusion probable.

-analogies, authority, causal inferences, extrapolations, etc.

INFERENCE TO THE BEST EXPLANATION OR ABDUCTION

Arguments where the best available explanation is chosen as the correct explanation.

FORMAL FALLACY

Concerns the structure of an argument

INFORMAL FALLACY

Concerns the informational content of an argument

A FORMAL FALLACY IS A TYPE OF

Bad Argument Structure

Which piece of information would be the most helpful to know in assessing the credibility of a news story?

Whether the name of the author and the publication are identified

Which questions are most appropriate for evaluating the credibility of an information source?

Who funded it? & Does it try to get you to distrust other sources?

While researching a topic on the internet, a student encounters two different websites, one of that looks more official than the other and includes tables, charts, and statistics, while the other does not.

What is the line of reasoning this student should employ to determine which site is more credible?

It is not feasible to determine which site is more credible from the information provided.

In which way should an information source be approached if it is stating that it is the only source of real information and that other sources cannot be trusted?

Skeptically, because the source may lack credibility.

PRINCIPLE OF CHARITY

The principle of charity suggests we should try to understand ideas before criticizing them.

Which of the following are reasons for applying the principle of charity?

It is morally right to give others the benefit of the doubt.

It allows for a clearer understanding of the issue.

Smith is committed to the belief that technological advancement is always beneficial and thus never detrimental to human life. Smith reads a carefully written and sufficiently argued essay in which the author contends that the human adoption of any new technology involves both advantages and disadvantages to its adopters. Since Smith is a loyal technophile, Smith accepts the author's claims about the advantages of technology but rejects the author's claims about the disadvantages of technology.

Which cognitive bias is Smith demonstrating?

Confirmation Bias

CONFIRMATION BIAS

the tendency to interpret new evidence as confirmation of one's existing beliefs or theories.

COGNITIVE BIAS

a systematic thought process caused by the tendency of the human brain to simplify information processing through a filter of personal experience and preferences.

HEURISTICS

are practical rules of thumb that manifest as mental shortcuts in judgment and decision-making.

Which sentence reflects strong critical thinking?

"In any event, our purpose is to better understand the relevant issues so that we may make an informed decision on the topic."

Since inflation is rising rapidly, and because we are approaching the point at which reversal is not possible, it follows that we need to institute a new economic policy, and we need to act quickly.Which two statements contain premises of the given argument?

We are approaching the point at which reversal is not possible. & Inflation is rising rapidly.

"Products manufactured in our country are the best because we make the best automobiles," declared Kennedy. Which two descriptors best characterize Kennedy's comments?

An inference & A weak argument & A proposition

Which two sentences are propositions?

Lending helps stimulate capital investment. & A strong economy is vital to national security.

I have grown bored since last week. Which descriptor accurately characterizes this sentence?

Proposition

People should pay their taxes since paying taxes is the right thing to do. Which type of logic error is this an example of?

Begging the question

One should not speed because speeding is wrong.Which type of logic error is this an example of?

Begging the question

My opponent argues that kangaroos can hop because hopping is something that kangaroos are able to do. Since my opponent has committed the fallacy of begging the question, one must infer that their conclusion is false, and that kangaroos cannot hop. Which type of logic error is this an example of?

The fallacy fallacy

If Bo is kind, then Bo is wealthy. Bo is wealthy. Therefore, Bo is kind. This is an example of which type of logic error?

Affirming the consequent

Which type of logic error is the following argument an example of? "My opponents argue that all giraffes have long necks because anyone who disagrees is a fool. Since my opponents are guilty of the ad hominem fallacy, we must infer that their conclusion is false, and that giraffes do not have long necks."

The fallacy fallacy

Usually when home team fans come out smiling and celebrating at the conclusion of a match, that means the home team won. At the conclusion of the match, many home team fans came out smiling and celebrating. I, therefore, concluded that the home team won. Which term describes this argument?

Inductive

I have seen the sun rise every day for many years. I, therefore, conclude that the sun will rise again tomorrow. Which term describes this argument?

Cogent

All bears are wild. Smokey is a bear. Therefore, Smokey is wild. Which term describes the argument?

Deductive

Which statement is accurate regarding bias in information sources?

All sources have bias, but some are more credible than others.

A news outlet issues a correction and an apology for incorrect information it published. In the absence of further information, what does this news outlet's action suggest about its credibility?

The source appears credible because it is concerned with accuracy.

Which two characterizations are most accurate regarding the credibility of information sources?

The credibility of sources spans a spectrum. & Sources may lack credibility for a variety of reasons.

Why is identifying the author essential in determining a source's credibility?

It helps to determine if the author has relevant expertise.

What is a logical step for critical thinkers to take if they are uncertain about the reliability of a source?

Verify the reliability of a source by cross-referencing with additional source materials.

Which statement represents a logical reaction to a source claiming to be free from bias?

"This can't be true because all sources contain bias."

How could podcasts, newscasts, and talk radio be less biased?

By featuring experts who offer contrary viewpoints

What are two ways in which the internet has complicated a critical thinking approach to finding reliable sources?

Sources are more easily located yet not consistently credible. & Sources are more easily located but still need to be verified.

Which factor should people focus on when evaluating internet-based information sources for credibility?

Content

Why should people read other articles published by the same source when they locate an article of interest on the internet?

To determine whether the source publishes sensationalized or overtly biased stories

A person encounters an internet source with a headline of "This is NOT a hoax!" Which conclusion would be reasonable for this person to make?

The content is sensationalized.

For which two reasons do critical thinkers follow the principle of charity?

To discover the truth & To present a more convincing argument

Which two descriptions accurately characterize the nature of human beliefs?

Subject to bias & Sometimes irrational

Why can heuristics be advantageous?

They enable individuals to make quick decisions.

An individual read a report that professional athletes spend an average of thirty hours per week exercising at the gym. Based on this report, the individual concludes that people who belong to a gym spend an average of thirty hours per week exercising. Which concept does this conclusion illustrate?

Selection bias & Anchoring

Quinn favors strict industry regulations. Robin disagrees because they would increase costs for many businesses and stifle the economy. Robin does, however, understand and acknowledge that industrial operations have environmental and social impacts and that regulatory measures may help prevent unnecessary harm. Which argumentation concept does this passage illustrate?

The principle of charity & Heuristics

Which argumentation concept does the following passage illustrate? "Some people point to the large number of unidentified flying object sightings and the discovery of many earth-like planets in the universe as evidence of extraterrestrial life. I don't take this evidence seriously, though, because I do not believe in extraterrestrial life."

Confirmation bias

A person is buying a car. The car salesperson initially quotes a base price. The buyer relies on this initial quote to make a purchasing decision despite the subsequent addition of options that significantly increase the final price. Which cognitive bias is the buyer exhibiting?

Anchoring and adjustment

A university student surveys incoming freshmen to understand how students at the university feel about a proposed tuition increase. Which statements are true regarding this statistical sample?

It is not representative. & It is not random.

Alex notices that many of the news articles, blogs, social media posts, and other information she sees on the internet reinforce her belief that the government is conspiring against her. Based on this information, which conclusion can Alex reasonably have regarding her view on the issue?

Her suspicion is correct. & She cannot conclude anything.

Why do strong critical thinkers monitor their own biases?

To minimize their biases & To understand how their biases influence their thinking

A person notices that many of the news articles, blogs, social media posts, and other information he sees on the internet mirror his personal likes and dislikes. Based on this information, what can this person reasonably conclude?

Algorithms may be linking him with like-minded information.

95% of American citizens are billionaires. Sam is an American citizen. Therefore, Sam is a billionaire. Which set of terms classify this argument?

Valid and unsound & Strong and uncogent

A person is considering what transportation to use when visiting a friend in a different city. The first thing that comes to mind is a recent news story about a train crash. They decide that the train is not a safe travel option. What kind of bias are they exhibiting?

Availability bias

"Peyton is an excellent dentist, so she sings well." Which statement represents the hidden assumption that would make this argument valid?

All excellent dentists sing well.

Which argument contains the general-specific pattern?

Dogs are a subspecies of a wolf and collie is a breed of dog, so collies are wolves.

Ren is an excellent barista, so he is a master chess player. Which statement represents the hidden assumption that would best complete this argument?

Ren is very analytical. & Anyone who is an excellent barista must be a master chess player.

Traces of ammonia have been found in Mars' atmosphere. So there must be life on Mars.Which statement summarizes the hidden assumption in the given argument?

Only living things produce ammonia.

"All dogs have four legs. Grover is a dog, because Grover barks like a dog. So Grover has four legs." Which statement represents indirect support?

Grover barks like a dog.

"If magicians can pull rabbits out of hats, then magic is real. Magicians can pull rabbits out of hats. Therefore, I know that magic is real." Which two statements represent conjoint support when mapping this example to a body of propositions?

If magicians can pull rabbits out of hats, then magic is real. & Magicians can pull rabbits out of hats.

Which two sentences reflect strong critical thinking?

My opponent's position is contrary to mine; my opponent, however, raises some good questions. & I am unsure of the answer; I will need to research the issue further.

Which two statements best characterize the following argument?"Coffee has caffeine; therefore, it has stimulating effects."

The argument includes a single premise. & The argument includes a single conclusion.

"There are not any good seafood restaurants in this city. I tried two, and they were both terrible." Which fallacy of weak induction best describes this example?

Hasty generalization

A flight attendant accidentally spills a drink on a passenger. The passenger tells a friend that the flight attendants for the airline are incompetent.Which fallacy of weak induction best describes this example?

Hasty generalization

A teacher talks with a student about failing to turn in homework. The student replies by expressing a desire to dress up as a superhero for Halloween. Which response best matches this fallacy of relevance?

Red herring

Either everyone will devour this pecan pie, or they will choose another dessert. Which two statements accurately describe this proposition?

The proposition mistakes causation for correlation. & The proposition contains black and white thinking. & The proposition includes a false dichotomy.

Which fallacy of weak induction best describes the following example? "If we allow the children to stay home from school today, they will expect to stay home every time it snows. Next they will expect to stay home whenever it rains, when it is too cold, too hot, or even too nice outside. Eventually the children will stay home from school every day."

Slippery slope

A soccer fan buys a jersey with his favorite player's name and number on the back. When the player's performance decreases, the fan attributes it to the jersey he bought. Which fallacy of weak induction best describes this argument?

Post hoc, ergo propter hoc

Equivocation Fallacy

The fallacy of equivocation occurs when a key term or phrase in an argument is used in an ambiguous way, with one meaning in one portion of the argument and then another meaning in another portion of the argument.

hasty generalization fallacy

The hasty generalization fallacy is sometimes called the over-generalization fallacy. It is basically making a claim based on evidence that it just too small. Essentially, you can't make a claim and say that something is true if you have only an example or two as evidence.

appeal to ignorance fallacy

This fallacy occurs when you argue that your conclusion must be true, because there is no evidence against it.

Slippery slope fallacy

A slippery slope fallacy occurs when someone makes a claim about a series of events that would lead to one major event, usually a bad event. In this fallacy, a person makes a claim that one event leads to another event and so on until we come to some awful conclusion.

post hoc ergo propter hoc fallacy

Post hoc ergo propter hoc is an informal fallacy that states: "Since event Y followed event X, event Y must have been caused by event X." It is often shortened simply to post hoc fallacy

Shifting the burden of proof fallacy

Shifting the burden of proof, a special case of argumentum ad ignorantium, is the fallacy of putting the burden of proof on the person who denies or questions the assertion being made. The source of the fallacy is the assumption that something is true unless proven otherwise. EX: One example of the burden of proof fallacy is someone who claims that ghosts exists, but doesn't prove this, and instead shifts the burden of proof to others, by stating that anyone who disagrees should prove ghosts don't exist.

Confirmation bias

Confirmation bias is the tendency of people to favor information that confirms their existing beliefs or hypotheses. Confirmation bias happens when a person gives more weight to evidence that confirms their beliefs and undervalues evidence that could disprove it.

Anchoring bias

Anchoring bias is a cognitive bias that causes us to rely too heavily on the first piece of information we are given about a topic. When we are setting plans or making estimates about something, we interpret newer information from the reference point of our anchor, instead of seeing it objectively.

selection bias

Selection bias is a distortion in a measure of association (such as a risk ratio) due to a sample selection that does not accurately reflect the target population. EX: Selection bias also occurs when people volunteer for a study. Those who choose to join (i.e. who self-select into the study) may share a characteristic that makes them different from non-participants from the get-go

sound argument

Soundness: An argument is sound if it meets these two criteria: (1) It is valid. (2) Its premises are true.

valid argument

A valid argument is an argument in which the conclusion must be true whenever the hypotheses are true. EX: "It rains only if I carry an umbrella" can be rewritten as "If it rains, then I carry an umbrella."

"All citizens of Egypt speak Arabic." can be rewritten as "If someone is a citizen of Egypt, then they speak Arabic."

unsound argument

An unsound argument is either an invalid argument or a valid argument with at least one false premise. EX: All dogs are mammals. Therefore, dogs are cows. The above argument contains true premises, but it is invalid since the conclusion doesn't logically follow from the premises. Therefore, it is also an unsound argument.

strong argument

A strong argument is a non-deductive argument that succeeds in providing probable, but not conclusive, logical support for its conclusion.

cogent argument

A cogent argument is an inductive argument that is both strong and all of its premises are true.

uncogent argument

An uncogent argument is an inductive argument that is either weak or has at least one false premise.

Denying the Antecedent

also known as inverse error and fallacy of the inverse, is a logical fallacy whereby someone fallaciously makes an inverse deduction in a conditional statement. It takes one cause as a condition for something else to occur and then states that the latter won't occur when the condition is observed to be untrue.

representativeness

is a logical fallacy whereby someone fallaciously makes an inverse deduction in a conditional statement. It takes one cause as a condition for something else to occur and then states that the latter won't occur when the condition is observed to be untrue.

Affirming the Consequent

is a logical fallacy that involves taking a true statement and assuming the converse form would be true as well. Formally, we can represent this fallacy as follows: If X is the case, then Y is also the case. Y is true, so X must be true as well.

anchoring and adjustment

the tendency to judge the frequency or likelihood of an event by using a starting point (called an anchor) and then making adjustments up or down (a cognitive heuristic where a person starts off with an initial idea and adjusts their beliefs based on this starting point.)

availability

estimating the likelihood of events based on their availability in memory; if instances come readily to mind (perhaps because of their vividness), we presume such events are common EX: two girls saw a plane crash on the news and cancel their flight presuming they will meet the same fate.

Principle of Charity

we should choose the reconstructed argument that gives the benefit of the doubt to the person presenting the argument

the fallacy fallacy

is a logical fallacy that occurs when someone assumes that if an argument contains a logical fallacy, then its conclusion must be false.

Inference

A conclusion one can draw from the presented details. EX: "if there is a storm, then the office is closed." means "if the office is closed, then I don't go to work."

weak argument

a non-deductive argument that fails to provide probable support for its conclusion.