Critical Thinking: Reason and Evidence - D265 Flashcards
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?
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.
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.
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.
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
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.
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
When people rely on representativeness to make judgments, they are likely to judge wrongly because the fact that something is more representative does not actually make it more likely.
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.
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.
Straw figure
The straw figure or straw man fallacy happens when someone (willfully or mistakenly) misinterprets someone else’s argument or position. The opponent’s argument or position is characterized uncharitably so as to make it seem ridiculous or indefensible. It is a fallacy of relevance because the arguer is attacking an irrelevant argument.
Red Herring
A red herring is a logical fallacy in which irrelevant information is presented alongside relevant information, distracting attention from that relevant information.
Irrelevant Appeals
Any kind of appeal to a factor, consideration, or reason that isn’t relevant to the argument at hand is called an Irrelevant Appeal.
Appeal to Unqualified/False Authority
Appeal to Force
Appeal to Popularity/to the People/Bandwagon
Appeal to Consequences
Appeal to Unqualified Authority
This fallacy is used when a person appeals to a false authority as evidence for a claim. These fallacious arguments from authority are the result of citing a non-authority as an authority.
Appeal to Force
This argument uses force, the threat of force, or some other unpleasant backlash to make the audience accept a conclusion.
Appeal to the People
The fallacy of appeal to appeal to the people consists of arguing that a claim is true because a lot of people believe it, or that a claim is false because a lot of people do not believe it.
Appeal to Consequences
The major fallacy of logos, arguing that something cannot be true because if it were the consequences or outcome would be unacceptable.
A false dilemma
misrepresents an issue by presenting only two mutually exclusive options rather than the full, nuanced range of options
The genetic fallacy
is a fallacy of irrelevance in which arguments or information are dismissed or validated based solely on their source of origin rather than their content.
Appeal to Ignorance
This fallacy occurs when you argue that your conclusion must be true, because there is no evidence against it. This fallacy wrongly shifts the burden of proof away from the one making the claim.
The Texas Sharpshooter
a logical fallacy based on the metaphor of a gunman shooting the side of a barn, then drawing targets around the bullethole clusters to make it look like he hit the target.
