WGU D265 Critical Thinking Class

Proposition

A statement that expresses a judgment or opinion. Example: 'It is raining.'

Non-proposition

A statement that cannot be true or false. Example: 'Close the door!'

Argument

A set of propositions where one is claimed to follow from the others. Example: 'All humans are mortal. Socrates is a human. Therefore, Socrates is mortal.'

Non-argument

A statement or group of statements that do not aim to support a conclusion. Example: 'I like apples.'

Premise

A proposition that provides support for a conclusion. Example: 'If it rains, the ground will be wet.'

Conclusion

The proposition that follows from the premises. Example: 'Therefore, the ground is wet.'

Deductive Argument

An argument where the conclusion necessarily follows from the premises. Example: 'All birds have feathers. A sparrow is a bird. Therefore, a sparrow has feathers.'

Inductive Argument

An argument where the conclusion is likely based on the premises. Example: 'The sun has risen in the east every day so far. Therefore, the sun will rise in the east tomorrow.'

Valid/Invalid

Valid if the conclusion logically follows from the premises; invalid if it does not. Example: Valid: 'If it rains, the ground is wet. It rains. Therefore, the ground is wet.' Invalid: 'If it rains, the ground is wet. The ground is wet. Therefore, it rains.'

Sound/Unsound

Sound if it is valid and its premises are true; unsound if it is not. Example: Sound: 'All mammals are warm-blooded. A whale is a mammal. Therefore, a whale is warm-blooded.' Unsound: 'All cats are black. My cat is black. Therefore, all cats are my cat.'

Strong/Weak

Strong if the premises provide good support for the conclusion; weak if they do not. Example: Strong: 'Most swans are white. Therefore, the next swan I see will likely be white.' Weak: 'My friend has a red car. Therefore, all cars must be red.'

Cogent/Uncogent

Cogent if it is strong and has true premises; uncogent if it is not. Example: Cogent: '90% of surveyed students prefer online classes. Therefore, most students prefer online classes.' Uncogent: 'My uncle won the lottery. Therefore, everyone can win the lottery.'

Informal Fallacy

An argument that is logically unsound for lack of well-grounded premises. Example: 'You shouldn't listen to her argument about climate change; she's not a scientist.'

Formal Fallacy

An error in the argument's form or structure. Example: 'All cats are animals. All dogs are animals. Therefore, all cats are dogs.'

Antecedent

The first part of a conditional statement. Example: In 'If it rains, then the ground is wet,' 'it rains' is the antecedent.

Consequent

The second part of a conditional statement. Example: In 'If it rains, then the ground is wet,' 'the ground is wet' is the consequent.

Modus Ponens

A valid form of argument where if 'P implies Q' is true and P is true, then Q is true. Example: 'If it is a dog, then it barks. It is a dog. Therefore, it barks.'

Modus Tollens

A valid form of argument where if 'P implies Q' is true and Q is false, then P is false. Example: 'If it is a dog, then it barks. It does not bark. Therefore, it is not a dog.'

Affirming the Consequent

A formal fallacy where the consequent is affirmed, leading to an invalid conclusion. Example: 'If it rains, the ground is wet. The ground is wet. Therefore, it rained.'

Denying the Antecedent

A formal fallacy where the antecedent is denied, leading to an invalid conclusion. Example: 'If it rains, the ground is wet. It did not rain. Therefore, the ground is not wet.'

The Fallacy Fallacy

Assuming that if an argument contains a fallacy, its conclusion must be false. Example: 'You used a straw man argument; therefore, your conclusion is wrong.'

Credibility of an Information Source

The quality of being trusted and believed in. Example: A peer-reviewed journal is considered a credible source.

Reliability of an Information Source

The consistency of a source in providing accurate information. Example: A news outlet that consistently reports facts accurately is reliable.

Cognitive Bias

Systematic patterns of deviation from norm or rationality in judgment. Example: Overconfidence bias leads individuals to overestimate their knowledge.

Confirmation Bias

The tendency to search for, interpret, and remember information that confirms one's preconceptions. Example: Only reading news articles that support one's political views.

Representativeness Bias

Judging the probability of an event based on how much it resembles a typical case. Example: Assuming a coin toss will yield heads because the previous tosses were all heads.

Anchoring and Adjustment Bias

Relying too heavily on the first piece of information encountered (the 'anchor') when making decisions. Example: If the first price seen for a car is $30,000, subsequent prices will be judged in relation to that.

Availability Bias

Overestimating the importance of information readily available. Example: Believing airplane travel is more dangerous than car travel after hearing about a plane crash.

Selection Bias

A distortion of statistical analysis results due to the method of collecting samples. Example: Surveying only people who visit a particular website may not provide a representative sample.

Heuristic

A simple, efficient rule used to form judgments and make decisions. Example: Using the 'rule of thumb' to estimate costs.

Principle of Charity

The practice of interpreting a speaker's statements in the most rational way possible. Example: Assuming the best intentions behind an opponent's argument.

Direct Support

When a premise directly supports a conclusion. Example: 'It is raining. Therefore, the ground is wet.'

Indirect Support

When a premise supports a conclusion through another premise. Example: 'If it rains, the ground will be wet. It is raining. Therefore, the ground is wet.'

Independent Support

When two premises independently support the same conclusion. Example: 'It is raining. It is cloudy. Therefore, it is likely to rain.'

Conjoint Support

When two or more premises work together to support a conclusion. Example: 'It is raining, and it is cloudy. Therefore, the ground is wet.'

Hidden Assumptions

Unstated beliefs that are necessary for an argument to hold. Example: 'Everyone should exercise.' (Assuming everyone values health.)

Ad Hominem

Attacking the person making the argument rather than the argument itself. Example: 'You can't trust John's opinion on climate change; he's not a scientist.'

Genetic Fallacy

Judging something based on its origin rather than its current meaning or context. Example: 'You shouldn't listen to that theory; it originated from a disreputable source.'

Straw Figure

Misrepresenting someone's argument to make it easier to attack. Example: 'People who support environmental regulations want to shut down all factories.'

Red Herring

Introducing irrelevant information to distract from the argument. Example: 'Why worry about climate change when there are so many homeless people?'

Appeal to Authority

Claiming something is true because an authority says so, without further evidence. Example: 'A famous actor believes in this diet; therefore, it must be good.'

Appeal to Force

Using threats to support an argument. Example: 'You should agree with my position; otherwise, you’ll lose your job.'

Appeal to Popularity

Claiming something is true because many people believe it. Example: 'Everyone believes in this conspiracy theory, so it must be true.'

Appeal to Consequences

Arguing that a belief is true or false based on the consequences of accepting it. Example: 'If we accept this theory, it means we must change our lifestyle, which is difficult.'

Equivocation

Using ambiguous language to mislead or misrepresent the truth. Example: 'A feather is light. What is light cannot be dark. Therefore, a feather cannot be dark.'

Appeal to Ignorance

Claiming something is true because it has not been proven false. Example: 'No one has proven that aliens don't exist, so they must exist.'

Slippery Slope

Arguing that a small first step will inevitably lead to a chain of related events. Example: 'If we allow students to redo tests, soon they will expect to redo every assignment.'

Texas Sharpshooter

Cherry-picking data to suit an argument while ignoring data that contradicts it. Example: 'This study shows that our product is the best, ignoring studies that show otherwise.'

Post Hoc

Assuming that because one event followed another, it was caused by it. Example: 'I wore my lucky socks, and we won the game. My socks caused the win.'

Hasty Generalization

Making a conclusion based on insufficient evidence. Example: 'My two friends from that city are rude; therefore, everyone from that city is rude.'

False Dilemma

Presenting two options as the only possibilities when more exist. Example: 'You either support this law, or you don't care about the environment.'

Begging the Question

Assuming the conclusion within the premises. Example: 'Freedom of speech is important because people should be able to speak freely.'

Burden of Proof Shifting

Placing the burden of proof on the wrong party. Example: 'You can't prove that ghosts don't exist, so they must be real.'