Chapter 1: Critical Thinking

critical thinking
judicious reasoning about what to believe and, therefore, what to do

Chapter 2: The Nature of Argument

argument
one or more premises leading to a conclusion

conclusion
some statement of fact or opinion that is supported by one or more premises

premise
evidence or reasons supporting a conclusion

circular argument (an error in reasoning)
an invalid argument in which the same point serves as both premise and conclusion; an argument in which one assumes to be true what one is trying to prove to be true

counterargument
an argument whose conclusion in some way counters that of another argument

burden of proof
the responsibility for providing proof for some claim

appeal to ignorance (an error in reasoning)
this error occurs when one concludes that a claim is true because there is no evidence that it is false

fact
a statement about the world as it is

opinion
a statement about the world as one thinks it is or should be or could be

deductive argument
an argument in which the conclusion makes explicit what's already implicitly contained in the premises, and the conclusion follows necessarily from the premises

inductive argument
an argument in which the conclusion goes beyond the information given in the premises, and the conclusion follows with some degree of probability from the premises

Chapter 3: The Structure of Argument

single convergent structure
an argument in which one premise leads to one conclusion

multiple-separate convergent structure
an argument in which two or more separate (independent) lines of reasoning lead to one conclusion

multiple-linked convergent structure
an argument in which two or more linked (dependent) lines of reasoning lead to one conclusion

divergent structure
an argument in which one line of reasoning leads to two or more conclusions

chain argument
an argument in which the conclusion of one argument becomes a premise of the next argument (and, possibly, so on)

multi-structured argument
an extended argument consisting of several sub-arguments of various structure

Chapter 4: Relevance

relevance
the truth of the premise makes a difference to the merit of the claim it is supposed to support

appeal to the person (ad hominem)
a response to the person making the argument (to the person's character, practices, or interests), rather than to the argument itself

genetic fallacy
a response to the origin (genesis) of an argument, rather than to the argument itself

appeal to inappropriate authority
an appeal to the judgment of someone who is neither relevantly qualified nor reliably accurate and unbiased 

appeal to tradition or past practice
an appeal to some tradition or past practice to support a claim

appeal to custom, habit, or common practice
an appeal to some custom, habit, or common practice to support a claim  

appeal to moderation (or lack of)
an appeal to the moderate or extreme nature of a position as support for that position

appeal to popularity (or lack of)
an appeal to the popularity of a position as support for that position (appeal to the majority) or to the lack of popularity as support for that position (appeal to the minority)

“two wrongs” fallacy
the suggestion that a particular action is acceptable if others are doing the same thing

paper tiger
this error occurs when a person responds to an argument that is not the argument that was presented, but is, usually, a simpler version or a more extreme version of the original argument

red herring
an irrelevant response usually intended as a distraction from the presented argument

non sequitur
any statement that doesn't follow from whatever it was it was presumed to have followed from

appeal to emotion
the use of an emotional response to a claim as reason to accept or reject said claim 

Chapter 5: Language

loaded language
language that is “loaded” with value judgments

genus and species
“genus” refers to the larger group to which a thing belongs and “species” refers to the features that set this particular thing apart from others in that larger group; useful for defining terms

necessary conditions
those conditions or attributes that are required (necessary) in order for something to fall within your definition

sufficient conditions
those conditions or attributes that if present are all that is required (sufficient) for something to fall within your definition 

inclusiveness
definitions that are too broad are too inclusive (they include more than you want)

exclusiveness
definitions that are too narrow are too exclusive (they exclude more than you want) 

equivocation
an error of reasoning that occurs when you use the same word to refer to different things in an argument

Chapter 6: Truth and Acceptability

truth
a claim is true if it accords with the facts (according to the correspondence theory)

acceptability
a claim is acceptable to the degree it is plausible (possible and reasonable), conforms to other claims known to be true, and has implications that are acceptable

verifiability
a claim is verifiable if one can describe conditions under which one can show it to be true

falsifiability
a claim is falsifiable if one can describe conditions under which one can show it to be false

subjectivism
a theory of truth proposing that something is true if you believe it's true

coherence theory of truth
a theory of truth proposing that something is true if it fits with other things we hold to be true

correspondence theory of truth
a theory of truth proposing that something is true if it accords with the way things are

innate ideas
a theory of knowledge proposing that we are born with certain ideas

empiricism
a theory of knowledge proposing that all of our ideas are obtained through experience

rationalism
a theory of knowledge proposing that one can know things without experience, by use of one's reason alone

absolute numbers
individual numbers such as one, two, three…

percentages
how many per hundred

mean
the number obtained by adding all the numbers and dividing by how many there are; often called “the average”

mode
the most often occurring number in a series

median
the number in the middle of a series (there are as many numbers above it as there are below it)

margin of error
the largest plausible difference between the given results of a study and reality

level of confidence
an indication of the likelihood that the given results do in fact reflect reality

either/or fallacy
the presentation of two options as if they're the only options when in fact they're not, and/or the presentation of two options as if one can't choose both or as if both can't be true when in fact one can or they can

fallacy of composition
an assumption that what is true for individual parts is necessarily true for of the whole formed by those parts

fallacy of division
an assumption that what is true of a whole is necessarily true of the individual parts that form that whole

gambler's fallacy
an assumption that previous occurrences affect probability of current occurrences

Chapter 7: Generalization, Analogy, and General Principle

sufficiency
the degree of support provided by the premises of an argument for its conclusion (also called adequacy); a premise or a series of premises is sufficient when their truth or acceptability and relevance make the conclusion more probable than alternative conclusions

generalization
a general claim about something based on specific evidence about that something; generalizations are usually based on quantities (also called induction by enumeration) or qualities

sample
the studied group of particulars from which a generalization is made

target population
the total group about which a generalization is made

self-selected sample
a group that includes only people who voluntarily come forward to be part of the study 

simple random sample
a group that includes only people selected at random

stratified random sample
a group that includes a random sample of representative size of each of the relevant categories

argument by analogy
an argument that involves reasoning from one situation to an analogous, or similar, situation: A has/is X, so B applies; C also has/is X, so B should also apply

argument by application of a general principle
an argument that involves reasoning from a general principle to a particular instance of that general principle: all A are subject to X; B is an A; so B is subject to X

overgeneralization
a generalization that goes beyond the evidence in terms of scope, frequency, or certainty

insufficient sample
a sample that is too small to justify the conclusion

unrepresentative sample
a sample that does not have the relevant features of the target population

weak analogy
an analogy in which few of the relevant features are similar

false analogy
an analogy in which none of the relevant features are similar (or they're dissimilar in the relevant aspects)

misapplied general principle
an error of reasoning that occurs when one applies a general principle to a particular instance to which the principle doesn't apply because of the absence or presence of certain critical qualities which disqualify or make the particular instance an exception to the rule

Chapter 8: Inductive Argument: Causal Reasoning

correlation
mere association, in time or space, not necessarily evidence of causation

causation
an association such that one thing is the reason or explanation for the other

direct cause
the cause closest in time to the final effect (also called the proximate cause)

indirect cause
a cause removed in time from the direct cause of an effect (also called a remote cause)

necessary cause
a condition that must be present for the effect-in-question to occur

sufficient cause
a condition which alone results in the effect-in-question 

Mill's method of agreement
this method of determining cause involves looking for the element that is in common in each case, the element that is always present when X happens 

Mill's method of difference
this method of determining cause involves looking for the element that makes a difference, the element that when taken out of the picture also seems to take out the effect

Mill's method of concomitant variation
this method of determining cause involves looking for the element that when changed, changes the effect

Mill's method of residues
this method of determining cause involves a process of elimination whereby one looks for the element which is left over when we have attributed several causes to several effects but one: the remaining effect is caused by the leftover element

mistaking correlation for causation
this error of reasoning occurs when one assumes that mere association in time and/or space implies causation

post hoc ergo propter hoc
this error of reasoning occurs when one assumes that because B happens after A, B is caused by A

failing to consider a common cause
this error of reasoning occurs when one fails to consider the possibility that some common thing, C, is causing both A and B (presumed to be in a causal relationship)

failing to consider additional causes
this error of reasoning occurs when one assumes that a partial or necessary cause is the complete or sufficient cause

reversing cause and effect
this error of reasoning occurs when one assumes or concludes that A causes B, when in fact B causes A

failing to consider a reciprocal causal relation
this error of reasoning occurs when one fails to consider that in addition to A causing B, B may be causing A

slippery slope
this error of reasoning involves presenting a chain argument in such a way as to suggest that the first step link in the chain makes the final outcome inevitable when, in fact, it does not

Categorical Logic

categorical logic
the logic of categories of things; also called predicate logic

predicate logic
see categorical logic

categorical statement
a statement indicating the relationship between categories; for example, “All A are B”

universal affirmative
a statement indicating the relationship between categories; for example, “All A are B”

particular affirmative
a categorical statement indicating that some As are Bs

universal negative
a categorical statement indicating that no As are Bs

particular negative
a categorical statement indicating that some As are Bs

logical equivalence
two statements such that either both are true or both are false

conversion
the statement that results when you reverse the subject and predicate of any given  statement

obversion
the statement that results when you negate the predicate and change the statement from affirmative to negative (or vice-versa)

contrapositive
the statement that results when you negate both the subject and predicate of a statement's converse

logical incompatibility
statements are logically incompatible when they can't both (or all) be true

logical compatibility
statements are logically compatible when they can both (or all) be true

contradictories
two statements that can't both be true, but can't both be false (one of them must be true)

contraries
two statements that cannot both be true, but could both be false

subcontraries
two statements that cannot both be false, but they could both be true

syllogism
an argument with two premises that together lead to a single conclusion

valid syllogism
if the premises necessarily imply the conclusion, the syllogism is valid

invalid syllogism
if the premises do not necessarily imply the conclusion, the syllogism is invalid

major premise
the premise that states the general principle

minor premise
the premise that presents the specific case in question

conclusion
some statement of fact or opinion that is supported by one or more premises

middle term
the term common to both premises

minor term
the subject of the conclusion

major term
the predicate of the conclusion

distributed term
any term in a categorical statement that tells us something about the entire category

fallacy of four terms
this occurs when a syllogism has four terms

fallacy of the undistributed middle
this occurs when the middle term of a syllogism is not distributed in at least one of the premises

illicit major
a major term that is distributed in the conclusion but not in its premise

illicit minor
a minor term that is distributed in the conclusion but not in its premise

fallacy of exclusive premises
this occurs when a syllogism has two negative premises

fallacy of drawing an affirmative conclusion from a negative premise
this occurs when a syllogism has a negative premise but an affirmative conclusion

existential fallacy
this occurs when both premises of a syllogism are universal and the conclusion is particular and all three categories in the syllogism do not have at least one member

Propositional Logic

conjunction
a proposition indicating that both p and q are true

disjunction
a proposition indicating that p or q is true (exclusive disjunct) or that p and/or q is true (inclusive disjunct) 

negation
a proposition indicating that p is not true

conditional
a proposition indicating that if p is true, then q is true

affirming the antecedent (modus ponens)
a valid argument having this form: if p, then q; p; Therefore, q

affirming the consequent
a invalid argument having this form: if p, then q; q; Therefore, p

denying the consequent (modus tollens)
a valid argument having this form: if p, then q; not-q; Therefore, not-p

denying the antecedent
an invalid argument having this form: if p, then q; not-p; Therefore, not-q

reductio ad absurdum
a valid argument having this form: p or not-p; assume p; if p, then q; q is absurd/false; Therefore, not-p

chain argument
a valid argument having this form (with an unlimited number of links): if p, then q; if q, then r; if r, then s; Therefore, if p, then s

disjunctive syllogism
a valid argument having this form: p or q; not-p; Therefore, q (or, alternatively, p or q; not-q; Therefore, p)

conjunctive syllogism
a valid argument having this form: not both p and q; p; Therefore, not-q (or, alternatively, not both p and q; q; Therefore, not-p)

constructive dilemma
a valid argument having this form: p or r; if p, then q; if r, then s; Therefore, q or s

destructive dilemma
a valid argument having this form: not-q or not-s; if p, then q; if r, then s; Therefore, not-p or not-r

Thinking Critically About Ethical Issues

ethics
the study of matters of right and wrong

morality
a particular system of ethical beliefs or principles 

values-based ethical reasoning
determining whether an action is right or wrong according to whether or not the action in question conforms to certain values

rights-based ethical reasoning
determining whether an action is right or wrong according to whose and which rights are upheld or violated by the act in question

consequence-based ethical reasoning
determining whether an action is right or wrong according to its consequences

hedonistic calculus
a method for determining which act produces the greatest good for the greatest number whereby each act is assigned a number of “hedons” according to the pleasure or pain it will bring about, measured by the intensity, duration, certainty, propinquity, fecundity, purity, and extent of said pleasure or pain 

is/ought fallacy
this error of reasoning occurs when one says that something ought to be the case because it is the case

arbitrary line fallacy
this error of reasoning occurs when one assumes that because a dividing line is arbitrary (there isn't really any difference between the points immediately on either side of the line), it's not a line worth drawing (it does not distinguish between any two points on the continuum)