Critical Thinking PDF

CRITICAL THINKING DEFINITION ★ Critical Thinking is the best antidote to fanaticism to social and environmental destruction and to simple private foolishness ★ 2 virtues of critical thinking ○ Humility - understanding that we don’t know everything ○ Critical thinker rai...

CRITICAL THINKING DEFINITION ★ Critical Thinking is the best antidote to fanaticism to social and environmental destruction and to simple private foolishness ★ 2 virtues of critical thinking ○ Humility - understanding that we don’t know everything ○ Critical thinker raises questions/inquisitive - does not stop asking questions ★ Critical thinking is the careful application of reason in the determination of whether a claim is true ★ Critical thinking is the evaluation of claims, however we come up with them CLAIMS ★ statements are the kinds of things that are either true or false ○ Whenever we call a claim into question (when we as questions about its truth or falsity) we raise an issue ○ Claims are the central focus of critical thinking ○ ISSUE: question whether a given claim is true or not/question that is raised ★ People have opinions, views, thoughts, beliefs, convictions, and ideas ○ All of these are claims ○ Statement, judgment, assertion, claim all mean the same thing ARGUMENT ★ A claim that is offered as a reason for believing another claim is a premise ★ The claim for which a premise is supposed to give a reason is the conclusion of the argument ★ A conclusion + at least one premise ○ The part of an argument that you try to support is called the conclusion ○ The part that does the supporting is the premise/s ○ How many premises can an argument have? - more than one KNOWLEDGE ★ To be entitled to say that you know the claim: (JTB ACCOUNT OF KNOWLEDGE) ○ There must be justification for the belief ○ You believe the claim is true ○ You have no reason to suspect that your belief is true ★ Evidentialism: W.K. Clifford ★ It is wrong always, everywhere, and for anyone, to belief anything upon insufficient evidence The wise person is the one who wishes to keep such errors to a minimum and who knows how to do it “Everyone is entitled to their opinion” - But critiquing another person’s is not equal to attacking the person (not a put down) VALUE JUDGMENT VALUE JUDGMENT ★ A term for a claim that expresses an evaluation of something ★ There are different varieties of value judgments because we evaluate things on different kinds of scales ○ We are constantly comparing one thing to another, and we are interested in what is valuable and what is not ★ Among our most important value judgments are those that assign moral or ethical values to objects and actions  ★ To claim that value judgments cant be challenged or defended because they are just substantiated opinions is a serious mistake ★ Somewhat different tastes and somewhat different experiences can lead us to different evaluations, and we don’t have generally accepted methods for setting differences ★ We have a generally accepted methods of setting an issue ★ People dress up what they say with rhetoric: language that has psychological force but carries no weight logically ★ Words can inflame passions and make it difficult to evaluate ideas on their merits. The emotional associations of words make an objective and neutral assessment of ideas difficult ★ There is nothing wrong with presenting your views in the best light (persuading ○ We must refine our ability to distinguish between the thought itself and the psychological packing in which it is given to us ○ Political advertising: images and rhetoric because it works EXAMPLES There is a lot of smoke in here because their is a fire out there (only presents a cause) There is a fire out there because there is a lot of smoke (claim, kase meron shang evidence) An argument attempts to support or prove a conclusion while an explanation specifies what caused something or how it works or what it is made out of and so forth X BECAUSE Y = can be an argument or cause/effect explanation She just finished working out because she is sweating (argument) She is sweating because she just finished working out (cause/effect) SUBJECTIVE JUDGMENT ★ True if you think it is true ★ Depends on what you think ★ OBJECTIVE JUDGMENT - Its truth is independent of what you think - Depends on objective fact ARGUMENTS ARGUMENTS ★ Has 2 parts ○ Conclusion: the position part “god exists” ○ Premise: The part that tries to support or prove it “something had to create the universe ★ THE LANGUAGE OF ARGUMENTS: ○ Conclusion indicators It follows that This shows that Thus Hence Consequently Accordingly So My conclusion is ○ Premise indicators Since For Because In view of This is implied by given ★ Often the conclusion of one argument is a premise in a second argument  ○The engine burns oil > therefore it will be expensive to fix > therefore we should buy a new car ★ Arguments can have an unstated premise ○ You aced the midterm; therefore you will pass the course Unstated assumption (premise): people who ace the midterm will pass the course ★ Conclusion may also be implied ○ You aced the midterm and people who aced the midterm will pass the course KINDS OF ARGUMENTS ★ Good deductive argument: ○ Is said to be valid if it isn’t possible for the premises to be true and the conclusion is false ○ Deduction indicator words Certainly Definitely Absolutely Conclusively It necessarily follows that It logically follows that It is logical to conclude that This logically implies that This entails that ★ Good inductive argument ○ Does not prove or demonstrate the conclusion, it supports it True premises raise the probability that the conclusion is true ★ An argument is valid if it isn’t possible for the premise to be true and the conclusion is false ★ VALIDITY AND SOUNDNESS ★ An argument is sound if it is valid and its premise are true INDUCTION ★ When we try to support a conclusion, we use induction. (when the premise doesn;t prove the conclusion) ★ The more likely the premise of an inductive argument makes the conclusion true, the stronger the argument ★ Many arguments contain no deduction or induction indicator words ★ Induction indicator words ○ Probably ○ Likely ○ It is plausible to suppose that chances are that ○ It is reasonable to assume that odds are that ○ One would expect that ○ It is a good bet that You are ten years older than jennie, therefore you will die before she does ★ Argument is valid ★ But the second premise is an unbelievably sweeping generalization Logic of proof: deduction Logic of support: induction Sweeping generalization turns inductive arguments into a valid deductive argument ★ That dog is a pit bull, it’s mean for sure ○ All pitbulls are mean ★ Mr. Parker is a democrat. After all, he teaches english ○ Anyone who teaches english is a democrat  DEDUCTIVE REASONING COMMON PATTERNS OF DEDUCTIVE REASONING ★ Hypothetical syllogism ○ Syllogism: two premise deductive argument ○ In a hypothetical syllogism, one of the premises is a conditional statement If it rains, the streets get wet. It rained, so the streets are wet If a, then b. A. therefore b. ○ This pattern is also called modus ponens One conditional premise An affirmation of the antecedent (IF) Affirmation of the consequent (THEN) ○ VARIETIES Modus ponens Chain argument Consists of three or more conditional statements that link together in the following way ○ If p then q > if q then r > therefore if p then r ○ If we don’t stop for gas soon, then we’ll run out of gas > if we run out of gas, then we’ll be late for the wedding ? therefore if we don’t stop for gas soon, we’ll be late for the wedding Modus tollens Denying the consequent Contains one conditional premise > a second premise that denies the consequent > a conclusion that denies the antecedent of the conditional If p, then q > not q > therefore not p Two patterns of hypothetical syllogism that are not logically reliable: the premises are true but the conclusion is false Denying the antecedent Affirming the consequent ★ Argument by elimination ○ This argument seeks to logically rule out various possibilities until only a single possibility remains Either Joe walked to the library or he drove > but Joe didn’t drive to the library > therefore joe walked to the library ★ Argument based on mathematics ○ Conclusion depends largely or entirely on some mathematical calculation or measurement Perhaps in conjunction with one or more nonmathematical premises Light travels at the rate of 186 000 miles per second > the sun is more than 93 million miles away from the earth > therefore the sun’s light takes more than eight minutes to reach the earth ★ Argument from definition ○ The conclusion is presented as being true by definition, that is following simply from the meaning of some keyword or phrase used in the argument Bachelors are unmarried men > jose is an unmarried man > so jose is a bachelor Propositional logic ★ Logic is at the core of computers and everything they do ★ The kind of reasoning: if then not and or - is logic and its what ensures computers know what to and when based on whether statements are true or false ★ Propositional logic deals with propositions or sentences that can be either true or false ○ True: if the robot in question is blue ○ False: if the robot is some other color Truth table  ★ Lists all possible combinations of values for the logical variables in a formula and what that means for whether the formula is true or false CATEGORICAL LOGIC CATEGORICAL LOGIC ★ Studies the relations among classes or categories or things ★ CATEGORICAL CLAIMS: make assertions about classes/group of things ○ Make up the subject matter of categorical logic ★ NEEDS NOUNS ○ Predicate often has an adjective All kittens are adorable > all kittens are adorable animals Some logic lessons are exciting > some logic lessons are exciting lessons ★ Standard form of categorical claims ○ A: All _ (subject)are___ (predicate) ○ E: No_are_ ○ I: Some_are_ ○ O: Some_are not_ S and p are nouns and noun phrases called terms ★ Categorical logic begins with the task of translating claims into standard-form categorical claims ○ Claims about whole classes require only the addition or substitution of words like all and no Each student is a responsible adult > all students are responsible adults Claims that translate into one another in this way are called equivalent claims ○ Claims in the past tense are turned into the present tense that characterizes standard-form categorical claims Some conspirators were protestants > some of the people who were conspirators are people who were protestants ○ Ordinary claims containing ONLY become A claims Identify subject and predicate terms correctly Only by itse;f comes before the predicate Only adults are legal drivers > all legal drivers are adults The only comes before the subject The only good cars are japanese cars > all good cars are japanese ○ Many claims speak generally about times and places and we need to make the references to time and place explicit I'm loved wherever i go > all places i go are places im loved ○ Claims about single individuals need rephrasing before they can count as categorical claims (becomes a or e claims) We replace the single thing’s name N with the phrase: All things (people places and so on) are identical with N Cleveland has the best orchestra in the country > all cities identical with cleveland are cities that have the best orchestra in the country ○ Claims that use mass nouns (general nouns) are best translated with a phrase about examples of that stuff Water is colorless ? all examples of water are examples of something colorless (A claim) SQUARE OF OPPOSITION ★ A and E claims are contrary claims: never both true ○ If all rooms are vacant (T) No rooms are vacant (F) ★ I and O are subcontrary claims: can never both be false ★ A and o claims are contradictory claims, as are corresponding e and i claims: they have opposite truth values CATEGORICAL SYLLOGISMS ★ A syllogism is a 2 premise deductive argument ★ A categorical syllogism in standard form is a syllogism whose every claim is a standard form categorical claim and in which 3 terms each occur exactly twice in exactly 2 of the claims ○ P1: All americans are consumers P2: Some consumers are not democrats Therefore some americans are not democrats Three terms: AMERICANS, CONSUMERS, AND DEMOCRATS ○ Major term P: predicate term of the syllogism’s conclusion ○ Minor term S: subject term of the syllogism’s conclusion ○ Middle term: term that appears in both premises of the argument but not in the conclusion In standard form categorical syllogism, the major premise goes on top of the minor premise (middle) ○ Some consumers are not democrats > all americans are consumers > therefore some americans are not democrats ★ Categorical syllogisms with unstated premises RULES FOR TESTING THE VALIDITY OF CATEGORICAL SYLLOGISMS ★ KAY SIR ○ RULE 1: The number of negative claims in the premises must be the same as the number of negative claims in the conclusion Negative premise, affirmative conclusion No valid syllogism has two negative premises ○ RULE 2: At least one premise must distribute the middle term ○ RULE 3: Any term that is distributed in the conclusion of the syllogism bust be distributed in its premises ★ FACULTY FIU ○ RULE 1: middle term must be distributed in at least one premise ○ RULE 2: any term that is distributed in the conclusion must be distribut