CTRW 1

Serial Reasoning

"He has lots of money for he won the lottery. So he can afford a house." He won the lottery -> he has lots of money (intermediate conclusion) -> thus he can afford a house. (C) 2: Since it's raining, the streets are wet. So the roads must be slippery. It's raining-> the streets are wet -> roads must be slippery. 3. "The building is about to collapse and so we should evacuate now. Its foundations are weak, because its foundations have been damaged by the flood. Been damaged by flood -> foundations are weak -> Building is about to collapse -> we should evacuate now. Note: the part where the foundation is weak to building about to collapse needs to be inferred.

Convergent argument

"He'll be late because he left late. There's also a bad traffic jam." He left late -> He'll be late. There's a bad traffic jam. -> He'll be late. Note: both reasonings are independent of each other. To be independent, the reasonings are independent if and only if its support of the conclusion is insensitive to the truth or falsity of the other reasons. 2. "Beijing must be north of Shanghai because it has the greater latitude. Moreover, it's colder there in the winter. Beijing has the greater latitude. -> Beijing is North of Shanghai. Beijing is colder there in the winter. -> Beijing is North of Shanghai. 3. "Studying for the test is pointless since the test is not graded. Besides, it's easy to cheat on the test. Test is not graded It's easy to cheat on the test -> Studying for the test is pointless.

Conditional statements

"If" is not a reason indicator And never break up a conditional statement the If statement can either serve as a reason or conclusion.

Is there an argument?

"Snakes are dangerous because they slither around and make strange hissing sounds." This is not an argument as the reasonings are not strong enough. 2. "If teaching is such an attractive job, why is there a shortage of teachers?"

Combination reasonings

"The crisis in the Middle East is hard to solve (1) because the Palestinians and the Israelis are both to blame. (2)The Palestinians are unjustified in seeking the destruction of Israel. (3) Then again, the Israelis keep building settlements on Palestinian land in violation of Security Council resolutions." (4) 3+4 -> 2 -> 1 Note: the keyword "both" is required, and so it requires two factors (Linked reasoning ) to acquire immediate conclusion. "Since the rat is still alive (1), it appears that it did not eat the apple. (2) For if it had, it would not still be alive, (3) because the apple was poisoned." (4) 3: If the rat ate the apple, it would not still be alive. (4 -> 3) , 3(intermediate conclusion) + 1(basic premise) - > 2 Note: within the intermediate sections, note of the conclusion and reasonings to support the final conclusion. But within 3, it is not sufficient to say why the rat didn't eat the apple. It has to be supported with being still alive.

Divergent reasoning

"The residents will suffer since the noise is unbearable. The birds will be frightened off too. The noise is unbearable -> the residents will suffer -> the birds will be frightened off. "My father is a fireman, so obviously he is brave and he puts out fires." My father is a fireman. -> He is brave -> He puts out fire.

Assessing probabilities

0.1% = 1/1000 5% = 50/1000 (same denominator) and read qns carefully (don't be lazy and afraid) 1/51 x 100%= 2%

Implicit 2

1. "Either my hard disk collapsed or my PC has a virus. But my hard disk is new and a new hard disk is unlikely to collapse. So my PC must have a virus." My hard disk is new and a hard disk is unlikely to collapse. -> My hard disk did not collapse. + Either my hard disk collapsed or my PC must have a virus -> My PC has a virus. Note: Usually statements with "if" or "either" needs to pair up with another statement to answer the question to prove a point. (Linked reasoning) For this either statement, there's not a need to be backed up by another reasoning because it's not something that need to be asked why. Steps: (grayling argument) 1. identify your conclusion so you know what your reasonings are. 2. Ask yourself why did you say the either statement 2. "Either" or "if" + 1 statement to assert that something is done 3. That 1 statement is beef up by triangle

Linked reason arguments

1. "Elephants have no teeth, for they don't bite, whereas they would if they had teeth." If elephants had teeth, they would bite + elephants don't bite = elephants have no teeth. Note: if statement can also be a reasoning Both reasonings are dependent of each other to arrive at the conclusion. If only use 1 reasoning doesn't make sense. For: it's a reasoning indicator 2. All men are mortal + Socrates is a man = Socrates is mortal. "It's 4pm over here, so it must be 9am in London. This is because we're seven hours ahead of London." It's 4pm over here + We're seven hours ahead of London. -> It's 9am in London. 3. It will either rain or snow. So the match will definitely be cancelled, since it will be cancelled if it rains, and it will be cancelled if it snows. It will either rain or snow + it will be cancelled if it rains + it will be cancelled if it snows -> so the match will definitely be cancelled. Note: the conditional statement was supposed to be 1 but it can be split into two parts because it's talking about two different things.

Inference v premise

1. False premise, but good inference ( not good argument) All men sing in the bathroom X + PM Lee is a man (tick) -> Pm Lee Sings in the bathroom 2. Both premises false, but good inference Smoking is good for your health X + Things that are good for your health should be banned X -> Smoking should be banned. 3. Both premise true, but bad inference Japan is larger than Singapore + South Korea is larger than Singapore -> Japan is larger than South Korea X (Both premises are good, but doesn't support the conclusion) 4. Both premises true, but inference is bad If it's a Christmas Day, it's a public holiday. -> If it's a public holiday, it's Christmas day. X 5. premise false Premises come in true or false Inference: Valid 100%, strong 70-99% , moderate 50-70 , weak 1-49, no support (degree)

Criteria for evaluating explanations

1. Predictive power 2. Enhanced control 3. Simplicity 4. Coherence with other beliefs Predictive power: prediction that is supported by experience would be more strongly supported. Enhanced control: Some explanations enhanced our power to control events (smallpox explained in terms of viral infection but not to God's wrath is a better argument) Limitations: Some plausible explanations do not allow us to predict and control events (a plausible explanation of the Russian Revolution may not make any concrete predictions about future events.) but might still be a good explanation Simplicity: A simple explanation is most likely to be true and a better argument. Coherence with other beliefs: if you live in a society with a lot of corruption and your neighbour got very rich, it is more plausible and a better argument to think he has done sth corrupt. But if he doesn't live in a corrupt society, your argument is weaken. Coherence limitation: we shouldn't assume that our background beliefs are justified.

criteria of good definition

1. clear 2. as precise as possible 3. not too broad 4. not too narrow 5. non-circular 6. not unfairly emotive Clarity: 1. Poor grammar 2. Poetic or metaphorical language (eg. jewel) 3. use of terms in the definiens that are obscure (complex vocabs) 4. Ambiguity or double (or even triple) meaning (eg. adultery is having sex with someone with a spouse Vagueness (lack of precision): eg There was a heap of sand in the road. (But how many grains make a heap?) (if it's still unpackable, then it is still imprecise) not too broad: the definition is too broad, meaning the definiens includes what does not belong to the definiendum eg. a typewriter is a means of writing (too broad) not too narrow: the definition is too narrow that the definiens excludes what belong to the definiendum eg. a bird is a feathered animal capable of flight (too specific) (penguins) special: a cup is a container for liquids. (it can be too narrow and too broad) lighthouse: too narrow, too broad (a tall building with a light) prime no. (if and only if) Non-circular: a definition is circular if knowledge of the term being defined is assumed in the defined phase. eg. a triangle is a plane figure with a triangular shape. eg. A true statement is a statement that is not false. (if you know true statement, you would also know what is a false statement.) To check if it's circular, we need to answer it one way and then rotate it the other way. Definition: If an only if the definiens presume an understanding of the meaning of the term being defined. Not unfairly emotive: Statement 1: Corporal punishment is the infliction of pain upon offenders Statement 2: Corporal punishment is the barbaric torture of human beings to satisfy a lust for revenge (aim to invoke emotions as well) Thus it's unfair to use the second definition) Don't just think of its separate issue. Think of what could be improved. If translate to other language, you are forced to decide a specific word.

Sample size

100, 1000 => a sample of at least 10% is recorded.

1.7 2

34. Stanley and Wise insist that, above all else, feminists have a moral and political responsibility to resist any imposition of the reality or standpoint of one person on others or any privileging of one perspective over another My teacher, holding up a bucket, said: "Let me demonstrate the principle by means of logic. If this bucket has a hole in it, then it will leak. But it doesn't leak. Therefore, obviously it doesn't have a hole in it." (Comment. Tricky! The author, namely the student, has given a report of his teacher's reasoning, but his report is not itself a piece of reasoning.) The Green Movement is mistaken in thinking we should recycle materials like paper and glass because paper and glass come from easily renewable and commonly available resources, such as trees and sand. Furthermore, in some American cities recycling schemes have been abandoned because they are too expensive. The materials of nature (air, earth, water) that remain untouched by human effort belong to no one and are not property. It follows that a thing can become someone's private property only if he works and labours on it to change its natural state. The orbit of the moon, being lower than that of the sun, determines eclipses.

Summary so far

4 types of if long if two types of either

a good argument

A good argument must possess acceptable premises and acceptable inference.

Causal Argument

Basic form: 1. A is correlated with B 2. The best explanation of the correlation is that A causes B therefore -> A causes B Example: 1. Smoking tobacco is correlated with lung cancer 2. The best explanation of the correlation is that smoking causes lung cancer. therefore -> smoking causes lung cancer They are abductive: We do elimination method to conclude A causes B is more plausible. Observe multiple incidences to eliminate coincidence. However, for historical events we can't do repetitions of many events (russian revolution 1964) -> thus we generalize. For eg, stock mkt crash 1929-> economic depressions Evidence against B causes A Effect cannot precede A. To find if B causes A, see if A occurs before B. However, other cases. Insomnia and high stress levels Optimism and happiness (Which one came first??) Cycle of causation: feedback cycle going: low income -> lesser educational opportunities (A causes B and B causes A) Evidence for/against a third cause To rule out a third cause is examining various possible third causes and showing that they are implausible. (eg. showing they are correlated with A and B, or occur after A and B) Limitation is difficult to be exhaustive. (There may be possible third causes and hence didn't test) More hour study -> higher exam score Unlikely it's the other way round, it's not a coincidence. Lemon , high way accidents A -> B B -> A (nope) Third factor -> maybe there's a new system of importing Fourth factor -> more likely Shark attack , ice cream sales Third factor: summer (eat a lot of ice cream, and swim the sea) Average temperature , pirates industrialization: third factor -> no need to resort to piracy Rigorous way of testing for causation Controlled studies: Active selection. RCT But it could be psychological effects, placebo Blind studies: drug trial (test and control group) Make both groups don't know if they are control or treatment group. Blind studies are often not possible as in terms of meditation, you cannot fool people into thinking that they are (or are not) practicing meditation. Active selection: 1. impossible, the target property is not something we can control (being tall makes you more confident) 2. impractical, because too expensive 3. immoral (smoking cause lung cancer) practice qns: 1. coffee: can be blind study 2. go smu, pretend to be nus (cannot blind study) 3. funny and sexually attractive (subjective)

Argument from authority

Because we don't know everything. Check with the expert car check - car mechanics S said that P is true S is an authority on the subject. Therefore P is true Google map, WHO, safety inspector, court (but the guilty may be framed), film critic (subjective), grandma (not a good argument) 1. Is this a topic where expertise is really possible? 2. is the cited authority a genuine authority on this topic? 3. is there a consensus among the relevant authorities? 4. Does the authority have any biases related to the claim they affirm that make them untrustworthy? We must take responsibility for our own beliefs and be willing to consider direct evidence and arguments rather than just relying on the conclusion of others. We must accept limitations and realize that much of out knowledge relies on the testimony and expertise of others. Argument from Analogies Illustrative analogies: attempt to explain a difficult, obscure or unfamiliar idea by relating it to something familiar, easier to understand, and less mysterious. But they not arguments. (atoms and planets obit the sun) Argument from Analogy: (car and lawnmower) 1. a is relevantly similar to b. 2. a has feature F therefore: B will have feature F. The more relevant, the stronger the argument. The similarities must be relevant to one another, then it would make more sense. Relevance is hard to define, but relies on the shared properties that are likely to play a role in the occurrence of the target property. New information can weaken the analogy argument: disanalogies. Lawnmower is electronic and car is combustion engine. Analogy argument doesn't work We need to think of dis-analogies to argue against. Moral reasoning: take a special deductive form and some arguments are morally significant.

Reason indicators

Because, since, as, for, owing to the fact that A because of B (A is conclusion, B is reason)

Falsifying Conditionals (cards)

Conditions and statements are different: (to prove the claim false) Conditions "if a card has an A on one side, it has 2 on the other." Statement: Cards have number on one side and letters on the other. A, K, 2, 7 (cards have numbers on one side, and letters on the other) "If a card has A on one side, then it has 2 on the other" is not equivalent to "If a card has 2 on one side, then it has A on the other" (introduce new "if") "Because if 7 has an A on other side, the claim "if a card has A on one side then it has 2 on the other" will be false.

Dilemma (valid)

Constructive if p then r if q then s Either p or q therefore -> r or s Destructive if p then r if q then s Either not-r or not-s therefore -> not-p or not-q p= it rains q= it snows r= the match will be cancelled s= the match will be delayed order doesn't matter.

True or false

Deduction: A valid argument may have false premises (True) An invalid argument may have true premises (True) A sound argument may be invalid (False) (it must be valid) A sound argument may have false premises. (False) (It has actually got true premises) Sound argument may have false conclusion (it has true premises and valid inference, the conclusion must be true.) An unsound argument may have a true conclusion. (True. and by coincidence) Induction: A strong argument may have false premises. (True, it's about the inference.) A weak argument may have true premises. (True, it's about the inference.) A cogent argument may be weak. (False. The argument A cogent argument may have false premises. (False. As it must have actual true premises.) A cogent argument may have a false conclusion. (True. It's about inductive argument and we can never guarantee the conclusion of an inductive argument.) Cogent argument probably has true conclusion. (It Strong argument with true premises probably has a true conclusion. (false. Three criteria: true premises, reliability) Uncogent arugment may have true conclusion. (it may be just by coincidence)

Dictionaries

Do not trust dictionaries completely Larger dictionary is better than small ones and specialised may be better experts argue about the meaning of the term

Disjunctive Syllogism (valid)

Either P or Q Not P Therefore Q Valid, regardless of whether the disjunction is inclusive or exclusive Either q or p Not q Therefore P You can object argument, but it will always be to the premise not the inference.

False dichotomy

Either p or q (disjunction) p therefore: not p Either p or q q therefore: not q (exclusive disjunction)= they are exclusive to be valid Either p or q, and not both bb Either p or q, and possibly both =p and /or q (inclusive) If it's inclusive, the argument would be in valid. It is unclear whether the disjunction is exclusive or inclusive, assume that it is inclusive.

some equivalences

If one of the statement is true, the other one would be false. A: All S are P (X) <=> O: Some S are not P I: Some S are P <=> E: No S is P Only S are P = All P are S All S are non-p = No S are P Not all S are P = Some S are not P All non-P are non-S = All S are P

hypothetical syllogism (flow)

If p, then q. If q, then r. Therefore, if p, then r. (Valid) Napolean example: fallacy of denying the antecedent

Abductive Argument

Is one in which the conclusion is the "best guess" that is judged to be the most plausible explanation among competing alternatives, given that the premise is true "inference to the best guess" Sherlock Holmes is assuming his arguments are better. The marks on Mr Wilson's jacket. Also there's no guarantee that is better. FIRST: we need to accept that one statement is true but you are unsure about the truth of a second statement. The abduction gives us grounds for accepting the second statement by showing us that it provides us the best explanation of the first statement. Abductive Must: People use the word "must", but it's actually inductive argument.

Exercise 1.7

No reasoning: "3. All of life's problems stem from a single issue and that issue is our relation to our own mortality, which we must face whatever else happens." "5. If, at any point in time, it is proven beyond any doubt that human beings are essentially no different from animals, especially mammals, maybe then we will rethink our treatment of these creatures." (author is not claiming they are the same, but just saying "if ..then"" 11. Nostradamus was a devout student of pagan methods of divination at night, who wore the mask of a devout Catholic during the day to avoid persecution from the Spanish Inquisition. In the end he predicted his own death, and some say he also cursed the marauders from the French Revolution that he foresaw would desecrate his own burial tomb. If camping were permitted on the beach, it would follow that hordes of people would stay over the weekend and that would lead to more pollution and crime. (same if..then) Challenging "6. The fantastic achievement of the Jamaican bobsled team, which against all the odds managed to finish their race without problems and even set a new Jamaican record in the process, supports the idea that not only traditional Winter Olympic nations can succeed in these games. So we must promote more equatorial nations to join the Winter Olympics." -> rephrase as (1) The Jamaican bobsled team had a fantastic achievement by finishing their race without problems against all the odds, even setting a new Jamaican record in the process. So (2) not only traditional Winter Olympic nations can succeed in these games. So (3) we must promote more equatorial nations to join the Winter Olympics. 8. Some say that those without strong religious beliefs (non-believers in one form or another) cannot be moral. Nevertheless millions upon millions of people have been non-believers or non-theists and yet have produced some of the most noble and most morally principled civilizations in history. (Implicit argument) Millions upon millions of people have been non-believers or non-theists and yet have produced some of the most noble and most morally principled civilizations in history. Therefore, those without strong religious beliefs can be moral. "Dropping out of school and bearing children outside of marriage are two of the primary causes of poverty in this country. Therefore, to eliminate poverty we must offer incentives for people to get high school diplomas. Also, we must find some way to encourage people to get married before they start having children.Comment. Two main conclusions based on one reason." (1) Don't copy off Stacey's exam. (2) She's one of the worst students in this class. (3) My other classmates told me she's failed every test last semester. (You can rewrite (1) to You should not copy off Stacey's exam.) Since the agreement was that you would clean the kitchen and I would clean the bathroom, I have to ask you to live up to it, for breaking an agreement is wrong. Furthermore, I kept my side of the deal. On the night of 14 April 1912, during the Titanic's maiden voyage, she hit an iceberg and sank two hours and forty minutes later, early on 15 April 1912. The sinking resulted in the deaths of 1,517 people, making it one of the most deadly peacetime maritime disasters in history. The high casualty rate was due in part to the fact that, although complying with the regulations of the time, the ship did not carry enough lifeboats for everyone aboard. First, I have noticed how you always wear shorts, even on chilly days. Second, none of your hobbies have anything to do with indoor activities. And finally, whenever I see you you want to go outside. For these reasons I believe that you are not suited for a 9-5 desk job, as it would drive you mad.Comment. "It would drive you mad" is an intermediate conclusion.

Online exercise 1.3

No reasoning: "Mary took offence at what you said and John just laughed "While it is certainly the case that Barbara is the better student, it must be acknowledged that Jane is much better at asking questions." "Notwithstanding the fact that I have yet to see one, I still believe in UFOs." "Rosie will not eat her pudding unless Richard feeds her with her special spoon." "The proposition that everyone has rights and responsibilities implies that you too have rights and responsibilities." (Just a proposition) "The hypothesis that the elderly should benefit more from the hard work they put in to help the nation become what it is today implies that the younger generation will have to pay more taxes." (hypothesis) "When the judge ruled that the defendant was innocent, I think he did so out of pity. There is nothing in the law preventing him from giving such a judgement." "If we accept that people are all equal, we must accordingly accept that all people have similar rights." (maybe because of "if") Challenging: "I know that in the short run cheating seems more beneficial. Nonetheless you should stop it because in the long run it will harm your career." (C: You should stop it" , I: Nonetheless" ) "The fact that there is a footprint in the garden bed below the window proves that Julia was not imagining things when she said that someone was looking in at us last night." "Unless Kate decides to visit Jack tonight, he will go to the pub because he is lonely." "Cricket is one of the most boring sports to watch. Accordingly, I always fall asleep when there's a match on TV as I can't manage to keep my eyes open." "Lewis and Thomas, stop arguing over what game to play! Since you will have to play together, Lewis will decide on the first game and then Thomas decides the next one." "There is a widely held belief that there is no God because we can't find any evidence for God's existence. To me this only proves that the idea of God is beyond humanity's scientific comprehension." "Based on the overwhelming evidence supporting the theory of evolution, I must say that I find those who still think the earth is flat a bit out of touch with reality." "This report clearly shows how dangerous it can be to go diving without proper equipment." "As the movie was finished, I suggested that we should go out for drinks, yet nobody was interested." "People should help each other whenever they can. This implies that you too should help by giving some of your money to the needy." "Seeing how Dan is never at home he might as well move to a smaller apartment." "Eat, drink and be merry for the end is nigh." Accordingly: CONCLUSIVE INDICATOR

the natural argument

Not wearing clothes is natural (next) If a thing should be done just because it is natural, then we should not wear clothes. + ( we should wear clothes) (assumption) (next) Just because something is natural does not mean we should do it,

Argument Structure + principle of charity

Separate the reasoning and conclusion Interpret someone's words in as sensible a way as possible while being careful not to put unintended words into his/her mouth.

Indicators

Since : reason - but there are times where it's not - for eg, since 4pm (it can be used for time factor) So: conclusion indicator For: reason indicator As shown by: reason indicator Consequently: conclusion indicator Unless: Neither Because: reason indicator Implies that: conclusion indicator Accordingly: conclusion indicator But: Neither While: Neither As: Reason indicator As demonstrated by: Reason indicator Notwithstanding: Neither (in spite of) Undoubtedly: Neither Approximately: Neither Proves that: Conclusion indicator In view of the fact that: Reason indicator Strongly suggests that: Conclusion Indicator With regards to: Neither Moreover: Neither Hence: Conclusion indicator Seeing that: Reason indicator Therefore: Conclusion indicator However: Neither Yet: Neither Nonetheless: Neither Thus: Conclusion indicator Is strongly suggested by: Reason indicator I think that: Neither

Counterexamples help

Some bus drivers are skinny Some taxi drivers are skinny Some bus drivers are taxi drivers (Premises true -> inference bad) Counter example: Some men are evil Some cats are evil -> Some men are cats

necessary vs sufficient (?)

Sufficient: if Necessary: only if You will feel pain if you have a toothache. You will feel pain only if you have a toothache. X A toothache is sufficient for pain but not necessary. You're a bachelor if you're a man. X You're a bachelor only if you're a man. Being a man is necessary for being a bachelor but not sufficient. Necessary and sufficient: A person is a bachelor if and only if he is a man and unmarried. Necessary and sufficient Stipulation: invent on own terms, meaning of term will be stipulative 1. Very occasionally, it is useful to invent our own terms 2. The meaning of a term will be stipulated and such definitions are stipulative. eg. to love someone: to die for someone

grayling argument

The conclusion has not been established.

Argument construction

Think of it whether it's inductive or deductive. Brainstorm (look for basic premises) Be prepared to modify your arguments. eg. refugees are innocent (some is not true) Singapore should take in refugees. (why? sg govt or as a society?) We need to have mutliple forms: convergent etc. Make sure you follow the rules that we follow. List premises - intermediate conclusion (got through categorical syllogism, or by modus ponen inference just needs to valid or inductive and you have to defend it. use valid deduction and strong induction.

Definition of circularity provided in textbook

Too narrow: For example, A true statement is a statement that is not false. Too broad: Some definition can be non-circular even if the definiens contain part of the term being defined. For example, "An Australian Cattle Dog is a highly trainable and loyal breed of dog originally bred in Australia for the purpose of herding cattle."

overview: Argument structure

Two one-premise arguments (convergent) One two-premise argument (Linked) Reasoning: Convergent Linked Serial Divergent Combinations Implicit inference indicator, implicit premise, implicit conclusion, implicit immediate conclusion Is there an argument? Think of the author's intention to see if it's linked or convergent reasoning basing on the linkage of reasonings.

Implicit

We have to assume stuff now. 1. "The police are here. We'd better run." But we need to interpret it to be -> "The police are here. So we'd better run." 2. "If you touch that, it will explode. So you should not touch it." If you touch that, it will explode + you don't want it to explode. -> You should not touch it. Note: you must answer if you want it to explode. (implicit inference) Touch, explode, you (complete triangle) 3. "Socrates will die one day. Such is the fate of all men." All men will die. + Socrates is a man -> Socrates will die one day. 4. "Just because something is natural it does not mean that we should do it, else we should not wear clothes. Not wearing clothes is natural -> If a thing should be done just because it's natural, then we should not wear clothes. + We should wear clothes -> Just because something is natural, it does not mean that we should do it. 5. The bigger the burger the better, and Burger King's burgers are the biggest. (triangle) Implicit conclusion: Burger king burgers are the best. Bigger the burger the better + Burger King's burgers are the biggest -> Burger king burgers are the best.

lessons for cny

When attacking the inference, assume the reasons are true. They are compatible, it can be true at the same time. There can be no successful attack upon a valid inference. (It's impossible) Even if the premises are true, this is still inductive reasoning. Mona is Singaporean, Most Singaporeans are Chinese > Mona is Chinese New information can weaken inductive reasoning but not deductive reasoning. If any new information doesn't attack the reasoning, it usually attack the inference.

Implicit premises

[implicit premises] How to tell what assumptions to include? 1. you have to believe it. 2. it is obvious 3. or very commonly believed? Does the author need it? Is the author aware of it? We can make any argument valid by adding premises. This is useful because it allows to see what assumptions and premises are at work. We can then decide whether these are true. Eg. You can see right through that door as it's made of glass. Missing premise (to make inference valid): You can see through glass. Eg. This can't be a spider because it doesn't have eight legs. Missing premise (needed to make the inference valid)" All spiders have eight legs. eg. Torturing animals for fun is wrong. That man is torturing that cat for fun. So what that man is doing is wrong. Missing premise: cats are animals Eg. All firemen are gentlemen; so he's a gentleman, since he's a fireman. Missing premise: none Jack is undoubtedly at the stadium now because nothing can stop a football fanatic from being at the stadium when a football match is being held there. Missing Premise: Jack is a football fanatic A football match is being held at the stadium now. It's no use worrying about contracting Hodgkin's disease because you will have no control over whether you will contract it. Missing premise: it's no use worrying about something you have no control over it. Jack is in town, since Jill is in town, and Jack is always with Jill. None. (already valid) He was born in Rom. So he was not born in China. Missing premises: Rome is not in China. You can't be born in two different places. You need to think about what to include and what you can safely leave out of your argument.

fallacy of hasty generalization

a generalisation based on a sample that is too small/ biased (unrepresentative of the whole) to support it Practice qns: 1. London taxi (fallacy of hasty generalisation: small sample size) 2. so.. it might be bias 3. weekends is different from weekdays. it's bias, even though it may not be. self selection is affected too. 4. bias. are the countries randomly selected? 5. it didn't say how well it does over the last few years as some of the companies may just exist or didnt exist already.

Forms of strong induction II

causal arguments Earthquakes are caused by the movements of tectonic plates Najib lost the Malaysian election because the people became sick of his corruption Being laughed at makes me embarrased. causes, became, makes General: Event A -> Event B heating a metal causes it to expand Particular: introducing prohibition in 1920 caused organised crime to increase Multi-factor causation: What caused the global financial crisis? 1. collapse of US housing market 2. high default rate in the home mortgage sector 3. Low interest rates Monolithic Cause Fallacy - Do not make the mistake of assuming that there is always one dominant cause (all factors could be right) Correlation Starting point is Correlation If they tend to occur together, the two events A and B occur regularly. From Correlation to Causation: 4 possible explanations for correlations 1. A causes B 2. B causes A 3. C (a third factor) causes both A and B 4. The correlation is a coincidence good causal argument: claim that A causes B must show that it explains the observed correlation better than the alternatives. A given event: A: group of peers attend univeristy B: they are more open minded 1. A- B 2. B - A 3. C (Smart) - B&A 4. uni students in group happen to be more open-minded. (coincidence) Correlation/causation fallacy: determining something causes something without considering or producing evidence

categorical syllogism

compare different category with each other Categorical statements: Universal statement A : All F are G. (Affirmative) E: No F are G (N) Particular statement I: Some F are G (A) O: Some F are not G (Negative) Some= stands for "at least one" but not all Only the conclusion where their positions are fixed. 1. All S are M (Valid) All M are P All S are P. 2. All S are M (Invalid) All P are M All S are P. (Dogs are whales?) 3. All M are P (Valid) Some M are S Some S are P. (Pirates and hairy people) 4. No M are P (valid) Some S are M Some S are not P (criminals and lawyers) 5. All P are M (invalid) Some S are M Some S are P (same as 2) 6. Some S are M (invalid) Some M are P Some S are P (some version is invalid)

definiens

definition

seminar 4

dotted lines means attack (to either conclusion, premise or inference) dotted lines can also be formed into an argument (eg. Albert is severely autistic ---> Albert is running a food stall. Albert is severely autistic ---> Albert is not running a food stall) (4) for every rich hawker stall operator, there are 3 poor ones. ---> (inference): it does not follow that Albert is rich just because he operates a hawker stall and many such operators are rich. Albert doesnt have have a driver license --> albert drives a taxi For every wealthy taxi driver, there are two poor ones ---> inference valid invalid inference: strong, moderate, weak, none so look at the argument and see if it's mutually exclusive with the premise, conclusion and inference. If it is, it doesn't weaken. The discovery of new information can often weaken the reliability of an inductive inference. (From moderately strong -> less strong) If it has valid argument, we cannot attack the inference. A good deductive argument must have true premises and a valid inference. This is a sound deductive argument and so it has a true conclusion. A good inductive argument must have true premises and a strong inference and be reliable (3) (don't leave out extra information) All cogent arguments have true conclusions Induction a) If a supporting argument is cogent, we say that the conclusion will likely be true. a)If an attacking argument is cogent, we should then say that the statement under attack will likely be false, or the inference under attack will be weak. Deduction a)If a supporting argument is sound, we say that the conclusion must also be true. b)If an attacking argument is sound, we should then say that the statement under attack must be false, or the inference under attack must be invalid. A good critical thinker will examine her arguments looking for attacking reasons that might undermine them. When she finds a strong attack she will either revise her argument, or change her position if no good revisions are available.

Genus vs Species

genus is more general: Ursus species is more specific: Ursus actors they are one level apart. This determines if it's too narrow or broad, case by case. A 'cat' is the species of the genus "feline mammal", the difference being 'unable to roar'. alcoholic beverage - barley -

Statistical Syllogism

going from a generalization to a conclusion. ex: 90% of old people are retired, see an old person, assume they are retired N must be at least 50% N is 100% -> valid deductive argument. The premises are true, the conclusion is true. new information and induction: may weaken the inductive argument. Inference to be strong: candidate must be randomly selected. N must be a large number

unless

if not

Alternative explanations

important rule to assessing abductive arguments. More than just accepting that the explanations were given, we can also consider there are other arguments that are plausible

The importance of definitions

it is important to arrive at a good definition that both parties find acceptable We should know what our opponent and I find the same key term If an argument is worth pursuing, we need to define they key terms (similar to 1) "God doesn't exist" "Who say there's evil in the word?" (Get them on the same page, clarify them the same definition of the word)

In order for a sentence to express a statement (?)

it must pass the true/false test. To be a statement: It is true that all men are mortal (does the bold sentence pass the true/false test) It is true that... (litmus test) (grammar) if it's a rhetorical question, it could be considered a statement. No: 1. Is it possible to agree with what this racists say? 2. Realise your potential with this new shampoo. 3. Please support the impecunious. 4. Don't argue with the teacher. 5. Show your family you really love them this holiday. 6. You will do what I tell you to do and no 'buts' (?) 7. How can anyone defend the death penalty? 8. Nobody talks to me like that! (Comment: A yes answer is also possible if we take the speaker's words literally. However, when someone protests, "Nobody talks to me like that!", what they usually mean is, "Don't talk to me like that!", which is a command and not a statement.. 9. Show your support to the unions. (?) 10. Dump your shares while you still can. 11. What on earth is going on? 12. Get a home loan today! 13. Do your bit for charity and help our save-the-bankers programme this summer by donating as much as you can. 14. What makes you think you can afford this property anyway? (?) 15. Drink three glasses of milk everyday for your health. (?) 16. Buy now to profit later.

inference indicator

it's an umbrella term which covers both conclusion-indicators and reason-indicators. (Hence, so, therefore, because, since, for..)

Inductive Generalization

knowledge is gained from samples to form conclusions about the whole (infer from samples) inductive argument strong if only the sample is large enough and unbiased.

if and only if

necessary (only if) and sufficient condition (if) You can vote if you're above 21. You can vote only if you are above 21. Being above 21 is both necessary and sufficient for being able to vote. So you can vote if and only if p if q = if q then p = q is sufficient for p p only if q = if p then q = if not q then not p = q is necessary for p If the temperature is not above 40, it won't explode. The temperature is 56. Therefore, it will explode. We mistaken a necessary for a sufficient condition.

Simplification and addition (valid)

p and q therefore p (simplification) (valid) p therefore either p or q (addition) (valid)

Inductive inference

premises are supposed only to make the conclusion highly probable. The arguer is only trying to give a strong inference. only require a strong inference Premise doesn't guarantee the conclusion (Strong/moderate induction) (Degree) An inference is (relatively) strong if and only if: "True premises make it highly likely that the conclusion is true" ; or "If the premises were to be true, the conclusion would be highly likely to be true." A good inductive argument must have true premises and a strong inference.

deductive inference

premises are supposed to logically guarantee the conclusion. The arguer is trying to give a valid inference. (degree) No possibility that it would be inductive. note: you dont need to change the language to make it "deductive" by using "probability language" note: if you think it's inductive or vice versa, what are you disagreeing with? the premise or the inference. Valid is only helpful if the premises are true. An inference is valid if and only if: "True premises are sufficient for the conclusion to be true"; or "If the premises were to be true, the conclusion would have to be true." A good deductive argument must have true premises and a valid inference.

forms of deductive arguments

propositional forms (videos) categorical forms Deduction: cannot attack inference Propositional: (we looking at the inference when it's the form. Not the premise) The premise may not be true is what important. (it does follow that p is then q) Modus ponens (Valid) if p then q p therefore: q p= he lives in Bangkok q= he lives in Thailand p is antecedent q is consequent p subset of q q if p Fallacy of denying the antecedent (invalid) If p then q Not p therefore: not q (invalid) Modus Tollens (valid) If p then q, Not q therefore: not p eg. whistle/ foul Facllacy of affirming the consequent. if p then q q therefore: P trick: how does if then statement goes? (conditional statement) what does the second premise do? the principle of charity or charitable interpretation requires interpreting a speaker's statements in the most rational way possible and, in the case of any argument, considering its best, strongest possible interpretation summary: valid: p then q not q then not p invalid: q then p (affirming the consequent) not p then no q (denying the antecedent)

Argument =

reasons + inference + conclusion argument is a bunch of statement, which the conclusion is held to be true based on the strength of the truth of the others. Inference is the movement from reasons to conclusion Since (reason indicator) it's raining, the streets are wet. (conclusion) If it's raining, the streets are wet ("if" is not a reason indicator, never break up a conditional statement.) Question is: do i believe when i say the statement?

Ad hoc explanations

special purpose explanations are made up so that any inconsistencies can be readily explained i.e we can't verify the explanations ex: bible ark wood- god give special wood.

ostensive definition

specifies the meaning of a term by pointing to objects in its extension "What is an ant?" "it's one of those" (pointing to an ant) You can also give a point of reference or a token (an example) of the type of thing eg. Emma green dress yesterday

Appeal to Ignorance

the claim that we have no evidence supporting some statement is taken as a reason for concluding that statement is false. Hidden assumption: if such and such were true, it's likely there would be good evidence. Fallacious appeals to ignorance 1. i have not seen any proof that you are innocent 2. if you are innocent you should be able to prove it to me. (we don't agree this You are innocent until proven guilty. Therefore you are guilty. Non-fallacious appeal to ignorance 1. Extensive searching for the Loch Ness Monster over 80 years has found no evidence of it. If the monster did exist it's likely there would be evidence by now. (different from aliens as the area is small compare to the universe) Therefore, there's no Loch Ness monster. eg. ( 1. fallacious 2. non-fallacious 3. missing premise: opposite of conclusion from the first fragment statement 4. eg. subordinates don't have problem. if subordinates have a problem, you would have known 5. Fallacious Burden of proof is based on the person who make the claim. You need to defend your claim. You know the effective strategy is to shift. THERE ARE CASES WHERE BOTH PEOPLE DEMAND BURDEN OF PROOF. MISUSING IT. Conspiracy theories: they play on the people for the missing implicit premise and our problems with appeals to ignorance. Which conspiracies are real? (cost-benefits analysis) Could the benefits be better achieved by other means? Are the cost of carrying out the conspiracy likely to outweigh the benefits it may bring? 1. what we really hope to find is evidence of the conspiracy itself? Eg. put mass weapon destruction in Iraq so US could invade. instead of destroying the world trade center. - paranoid - confirmation bias - complacent and naive - guard against the temptation to think that no one is capable of orchestrating and conceal extreme wrongdoing.

Definiendum

the word being defined

Conclusion indicators

therefore, wherefore, thus, consequently, we may infer, accordingly, we may conclude, it must be that, for this reason, so, entails that, hence, it follows that, implies that, as a result With this, it becomes clear that which statement is conclusion

Critical thinking

thinking that does not blindly accept arguments and conclusions. Rather, it examines assumptions, discerns hidden values, evaluates evidence, and assesses conclusions. Justified belief vs belief belief to knowledge - is there a good reason/justification for your belief? Look by the answer, and see which one is the subset of the other. The sentence that claims less are more likely to be true. see if it's a claim vs argument. (BE CAREFUL)

Transposition vs modus tollens

transposition: (both if) if p then q therefore if not q then not p it does exactly like modus tollens. Transposition includes the hypothetical into the conclusion if p then q not q (this is asserting while the above not) therefore -> not p

sampling bias

unrepresentative of the population as a whole. We need to be randomly selecting. Environment bias self-selection bias: survivor-ship bias

valid and unsound

valid means logical sound means the premise itself makes sense