Logic mid term
T or F? A single conditional statement (if X, then Y) is an argument
False
T or F? A statement is an attempt to prove that a conclusion is either probably or necessarily true by presenting evidence in support of that conclusion
False
T or F? An argument may only contain one statment
False
T or F? Bivalence is a principle of logic stating that arguments must be either deductive or inductive.
False
T or F? If an argument contains at least one false premise, it cannot be valid
False
T or F? If the conclusion of a deductive argument is actually true, then the argument cannot be invalid.
False
T or F? If there are at least two statements in a passage, the passage must contain an argument.
False
T or F? A question may serve as either a premise or conclusion in an argument
False, Questions do not have a truth value or a fact.
T or F? In order to test the strength of an inductive argument, one must ask the following question: "If the premises are assumed to be true, is it possible for the conclusion to be false.
False, change to "is it likely for the conclusion to be true"
T or F? A strong argument must contain premises that are all true
False, could also be false
T or F? If an argument is valid, then the premises are actually true
False, could also be false. Premises can be either true or false.
T or F? An argument may contain only one simple statement.
False, it must contain two
T or F? Validity is always determined by asking the following question: "If the premises are assumed to be true, is it possible for the conclusion to be true"
False, it would be possible for the conclusion to be false
T or F? Some deductive arguments are neither valid nor invalid
False, not in-between, they are either valid or invalid.
T or F? A deductive argument is valid, by definition
False, valid or invalid
T or F? An invalid argument must contain at least one statement that is actually false
False, validity has nothing to do with true/false
N, V, I, S, W? If X is the case, then Y is the case. if Z is the case, then Y is the case. Hence, if Z is the case, then X is the case.
Invalid If X, then Y If z, then Y Hence, if z then x If the consequent like above is above is the same it is invalid. Correct formate: If x, then Y If y, then z Hence, if x, then z
N, V, I, S, W? Anyone who lives in Sydney lives in Australia. Maria does not live in Sydney, so Maria does not live in Australia.
Invalid If S, then A Not-S Hence, not-A
N, V, I, S, W? If many persons are sentenced to death due to mistakes by police or prosecutors, then the death penalty should be abloished. No persons are stenenced to death due to mistakes by police or prosecutors. Therefore, the death penalty should not be abolished.
Invalid If S, then D Not-S Hence, not-D
N, V, I, S, W? Anyone who lives in Sydney also lives in Australia. Deena lives in Australia, so Deena lives in Sydney.
Invalid The conclusion doesn't matter because nothing follows If S, then A A Hence, S
N, V, I, S, W? No A are B. Some B are not C. Som some A are too c.
Invalid (both negative premises)
N, V, I, S, W? Bridgeport is ten miles from Oxford and Oxford is ten miles from Jasper. So, Bridgeport is necessarily twenty miles from Jasper.
Invalid (you don't know the specific location, tries to force a premises that could be true)
N, V, I, S, W? If gophers are golden, then my pet gopher Max is Golden. Max is golden, therefore, gophers are golden.
Invalid, If G, then M M--> affirms the consequent Hence, G
N, V, I, S, W? Cicero was a Roman orator or Cicero was a Roman politician. Cicero was a Roman orator. Therefore, Cicero was not a Roman politician
Invalid, O or p O Thence, not-p (or statement is at least one is true but not both might be), If the second line of it affirms it it would be invalid. The second line has to deny one of the options 'not-blank-
N, V, I, S, W? Some C are not A. No B are A. Hence, some C are B.
Invalid, both premises are negative. you need a positive "all & some" or "some & all", "some & no" are two negatives. Having two negatives automatically makes it invalid.
N, V, I, S, W? All crows are black. My pet bird is black. therefore, my pet bird is a crow.
Invalid, the shot at being perfect
N, V, I, S, W? Sammy said that Katie was dishonest
N
N, V, I, S, W? Is it any wonder why society is so messed up
Not an argument
N, V, I, S, W? We went to a movie today. It wasn't good.
Not an argument
N, V, I, S, W? Retired marathon runner Dylan is 60 years old and is currently in coma. So, there is no way that Dylan will compete in the marathon scheduled six months from now.
Strong
N, V, I, S, W? Sam is a line cook. Most line cooks are good cooks. So, Sam can probably cook well.
Strong
N, V, I, S, W? The eminent of historian of British history, A.O. Scott, stated that the British empire once included a colony in Australia. So, Australia was once part of the British empire.
Strong (appeal to an authority)
N, V, I, S, W? If you won the lottery, you can buy that new car you've been wanting, There's a 70% chance that you won the lottery. So, you can probably buy that new car you've been wanting.
Strong (the percentage makes it inductive) If L, then C
N, V, I, S, W? Jack works as an electrician for electrical solutions. Most of the electricians who work for Electrical Solutions studied as an apprentice, So, Jack studied as an apprentice.
Strong, (most signifies induction bc it means majority)
N, V, I, S, W? According to my logic textbook, a vlid argument is deductive. So, valid arguments must be deductive.
Strong, Appeal to an authority
N, V, I, S, W? The nutrition label on this box of cereal says that there is not sugar, in a single serving of the cereal. Therefore, there is no sugar in a single serving of this cereal.
Strong, Similar to a road sign, has to do with probability or likelihood.
N, V, I, S, W? Most Wombats eat carrots. Cecil is a wombat, so cecil eats carrots.
Strong, most indicates over 50%
N, V, I, S, W? Smoking cigarettes may harm one's health. So, it's best to avoid smoking assuming one wants to be healthy,
Strong, the word may makes it a matter of probability
T or F? A deductive argument aims to prove that a conclusion is probably true rather than necessarily true.
True
T or F? A premise is a statement that serves as evidence in an argument
True
T or F? A statement is either true or false, but not both
True
T or F? A strong argument may have a conclusion that is actually false
True
T or F? A valid argument is deductive, by definition
True
T or F? An inductive argument may present powerful evidence for a conclusion that is actually false.
True
T or F? An invalid argument may be composed of statements that are all actually true
True
T or F? No matter how strong an inductive argument is, the conclusion could be false
True
T or F? Statements must be either true or false, but not both
True
T or F? The actual truth value of the premises is not relevant for determining validity
True
T or F? A valid argument may be composed of premises that are actually false.
True, Validity does not require a truth
T or F? Some inductive arguments are neither very strong nor very weak
True, could be 50/50
N, V, I, S, W? Everyone who studies logic will become a better student. Ralph is studying logic. So, Ralph will become a better student.
Valid
N, V, I, S, W? All dogs are hairy. All hairy animals go to heaven. Therefore, all dogs go to heaven
Valid All D are H All H are B Hence all D are B
N, V, I, S, W? All the whales have wings. Moby does not have wings. So Moby is not a whale.
Valid If H, then W not-w Hence, not-h (modus tollens)
N, V, I, S, W? If Detroit is on the east coast, then Detroit is in Michigan. Detroit is on the east coast. So Detroit us in Michigan.
Valid If D, the E D Hence, M
N, V, I, S, W? All pigs can fly. Anything that can fly can swim. So al pigs can swim.
Valid If P, then F If F, then S If P, then S
N, V, I, S, W? All internet spies for the government are NSA employees. Lee is not an NSA employee. So, Lee is not an internet spy for the government.
Valid If S, then N Not-N Hence not-S
N, V, I, S, W? If someone is sick they are unhappy. Katie is happy, so Katie is not sick.
Valid If s, then not-h H Hence, not -s (modus tollens)
N, V, I, S, W? No A are B. Some A are C. So, Some C are not B.
Valid Stron
N, V, I, S, W? Bloom does not wish to be an accountant, for if he wished to be an accountant, he would be enrolled in the business college, and he is not enrolled in the business college.
Valid, If A, then B Not-B Hence, Not A
N, V, I, S, W? If Kant had a dog, then it was named Barky. If it was named Barky, then it had a collar with its name engraved on it. Therefore, if Kant had a dog, then it had a collar with its name engraved on it.
Valid, these are all conditional statements
N, V, I, S, W? If Kay names her dog Fido, then the moon is not made of cheese. But the moon is made of cheese. Therefore, Kay will not name her dog Fido.
Valid. If f, then not-C C Hence, not-f
N, V, I, S, W? In a recent speech, the president of the automotive company General Motors asserted that our country has drifted dangerously away from its religious and ethical moorings. In light of this pronouncement, we should be concerned about the future of this country.
Weak
N, V, I, S, W? There are five holes in the humans head, a mouth, two nostrils, and two ears. Therefore, the number of planets in the solar system is likely five.
Weak
N, V, I, S, W? Several commenters on internet discussion sites claim that no human being has ever walked on the Moon. Therefore, it's unlikely that humans have every walked on the Moon.
Weak (appeal to an authority) the authority is unknown
N, V, I, S, W? Katie bought 100 Bonanza Lottery tickets yesterday. There are 50,000 Bonanza lottery tickets already sold and only lottery ticket will be a winner. So, Katie will likely win that lottery with one of her 100 tickets.
Weak (low probability)
N, V, I, S, W? Alissa has a class with three freshmen who disrupt the class and all three are failing. Based on Alissa's report, we should conclude that freshmen are not serious students.
Weak, (insufficient sample size)
N, V, I, S, W? My barber said that Napoleon was an effective military general. So, Napoleon must have been a great military leader.
Weak, appeals to an authority.
T or F? A question may serve as a premise or conclusion in an argument
false.
N, V, I, S, W? Only crows are black. My pet is black. So, my pet is crow.
invalid
T or F? A premise is a statement that serves as evidence in an argument
true
