Philosophy Chapter 1

A _____________ is a word or phrase that stands for a class of things

A term

What argument form is this? If A, then B. B. So, A.

Fallacy of affirming the consequent (this is an invalid argument form).

What form is this? If A, then B Not A So, Not B

Fallacy of denying the antecedent (note this is an invalid argument form).

Is the following argument valid? Some Americans work in business. Donald Trump is an American. So, Donald Trump works in business.

No, this argument is invalid because the premises do not guarantee the conclusion. This is an example of how an argument can be invalid even with true premises and a true conclusion.

Is the following argument valid? All dogs are animals. All cats are animals. Hence, all dogs are cats.

No, this argument is invalid, the premises do not guarantee the conclusion. There are two true premises but a false conclusion.

__________ ___________ are alternate ways of saying the same way Ex: Given that it is raining, the ground is wet Assuming that it is raining, the ground is wet The ground is wet if it is raining

Stylistic variants

T/F, for disjunctives "Either A or B" is inclusive, meaning it's either A or B or both.

True.

Categorial statements are often signaled by terms like "__________," "__________," and "__________" because they make claims about what all, some, or none of the members of a class are like.

"all," "some," and "no"

What are the five steps to the counterexample method? 1. 2. 3. 4. 5.

1. Identify the most logically sensitive form of the argument. Use capital letters to stand for statements or terms. 2. Find English statements or terms that, if substituted for the capital letters in the conclusion of the argument form, produce a well-known falsehood. 3. Substitute these English statements or terms for the relevant capital letters uniformly throughout the argument form. 4. Find English statements or terms that, if substituted uniformly for the remaining capital letters in the argument form, produce premises that are well known truths. 5. Check your work. If you have succeeded, you have shown the argument to be invalid.

What are the three categories that unsound arguments fall in? 1. 2. 3.

1. It is valid, but it has at least one false premise 2. It is invalid, but has all true premises 3. It is invalid, but has at least one false premise

List the five famous valid forms 1. 2. 3. 4. 5.

1. Modus ponens 2. Modus tollens 3. Hypothetical syllogism 4. Disjunctive syllogism 5. Constructive dilemma

Is this a deductive or inductive argument? 1. Most philosophers like logic. Ned is a philosopher, so Ned likes logic. 2. All philosophers like logic. Ned is a philosopher, so Ned likes logic.

1. is an inductive argument because it is probable (not guaranteed) that if the premise is true then the conclusion is true as well. 2. is a deductive argument because the premises guarantee the conclusion, it is guaranteed that if the premises are true then the conclusion is true.

_________ ___________ valid form combines both conditional and disjunctive statements.

Constructive dilemma

What type of formally valid argument is this Either A or B Not A So B ------------------------------ Either A or B Not B So A

Disjunctive syllogism

Name the famous valid form: ____: Either A or B. Not A. So, B (or Either A or B. Not B. So, A) ____: If A, then B. If B, then C. So, if A, then C ____: If A, then B. Not B. So, not A. ____: If A, then B. A. So, B. ____: Either A or B. If A, then C. If B, then D. So, either C or D.

Disjunctive syllogism Hypothetical syllogism Modus tollens Modus ponens Constructive dilemma

T/F, if is always an introduction to an antecedent.

False

T/F, statements can be valid, invalid, sound, or unsound. T/F, a given premise is either true or false, but it cannot be valid, invalid, sound, or unsound.

False, arguments can be valid, invalid, sound, or unsound, not statements. True

T/F, it is possible in a valid argument for the premises to be true while the conclusion is false.

False, in a valid argument, it is absolutely impossible for the premises to be true while the conclusion is false.

T/F, in theory, the counterexample method can conclusively establish the invalidity of an argument.

False, in theory, the counterexample method CANNOT conclusively establish the invalidity of an argument.

T/F, validity preserves falsehood. Meaning if we start with a false premise and reason validly, we are bound to wind up with a false conclusion.

False, validity does NOT preserve falsehood. False premises plus valid reasoning may lead to either truth or falsity.

T/F, we can conclude that an argument is valid if its premises are all true.

False, we CANNOT rightly conclude that an argument is valid simply on the grounds that its premises are all true.

Name this formally valid form If A, then B. If B, then C. So, If A, then C.

Hypothetical syllogism

An __________ argument is a deductive argument in which the premises fail to guarantee the conclusion.

Invalid argument

An __________ argument is one in which it is not necessary that, if the premises are true, then the conclusion is true.

Invalid.

What argument form is this? If A, then B A So, B.

Modus Ponens

What argument form is this? If A, then B. Not B. So, Not A.

Modus Tollens

____________ ____________ argument affirms the antecedent of its conditional premise and its conclusion affirms the consequent.

Modus ponens

Are these statements? 1. get your dog off my lawn! 2. how many dogs do you own? 3. let's get a dog.

No, 1. is a command that can be obeyed or disobeyed, but it makes no sense to say a command is true or false. 2. is a question which can be answered or unanswered but cannot be true or false. 3. is a proposal which can be accepted or rejected but cannot be true or false.

Is the following argument valid? Some Americans are women. Ashton Kutcher is an American. Therefore, Ashton Kutcher is a woman.

No, that argument is invalid, because the premises do not guarantee the conclusion. This example shows that just because an argument has all true premises does not mean it is valid.

Is the following argument valid? Some Americans work in the television industry. Ellen DeGeneres is an American. Hence, Ellen DeGeneres works in the television industry.

No, the following argument is not valid even though the premises and the conclusion are all true. This shows that even though an argument has a true premises and a true conclusion, it is does not always mean it is valid.

Is the following form a disjunctive syllogism? 1. Either A or B; not both A and B 2. A 3. So, Not B

No, this argument is formally valid though.

Is the following argument valid? Every genius is a philosopher. Forrest Gump is a philosopher. So, Forrest Gump is a genius.

No, this argument is invalid because Forrest Gump can be a philosopher but not be the genius type of philosopher. This is an example of an invalid argument with false premise and a false conclusion.

Is this argument valid? All reliabilists are foundationalists. William is a foundationalist. Thus, William is a reliabilist.

No, this argument is invalid because William could be a foundationalist who is not a reliabilsts. Think of it like this: All X's are Y's. William is a Y. Thus, William is an X. Just because William is a Y does not guarantee that he is an X.

Is this argument valid? Everything colored is red. Stephen Colbert is a mortician. So, Stephen Colbert is hilarious.

No, this argument is invalid because the premises do not guarantee the conclusion. This is an example of an invalid argument with false premises and a true conclusion.

Is this argument sound? All birds are animals. Some grizzly bears are not animals. Therefore, some grizzly bears are not birds.

No, this argument is not sound even though it is valid. It is not sound because it has a false premise.

A ___________ argument is a deductive argument that is valid and has all true premises.

Sound argument

A ___________ argument is a valid argument in which all the premises are true.

Sound argument

What are the three steps in the famous forms method? Step 1 Step 2 Step 3

Step 1: Identify the component statements in the argument, uniformly labeling each with a capital letter Step 2: Rewrite the argument using capital letters instead of English statements and eliminate any stylistic variants. Step 3: Check to see whether the pattern of reasoning is taken from our list of famous forms. If it is, then the argument is valid

T/F, all invalid arguments are unsound.

True

T/F, an argument can be valid even if it is a substitution instance of an invalid argument form.

True

T/F, another limitation of the famous forms method is that it does nothing to help us show that any invalid argument is invalid. It is concerned only with showing the validity of arguments.

True

T/F, conditionals are hypothetical meaning one does not assert that its antecedent is true. Nor does one assert that its consequent is true. Rather, one asserts that if the antecedent is true, then the consequent is true.

True

T/F, deductive logic is the study of methods for evaluating whether the premises of an argument guarantee its conclusion; that is, deductive logic is the study of methods of evaluating whether or not an argument is valid.

True

T/F, every substitution instance of modus ponens will be valid.

True

T/F, in a valid argument there is a necessary connection between the premises and the conclusion. the conclusion doesn't just happen to be true given the premises, rather, the truth of the conclusion is guaranteed given the truth of the premises.

True

T/F, in an invalid argument it is possible for the premises to be true while the conclusion is false.

True

T/F, modus tollens is a formally valid argument form.

True

T/F, the counterexample method counts many valid arguments that contain categorial statements as invalid.

True

T/F, the limitation of the famous forms method is that it covers the validity of arguments within only the five most famous forms, there are other formally valid forms that it does not cover.

True

T/F, the order of the premises in a formally valid argument form does NOT matter.

True Ex: 1. If Shakespeare was a physicist, then he was a scientist. Shakespeare was not a scientist. So, Shakespeare was not a physicist. 2. Shakespeare was not a scientist. If Shakespeare was a physicist, then he was a scientist. So Shakespeare was not a physicist.

T/F, valid arguments have a conditional if-then aspect, saying if the premises are true then the conclusion is true. T/F, if an argument is valid, then it is not necessary that, if its premises are true, then its conclusion is true also.

True False, if an argument is valid, the it IS necessary that, if its premises are true, then its conclusion is true also

T/F, in some arguments, the conclusion is adequately supported by the premises, in other arguments it is not. T/F, A set of statements counts as an argument as long as some of the statements are intended to support another.

True True

T/F, valid arguments with all premises true are sound. T/F, valid arguments with at least one false premise are unsound.

True True

T/F, truth and falsehood are the two possible truth values. T/F, a statement is a declarative sentence that has truth value. T/F, commands, questions, and proposals cannot be true are false, and therefore are not statements.

True True True

T/F, validity is not enough all by itself for a good deductive argument T/F, truth is not enough all by itself for a good deductive argument.

True (a valid argument with false premises can lead to a false conclusion). True

T/F, since there are two types of arguments there are also two types of logics.

True (deductive logic and inductive logic).

T/F, logicians focus on the link between the premises and the conclusion to determine validity instead of the actual truth or falsity of the statements in the argument.

True, an argument can be false but still be valid.

T/F, we want our deductive arguments to be sound, but that is not all we want. We want more from a deductive argument than for it to just be sound.

True, an argument can be sound but "Beg the question" for example.

T/F, If an argument is valid and has a false conclusion then it must have at least one false premise.

True, if it had true premises then it would have to have a true conclusion because it is VALID.

T/F all arguments of disjunctive syllogism are valid.

True, it is a formally valid argument form.

T/F, if an argument has the modus ponens form then it is valid because of the form alone.

True, its validity does not depend on its subject matter.

T/F, validity preserves truth.

True, this means that if we start with the truth and reason in a valid fashion, then we will wind up with truth.

T/F, arguments are neither true nor false, but each statement is either true or false.

True.

T/F, every argument with the hypothetical syllogism form is valid.

True.

T/F, the question "Are the premises and the conclusion actually true?" is distinct from the question "Is the argument valid?"

True.

An _______ argument is one that is either invalid or has at least one false premise.

Unsound argument

A _____ argument is one in which it is necessary that, if the premises are true, then the conclusion is true.

Valid argument

A __________ argument is a deductive argument in which the premises succeed in guaranteeing the conclusion.

Valid argument (Just because a deductive argument intends to guarantee the conclusion doesn't mean it always is successful in doing so... so when it is successful it is a valid argument)

Is this a sound argument? If Mozart was a composer, then he understood music. Mozart was a composer. Hence, Mozart understood music.

Yes, this argument is sound because it is valid and has true premises.

Is this argument valid? All philosophers are nerds. So, no squares are circles.

Yes, this argument is valid but not formally valid. It is valid because of the content of the conclusion not because of the structure of the argument. (It is impossible for the premise to be true when the conclusion is false).

Is the following argument valid? All sharks are birds. All birds are predators. So, all sharks are predators.

Yes, this argument is valid even if both premises are false.

Is the following argument valid? All birds are animals. Some cats are birds. So, some cats are animals.

Yes, this argument is valid even if it is false.

Is this argument valid? Either Bill has a poor memory or he is lying. Bill does not have a poor memory. Therefore, Bill is lying

Yes, valid argument because premises absolutely guarantee the conclusion

The if part of a conditional statement is the _________ and the then part is the _____________

antecedent; consequent

An _________ is a set of statements where some of the statements, called the premises, are intended to support another, called the conclusion

argument

An _________ _________ is a pattern of reasoning.

argument form

An ___________ is a set of statements where some of the statements are intended to support another. The _________ is the claim to be supported. The _________ are the statements offered in support.

argument; conclusion; premises

In logic, the word some means ________ ________ _________.

at least one

A ____________ ________________ is a statement that relates two classes or categories, where a class is a set or collection of things.

categorial statement

an if-then statement is a ________ statement.

conditional statement.

A modus tollens argument denies the _________ of its conditional premise, and the conclusion denies the _________.

consequent; antecedent

What type of valid argument form is this? Either A or B. If A, then C. If B, then D. So, Either C or D.

constructive dilemma

A ________________ to an argument form is a substitution instance in which the premises are true and the conclusion is false.

counterexample

A __________________ to the form of an argument shows that the form is not valid by showing that the form does not preserve truth -- that is, it shows that it can lead from true premises to false conclusion.

counterexample

A(n) __________ argument is one in which the premises are intended to guarantee the conclusion. A(n) __________ argument is one in which the premises are intended to make the conclusion probable, without guaranteeing it.

deductive argument inductive argument

___________ logic is the study of methods for evaluating whether the premises of an argument guarantee its conclusion. ____________ logic is the study of methods for evaluating whether the premises of an argument make its conclusion probable, without guaranteeing it.

deductive logic inductive logic

A ___________ is an either-or statement - for example, "Either A or B": the parts are __________

disjunction; disjuncts

A __________ is an error in reasoning.

fallacy

The ______ ______ method uses the validly famous forms of an argument and three steps in order to determine if an argument is valid or not.

famous forms method.

________ ________ argument is one that is valid in virtue of its form.

formally valid argument (modus ponens is an example of this).

A ____________ _____________ to an argument form is a substitution instance in which the premises are well-known truths and the conclusion is a well known falsehood.

good counterexample.

An __________ __________ __________ is one that has some invalid substitution instances.

invalid argument form.

Roughly speaking, __________ is the study of methods for evaluating arguments.

logic

_________ is the study of methods for evaluating whether the premises of an argument adequately support its conclusion

logic

Modus tollens is related to modus ponens in that they both have a premise that is a conditional statement. The key difference is that modus tollens has a ____________.

negation

The __________ of a statement is its denial for example, "It is not the case that A."

negation

A ___________ is a declarative sentence that is either true or false.

statement

A _________ _____________ is one in which it is probable (but not necessary) that, if the premises are true, then the conclusion is true.

strong argument

A __________ ____________ of an argument form is an argument that results from uniformly replacing the variables in that form with statements (or terms).

substitution instance

A ________ _______ form is one in which every substitution instance is a valid argument.

valid argument form.