Philosophy 201 Clark Wolf Iowa State University Spring 2013.

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Philosophy 201 Clark Wolf Iowa State University Spring 2013

Transcript of Philosophy 201 Clark Wolf Iowa State University Spring 2013.

Philosophy 201

Clark Wolf

Iowa State University

Spring 2013

Philosophy 201: Syllabus

Be sure you can access on-line version of the syllabus! (It will be available this evening at the URL listed.)

Required Text:

Other sources

available on line.

Philosophy 201Assessment: (Quantitative)

Daily Argument Analysis Exercise, or occasional quiz at the beginning of class.

Brief Writing Assignment (10%) Midterm/Final Exams (40% / 45%) Optional Extended Writing Assignment

Other Considerations: Attendance, Preparation, Any occasional homework notices.

Philosophy 201:Argument Analysis Exercises: We will

typically start class– the first five minutes– with a short exercise. I will put a prose argument on screen, and your job will be to analyze it, identifying the claim to be supported and the evidence given for that claim. I will collect these at 10:05, and we will briefly discuss the answers. If you do not turn in a 3X5 index card at this time, you will be marked ‘absent’ from class for that day.

Philosophy 201

Objectives: Why study philosophy? How should Intro Philosophy be organized?

History? Topics?

What should you expect to gain from this class?

Philosophy 201:

Skills Ability to recognize, analyze, and evaluate

arguments. Ability to read and understand complex texts. Ability to think clearly and articulate

alternative perspectives on several important philosophical questions

Philosophy 201History of Ideas and Figures:

Plato Aristotle Epicurus Epictetus Sextus Empiricus Rene Descartes Arthur Schopenhauer John Stuart Mill William James …

Philosophy 201:

Topics: What can we know? What goals are worth pursuing in life? What kinds of things exist? Is there evidence for the existence of God? What is justice? When can the state

appropriately limit people’s liberty? Does life– my life– have meaning?

First Reading Assignment:

“Notes on Logic and Critical Thinking”

Available on line-- to be linked from the on-line version of the syllabus.

Reasoning and Argument Analysis

Clark WolfDirector of Bioethics Iowa State University

[email protected]

Argument for Analysis:

Don’t worry too much about these arguments– do the best you can. The purpose is to get practice, not to punish conscientious attempts.

The arguments will get harder (sometimes) as the semester moves forward.

Argument for Analysis:Please provide an interpretation of this argument in STANDARD FORM on a 3X5

index card, with your name on it, and turn it in at 10:05.

“Thoughtless people think that gun control laws will make us safer, but such laws are a stupid way to ‘protect the public.’ Criminals don’t obey the law, so they will have guns whether or not these laws are in place. But law abiding citizens who do obey the law would be disarmed by these laws: If we have guns, we can protect ourselves, but if we’re denied them we’re at the mercy of those who have them! If criminals have guns, it’s better– the public is safer-- if other people also have guns! Then they have at least a fighting chance. In the end, these silly laws make us less safe, not more safe. They make it safer for the criminals, who can be assured that we’re unarmed, but less safe for the rest of us who can no longer defend ourselves.”

OBJECTIVES: On completion of this unit, students should be able…

1.1 …to recognize when they are presented with an argument,1.2 …to analyze arguments by identifying the conclusion and

distinguishing conclusions from premises.1.3 …to evaluate arguments by considering the plausibility of the

premises and the extent to which the premises support the conclusion.

1.4 …to distinguish deductive and inductive arguments,1.5 …to distinguish an argument’s content from its form.1.5 …to define key concepts: argument, premise, conclusion,

evidence, rationally persuasive argument, fallacy, valid argument, invalid argument, inductive argument, abductive argument.

1.6 …to evaluate arguments, by (i) distinguishing premises from conclusion, (ii) putting the argument in standard form, (iii) critically examining the premises, and (iv) evaluating the inference from premises to conclusion.

1.7 …to be self-reflectively critical of their own arguments and those of others.

What is an Argument?

Argument: A set of statements, some of which serve as premises, one of which serves as a conclusion, such that the premises purport to give evidence for the conclusion.

Premise: A premise is a statement that purports to give evidence for the conclusion.

Evidence: To say that a statement A is evidence for another statement B is to say that if A were true, this would provide some reason to believe that B is true.

Conclusion: The statement in an argument that is supposedly supported by the evidence.

When do we encounter arguments?

Any time anyone tries to persuade you of something, or to make you change your mind.

Rational persuasion uses reasons, but even irrational persuasion employs reasons (bad reasons). In evaluating arguments, we need to be able to evaluate reasons and patterns of reasoning.

Arguments can be used to persuade, inform, and investigate.

They can also be used to bamboozle, confuse, and frustrate.

Example: from “Thank you for Smoking!” http://www.youtube.com/watch?v=DrnZdFFovBE

Nick: OK, let’s say you’re defending chocolate and I’m defending vanilla. Now if I were to say to you “vanilla is the best flavor ice cream,” you’d say…?

Joey: No, Chocolate is. Nick: Exactly. But you can’t win that argument. So, I’ll ask

you, “So you think chocolate is the end all and be all of ice cream, do you?

Joey: It’s the best ice cream. I wouldn’t order any other.Nick: Oh, so it’s all chocolate for you, is it? Joey: Yes, chocolate is all I need.Nick: Well, I need more than chocolate. And for that matter, I

need more than vanilla. I believe that we need freedom, and choice when it comes to our ice cream, and that, Joey Naylor, that is the definition of liberty.

Joey: But that’s not what we’re talking about. Nick: Ah, but that’s what I’m talking about.

-from “Thank you for Smoking” (Film)

Joey: But that’s not what we’re talking about. Nick: Ah, but that’s what I’m talking about. Joey: But you didn’t prove that vanilla is the best. Nick: I didn’t have to. I proved that you are wrong,

and if you’re wrong, I’m right. Joey: But you didn’t convince me.Nick: I’m not after you, I’m after them. (pointing to

the crowd around them)

-from “Thank you for Smoking” (Film)

Rational Argument v. Persuasive Rhetoric

Sometimes people are persuasive not because they are offering well-reasoned arguments, but because they are good at bamboozling other people.

Good philosophical arguments should be rationally persuasive.

Indicator Words: Indicator words: Sometimes writers use language that

indicates the structure of the argument they are giving. The following words and phrases indicate that what follows is probably the conclusion of an argument:

Conclusion Indicators:

Therefore… thus… for that reason… hence… it follows that…

Premise Indicators:

Because…Since…For…For the reason that…

Examples:

Since private business is the most effective instrument of economic change, the government should utilize the resources of private business in its economic planning and decision making.

Women work just as hard as men and are just as productive. Therefore they should be compensated the same.

Example:

“Because animals are conscious, capable of experiencing pain and pleasure, they are like people in significant respects. Since they are also intelligent—often far more intelligent than newborn babies for example, it follows that they deserve kind treatment from human beings and that it is wrong to treat them with cruelty.”

Standard Form

Standard Form: Usually we find arguments expressed in ordinary prose. But as noted, when we are evaluating arguments it is a good idea to separate the premises from the conclusion, and to put the argument into “standard form.” We say that an argument is in standard form when the premises are numbered and listed separately, and when the conclusion is clearly written underneath them.

Example:

“Because animals are conscious, capable of experiencing pain and pleasure, they are like people in significant respects. Since they are also intelligent—often far more intelligent than newborn babies for example, it follows that they deserve kind treatment from human beings and that it is wrong to treat them with cruelty.”

Standard Form Version:

(1) Animals are conscious.(2) Animals are capable of experiencing pain and pleasure.(3) Animals are intelligent.(4) Animals are like people in significant respects.

Conclusion: (5) Therefore (i) animals deserve kind treatment from humans and (ii) it is wrong to treat animals with cruelty.

A Reservation:

Whenever we put an argument in standard form, we have given an interpretation of that argument. Ideally, an interpretation should accurately capture the meaning of the original, but it is always possible to challenge the accuracy of an interpretation.

Evaluating an Argument:

“By splicing genes into crop plants, scientists have changed these crops in ways that never could have come about through the natural process of selective breeding. These changes in our food crops threaten the health of everyone in the world, and impose a great danger of massive environmental damage. Genetically modified crops are unnatural and dangerous. We should avoid using them and growing them, and should do whatever it takes to eliminate them from Iowa farms.”

Questions:

What is the author of this passage trying to persuade you to believe? (What’s the conclusion?)

What reasons are being offered? (What are the premises?)

In this argument there are few indicator words used, but it is not hard to figure out what the author would like us to believe.

What’s the Conclusion?

Conclusion: Often the conclusion of an argument is stated either in the first sentence of a paragraph, or in the last sentence of the paragraph. In this case, the conclusion—the claim the author intends to persuade us to accept—is a complex claim. The author urges that:

(1) We should avoid using and growing genetically modified crops, and

(2) We should do “whatever it takes” to eliminate these crops from Iowa farms.

What’s evidence or reasons are given?

Premises:

P1) Gene splicing changes crops in ways that could never have come about through selective breeding.

P2) Changes in food crops due to gene splicing threaten everyone’s health.

P3) Changes in food crops pose a threat of massive environmental damage.

P4) Genetic modification of crops is unnatural.P5) Genetic modification of crops is dangerous.

Step One: Are the premises true?

Premise 1: Gene splicing changes crops in ways that never could have come about through selective breeding.

Evaluation: Is this true? Some of the properties that have been induced through genetic engineering might have been produced through selective breeding. But it is unlikely that the genetic alterations that have been effected in the production of genetically modified crops would have been produced in any other way. Perhaps this premise should be somewhat qualified, but it contains a kernel of truth.

Step One: Are the premises true?

Premise 2: “Changes in food crops due to gene splicing threaten everyone’s health.

Evaluation: This claim requires additional support and evidence. Many people are concerned about the health effects of genetically modified food crops, but no one has shown that these crops are dangerous. The author of the paragraph provides no evidence that genetically modified crops are dangerous.

Step One: Are the premises true?

Premise 3: Changes in food crops pose a threat of massive environmental damage.

Evaluation: Once again, this claim requires support. There may indeed be reasons for concern about the environmental effects of genetically modified crops, but the author has not given us any evidence. Without more evidence, we may not be in a position to evaluate this premise.

Step One: Are the premises true?

Premise 4: Genetic modification of crops is unnatural.

Evaluation: The term ‘natural’ can be slippery, and we may need to know more about what the author has in mind. In context, it seems that the author regards things that are ‘unnatural’ as bad. But in an important sense, bridges, computers, vaccines and artworks are “unnatural.”

Step One: Are the premises true?

Premise 5: Genetic modification of crops is dangerous.

Evaluation: Once again we need evidence for such a claim before we can place our trust in it. In what sense is genetic modification dangerous, and what are the specific dangers the author has in mind? Without more evidence, we may simply find that we are not yet in a position to evaluate the argument.

Step Two:

If the premises were true, would they provide good evidence for the conclusions?

Are there implicit premises that should be included in the evaluation of the argument?

A Strategy for Evaluating Arguments: Of course, for the purposes of this course, your views about GM crops are not what matter. What does matter is the strategy used here for evaluating the argument under consideration:

First, identify the argument’s premises, and restate them clearly.

Second, evaluate each premise individually: is it true or false? What evidence, what information would you need to know in order to determine whether the premises are true?

If you discover that the premises of the argument are simply false, you may need to go no further. But if the premises seem true, there is a third important step to take in evaluating the argument:

Third, consider the relationship between the premises and the conclusion. What kind of argument is it? Is it a good argument of its kind?

Argument for Analysis:

“Different cultures have different moral values: For example, some cultures hold that it’s morally right to ethnically cleanse the nation by killing those who are not members of the dominant group. Some cultures hold that terrorism is morally praiseworthy, while others believe that it’s wrong to harm innocent people. But no one is in a position to say that their values are better than the cultural values of any other group. Because of this, it is inappropriate for us to impose our arbitrary cultural values on terrorists or ethnic cleansers whose values are different from ours.”

In Standard Form:

1) Different cultures have different moral values. [For example, some cultures hold that it’s morally right to ethnically cleanse the nation by killing those who are not members of the dominant group. Some cultures hold that terrorism is morally praiseworthy, while others believe that it’s wrong to harm innocent people.]

2) No one is in a position to say that their values are better than the cultural values of any other group. 3) Our own values are arbitrary, and we are unjustified in giving them special weight. (Implied premise?)

4) Conclusion: It is inappropriate for us to impose our arbitrary values on terrorists or ethnic cleansers whose values are different.

Thoughts on this Argument: If this argument goes wrong, where does it go wrong? Is it

intolerant to prevent people from harming one another?

Is ‘harmfulness’ an intercultural value that allows us to make judgments about the value systems of different cultural groups?

The argument concludes with a plea for tolerance: Should we be tolerant of all differences? Is it ‘intolerant’ to prohibit theft and assault, since thieves and assailants clearly don’t share the values that motivate our legal system. What are the limits of tolerance, and how can we justify these limits?

What is the relationship between ‘relativism’ and ‘toleration?’ If one is a relativist, would one be tolerant of others? What if ‘tolerance’ is not one of the values one’s own culture recommends? Are we tolerant when we permit others to harm and oppress?

Fallacies:

Fallacy: An argument that provides the illusion of support, but no real support, for its conclusion.

A few fallacies:Ad hominem- attacking the person instead of

addressing the argument. Ad bachilum- appealing to force rather than reason. Begging the Question- asserting a claim in an

argument intended to support it. Straw man (straw person)- attacking a weak or

absurd version of an argument, and then pretending to have refuted the strong version.

Many others!

Evaluating Philosophical Arguments:

Fair-Mindedness and the State of Suspended Judgment: When evaluating arguments, we should strive to be impartial and fair-minded. We should try to follow where the best reasons lead instead of pre-judging the conclusion.

Next: Deductive Arguments

Deductive Argument: An argument that has the property that if the premises are true, then the conclusion cannot be false.

Example: All vertibrates have hip bones. Snakes are vertibrates. Therefore, snakes have hipbones.

Deductively Valid Arguments:

Df: An argument is (df) deductively valid iff it has the property that if the premises are true, then the conclusion cannot be false.

Example: (From Aristotle’s Logic)

1) All men are mortal.

2) Socrates is a man.

3) Therefore, Socrates is mortal.

Comments: Deductive validity is a property of the form of an argument. The

following arguments have the same form

All fish are cold blooded.Whales are fish.Therefore whales are cold-blooded.

All goats are quadrupeds. Abedna is a goat.Abedna is a quadruped.

All philosophers are geniuses.Clark is a philosopher. Clark is a genius.

These arguments exemplify a valid form, so they are all valid. But note that some of these arguments contain false statements. How can an argument be valid if it has false premises?

Comments about Validity: Consider the definition:

Df: An argument is (df) deductively valid iff it has the property that if the premises are true, then the conclusion cannot be false.

A valid argument can have false premises. A valid argument can have a false conclusion. A valid argument can have false premises and a false

conclusion. A valid argument can have false premises and a true

conclusion.

A valid argument cannot have true premises and a false conclusion.

Examples…

Comments about Validity:Two Examples of Valid (but faulty) Arguments:

False premises and false conclusion:

1) All horses are reptiles.2) All reptiles have wings.3) Therefore all horses have wings.

False Premises, True Conclusion:

1) All horses are reptiles.2) All reptiles have fur. 3) All horses have fur.

These are both valid arguments. Since their premises are false, they do not provide good evidence for their conclusions.

Soundness:

An argument is sound iff it is deductively valid, and its premises are true.

Some Valid Argument Forms:

Modus Ponens: If X then Y.X.Therefore, Y.

Example:

1) If Jon swam in the Skunk river, then he’ll stink. 2) Jon swam in the skunk river. 3) Jon stinks.

Some Valid Argument Forms:

Modus Tollens: If X then Y.not Y.Therefore, not X.

Example:

1) If Jon swam in the Skunk river, then he’ll stink. 2) Jon doesn’t stink. 3) Jon didn’t go swimming in the Skunk.

Some Related Invalid Forms:

Affirming the Consequent: If X then Y.Y.Therefore, X.

Example:

1) If Jon swam in the Skunk river, then he’ll stink. 2) Jon stinks. 3) Jon went swimming in the Skunk.

Some Related Invalid Forms:

Affirming the Consequent: If X then Y.Y.Therefore, X.

Counter-example:

1) If Jon throws water on the streets, then the streets will be wet.

2) The streets are wet. 3) Jon must have thrown water on them.

Obviously this is a bad argument: If you find that the streets are wet, it’s more likely that it’s rained than that someone has been out dumping water around.

Some Related Invalid Forms:

Denying the Antecedent: If X then Y.Not X.Therefore, not X.

Example:

1) If Jon swam in the Skunk river, then he’ll stink. 2) Jon didn’t swim in the Skunk. 3) Jon won’t stink.

(What if he’s been out shoveling manure?)

Quiz: Which are valid? What’s the Form? 1) If he eats that fish, he’ll

die!

2) Ah! He didn’t eat the fish.

3) He must still be alive.

1) If you find a penny, you’ll have luck all day.

2) You found a penny!

3) You’ll have a lucky day.

1) If you had taken logic, you would know how to distinguish valid from invalid arguments.

2) You can’t tell which are valid and which are not!

3) You didn’t take logic.

1) If you ride your bike, you’ll get strong.

2) You’re strong!3) You must be a bike

rider.1

Quiz: Which are valid? What’s the Form? 1) If he eats that fish, he’ll die!

2) Ah! He didn’t eat the fish.

3) He must still be alive.

Invalid.

Form: Denying the Antecedent.

1) If you find a penny, you’ll have luck all day.

2) You found a penny!

3) You’ll have a lucky day.

Valid.

Form: Modus ponens.

1) If you had taken logic, you would know how to distinguish valid from invalid arguments.

2) You can’t tell which are valid and which are not!

3) You didn’t take logic.

Valid.

Modus Tollens.

1) If you ride your bike, you’ll get strong.

2) You’re strong!3) You must be a bike rider.

Invalid! Form: Affirming the Consequent.

Aristotelian Syllogisms: Some other Valid Argument Forms

All X are Y. All Y are Z. Therefore, all X are Z.

All X are Y. S is an X. S is a Y.

No X are Y. S is Y. S is not X.

All X are Y. S is not Y. S is not X.

Aristotle’s Logic is a detailed and sophisticated analysis of simple arguments like these. For almost 2000 years, this was the state of the art!

An Informal Method for Testing Validity:

1) Distinguish the argument’s form from it’s substance.2) Write out an abstract version of the argument’s form: Do

this by drawing a circle around each substantial statement and replacing it with a letter.

3) Try to fill in the letters with alternative substance in such a way that you make the premises true, and the conclusion false. This is a counterexample to the argument.

If you can find a counterexample of this kind, then you know that the argument was invalid.

Testing validity with a counterexample:

“In order to institute a stable regime in Iraq and pull out, we need help from our former allies. But if Bush wins the election, then our former allies will continue to refuse to help us. So if Bush wins the election, we will not be able to institute a stable regime and pull out of Iraq.”

“If moral relativism were true, then we should expect to find that different cultures have very different moral values. But this is just what we do find: different cultures do have different moral values. Therefore moral relativism must be true.”

Testing validity with a counterexample:

“In order to institute a stable regime in Iraq and pull out, we need help from our former allies. But if Candidate Bush wins the election, then our former allies will continue to refuse to help us. So if Bush wins the election, we will not be able to institute a stable regime and pull out of Iraq.”

Interpretation: If we wish to pull out of Iraq, then we need help from our allies.If Bush is elected we won’t have help. If Bush is elected, then we won’t be able to pull out.

Form: If X then YIf B then Not Y.If B then not X.

This argument is valid: No counterexample will be forthcoming. But note that if you fail to find a counterexample, you don’t know for sure that the argument is valid! Note also that my assurance that the argument is valid does not prove that the conclusion is true: Perhaps one of the premises is false.

Another interpretation: “If (institute a stable regime in Iraq) and (pull out) then (we need help from our former allies.) If (Bush wins) then (our allies won’t help) Therefore if (Bush wins) then (no stable regime) and (won’t pull out of Iraq).

If (X and Y) then Z. (Still valid.) If B then Not ZIf B then Not (X and Y)

One more thing to notice: Even though this argument is valid, it implies nothing about whether we will be able to pull out of Iraq and institute stability if Bush does not win. The argument is consistent, for example, with the view that we can’t accomplish these things no matter who wins the election.

Testing validity with a counterexample:

“If moral relativism were true, then we should expect to find that different cultures have very different moral values. But this is just what we do find: different cultures do have different moral values. Therefore moral relativism must be true.”

If X then Y.

Y.

Therefore X.

You already know that this argument is invalid,Since it affirms the consequent. But for a Counterexample:

Counterexample: If an animal is a dog, then it must have hair.My pet spider has hair.Therefore my pet spider is a dog.(?)

Testing Validity:

If you were to take a class in formal logic, you would learn more reliable and technical ways to test for validity. When arguments are very complicated, you can’t always simply see that they are valid or invalid.

Nondeductive Arguments Can be Good Arguments:

Deductive arguments guarantee the truth of their conclusions… given the truth of the premises.

Inductive and abductive arguments do not guarantee the truth of the conclusion, but when such arguments are strong, they provide good evidence that the conclusion is true. If you have a good non-deductive argument for a claim, then you have reason to believe that it is probably true.

Facts about Inductive Arguments:

Inductive arguments are never valid, but they may still be good arguments. Inductive arguments are said to be strong when they provide good evidence that the conclusion is true, and weak when they don’t provide good evidence.

Inductive arguments are Strong when the sample is large and representative. They are weak when the sample is small or unrepresentative.

Dick should not drink the coffee.

Inductive and Abductive Arguments

Inductive Argument (or ‘induction’):  A nondeductive argument in which characteristics of individuals not in a sample are inferred from the characteristics of individuals in a sample.

Abductive argument (or ‘abduction’): A form of nondeductive inference, also called “inference to the best explanation” in which a hypothesis is supported on the ground that it is the best explanation for some observed phenomenon.

Inductive and Abductive Arguments

Here is an example of an inductive argument:

(1) 95% of all examined fish from the Otsoga river contained dangerous levels of mercury.

(2) This fish came from the Otsoga river.

(3) Therefore, this fish (probably) contains dangerous levels of mercury.

Weak Inductive Arguments:

1) All Bob’s friends say that they plan to vote for Mitt Romney.

2) Therefore, it seems likely that Romney will carry Iowa by a landslide.

Problem: Unrepresentative Sample. ‘Bob’s friends’ are not likely to be a representative sample of Iowans as a whole. If Bob plans to vote for Romney, then it’s likely that many of his friends are like-minded voters.

Weak Inductive Arguments:

1) On interviewing six students at the Union, it was found that four of them planned to spend the summer in Iowa, while two of them planned to go abroad.

2) Therefore, 33% of ISU students (probably) plan go abroad during the summer.

Problem: Sample size too small. Six students is too small a number to make predictions about the whole student body.

Abductive Arguments: “The world must be spherical in shape.  For the night sky looks different in the northern and southern regions, and this would be so if the earth were spherical.”   -Aristotle, Physics.

To put this argument in standard form, we might interpret it as follows:

(1) The night sky looks different in the northern and southern regions.(2) The best explanation for this fact is that the earth is round.(3) Therefore (probably) the earth is spherical in shape.

Evaluating Abductive Arguments:

Abductive arguments are stronger if the explanation posited in the conclusion is the only explanation that will adequately account for the phenomenon to be explained, or if it is the most likely of a small set of possible explanations.

Abductive arguments are weaker if there are many other plausible explanations that would account for the phenomenon, or if we have independent reason to believe that the explanation offered is unlikely.

Evaluating Abductive Arguments:

1) There is an odd and very loud banging sound coming from the classroom upstairs from our own.

2) If there were elephants up there, it would explain the sounds we hear.

3) There are elephants in the room upstairs from our classroom.

Evaluating Abductive Arguments:

Why is the argument weak?

1) There are many alternative explanations for the sounds we hear.

2) We have independent reason to doubt that there are elephants upstairs.

Evaluating Abductive Arguments:

When is an abuductive argument weak?1) When the explanation offered is only one of

many alternative explanations for the sounds we hear.

2) When alternative explanations are simpler, independently more plausible, or otherwise preferable to the explanation offered.

3) Where there is independent reason to doubt the offered explanation.

An Argument for Analysis

“People may seem to be kind, compassionate, or altruistic, but if you really search out the basis of their actions you will discover that they’re really behaving selfishly. Every voluntary action is motivated by the values of the actor herself. So in all of our voluntary actions, we are pursuing our own ends. Exclusively to pursue one’s own ends is to be selfish. So all of our voluntary actions are ultimately selfish.”

“People may seem to be kind, compassionate, or altruistic, but if you really search out the basis of their actions you will discover that they’re really behaving selfishly. Every voluntary action is motivated by the values of the actor herself. So in all of our voluntary actions, we are pursuing our own ends. Exclusively to pursue one’s own ends is to be selfish. So all of our voluntary actions are ultimately selfish.”

1) Every voluntary action is motivated by the values of the actor herself.

2) So in all of our voluntary actions, we are pursuing our own ends.

3) Exclusively to pursue one’s own ends is to be selfish.

Conclusion: All voluntary actions are selfish.

Some Theories of Human Action:

Psychological Egoism: All voluntary human actions are ultimately selfish.

Ethical Egoism: Actions are morally right if and only if they are selfish.

Evaluating Philosophical Arguments

(1) First Pass: First, read through the work rather quickly, noting difficult words, concepts and claims as you go. Make certain that you understand the main points the author is trying to make, and be sure to look up any unfamiliar or confusing terms or concepts. 

Evaluating Philosophical Arguments

(2) Read for Understanding: In your second pass through the material, you should read slowly and deliberately. Take notes. Make sure that you understand each of the arguments offered, and that you understand what reasons are given to support the conclusions the author hopes to support. Clarify the claims the author makes—make sure you understand what the author means.

Evaluating Philosophical Arguments

(3) Criticism and Objections: After you have finished reading the material carefully and have an understanding of the author’s arguments, evaluate the claims made and the evidence given. Articulate the strongest objections and counter-arguments you can develop: try to construct an argument against the position the author has defended.

Evaluating Philosophical Arguments

4) Re-Evaluation of the Argument: Finally, go back and read the text again, keeping in mind the objections you have raised and the counter-arguments you have developed. Does the author have resources to respond to your objections and counter-arguments? Are your objections conclusive, or are you inclined to accept the conclusion as well supported by the argument?

Example: Anselm O Lord, you who give understanding to faith, so far as you know it to be beneficial, give me to

understand that you are just as we believe , and that you are what we believe. We certainly believe that you are something than which nothing greater can be conceived.             But is there any such nature, since “the fool hath said in his heart: “God is not.”             However, when this very same fool hears what I say, when he hears of “something than

which nothing greater can be conceived,” he certainly understands what he hears.             What he understands stands in relation to his understanding (esse in intellectu), even if

he does not understand that it exists.  For it is one thing for a thing to stand in relation to our understanding; it is another thing for us to understand that it really exists.  For instance, when a painter imagines what he is about to paint, he has it in relation to his understanding.  However, he does not yet understand that it exists, because he has not made it.  After he paints it, then he both has it in relation to his understanding and understands that it exists.  Therefore, even if the fool is convinced that “something than which nothing greater can be conceived” at least stands in relation to his understanding, because when he hears of it he understands it, and whatever he understands stands in relation to his understanding.

            And certainly that than which a greater cannot be conceived cannot stand only in relation to the understanding.  For if it stands at least in relation to the understanding, it can be conceived to be also in reality, and this is something greater.  Therefore, if “that than which a greater cannot be conceived” only stood in relation to the understanding, then “that than which a greater cannot be conceived” would be something than which a greater can be conceived.  But this is certainly impossible.

            Therefore, something than which a greater cannot be conceived undoubtedly both stands in relation to the understanding and exists in reality.  (Saint Anselm, from Sober, p. 125)

ON TO PLATO!