Critical reasoning – is both active and open to alternative points of view
Passive reading/listening – writing down notes in lecture, you are passive in the sense that you don’t evaluate which statements to accept and which to reject and you don’t consider the speakers pattern of reasoning.
Mere disagreement – is both critical and active but is not open to alternative views. You enter with your own established beliefs already in mind.
Cooperative enterprise – two people have opposing views; one person sets his beliefs aside and help the other to strengthen his argument.
Critical reasoning misconceptions – it’s too rigid or linear, it supposes that there is a right and wrong point of view.
Argument – reasons for believing something or acting in a certain way

If the author is attempting to state what has happened, or what is the case, or what something is like, he is engaged in descriptive writing, not argumentation
If he is trying to prove something by giving reasons, he is engaged in argumentative writing.

Diatribe is bitter and violent criticism or invective
Examples of diatribe are often found in letters to the editor, in which people tend to give vent to their strong feelings instead of backing up their opinions with arguments. Consider the following (fictitious) letter: The politicians are at it again. An election coming up, and new spending just “happens” to be needed. Name your favourite issue, and you will find money for it—health care, education, social services. And tax cuts too? I don’t trust a single one of them. It is clear that the author of this letter believes that the new money allocated to social programs has more to do with an upcoming election than with real needs of the electorate, but she doesn’t give any reasons for this view.

Roughly speaking, explanations are answers to certain kinds of “why” or “how” questions, questions about why something happened or happens (why do humans walk on two legs?) or why something is the case (why are you so angry?) or how to do something (how do you download software?). Note that when we give explanations, we are not trying to prove that anything happens or that anything is the case. We already know that humans walk on two legs and that software can be downloaded. What we want to know is why or how.
This, then, is the difference between explanation and argument. When we give arguments, we are trying to prove or demonstrate something, whereas when we give explanations, we are trying to say why or how something that is already known (or thought to be known) to happen or to be the case happens or is the case. This distinction suggests that the best way to determine whether a passage contains an argument or an explanation is to ask yourself whether the author is trying to prove something or trying to get you to understand why something is the case or how something happens

Deductive argument - has a structure that makes the conclusion follow necessarily from the premises.
Ex. Eliminating plea bargaining would overwhelm the court system with criminal trials. If it would do this, then plea bargaining should not be eliminated. Therefore, plea bargaining should not be eliminated.

Inductive argument – the premise describes a characteristic found in a sample (50 cities). This conclusion asserts that it is likely this same characteristic is true of a larger population.

Argument from analogy – argues that two things are alike in certain respects so they are probably alike in some further respect.
Convergent argument – giving reasons that have some weight that doesn’t necessarily follow the conclusion.

Premise indicators – Since, For, Because, for the reason that

Conclusion indicators – So, Thus, Therefore, Hence, We can conclude that, Consequently

Premise conclusion indicators – shows that, indicates that, proves that, entails that, implies that, establishes that, allows us to infer that, gives us reasons for believing that

Conclusion premise indicators – is shown by, is indicated by, is proven by, is entailed by, is implied by, is established by

Principle of charitable interpretation – when more than one interpretation of an argument is possible, the argument should be interpreted so that the premises provide the strongest support for the conclusion.

Modus ponens Disjunctive argument Modus Tollens hypothical
If A then B either A or B if A then B if A then B
A not A not B if b then C
Therefore B therefore B Not A if A then C

An important difference between nondeductive and deductive arguments is that a good deductive argument conclusively proves its conclusion, whereas even if a nondeductive argument is as good as possible, its conclusion may turn out to be false

Nondeductive indicator words : “it is possible that,” “likely,” “I think that,” and so on.

deductive use the expressions “necessarily,” “must,” and “know.”

Definition of validity: If the conclusion of a deductive argument follows from its premises, the argument is said to be valid. If not, it is said to be invalid.

3) All cats are mammals.
All dogs are mammals.
Therefore, all cats are dogs.

This is not a valid argument, because its conclusion does not follow from its premises. In this case, it is very easy to see that the conclusion does not follow from the premises because, although the premises are true, the conclusion is false. Hence, the truth of the premises does not guarantee the truth of the conclusion

It need not always be the case that an invalid argument has true premises and a false conclusion. In fact, the validity or invalidity of an argument is independent of the truth or falsity of its premises. Validity depends upon the form or structure of an argument. When we say that an argument is invalid, we are saying that it has a faulty structure, we are not making reference to the truth or falsity of its premises. To illustrate the independence of the validity or invalidity of an argument and truth or falsity of its premises, we give the following argument: (4) Cats are feline. Dogs are canine. Therefore, dogs are animals. This argument has true premises and a true conclusion, but it is invalid because the conclusion does not follow from the given premises—the premises do not help to prove the conclusion

a valid argument cannot have true premises and a false conclusion. This is because if the premises of an argument are true and the conclusion follows from the premises (i.e., the argument is valid), the conclusion must be true as well.

Valid argument If A, then B If A then B
If B, then C A
A Therefore, B
C

Invalid

If A, then B If A then B If A then B if B, then C Not A B
C Therefore, not B Therefore, A
A

Definition of soundness: A valid deductive argument whose premises are all true is said to be sound.

Equivocation: when an expression whose meaning is unclear is used in more than one premise, its meaning might shift from one premise to the next. If this happens, the usual result is that the conclusion does not follow from the premises.

Vague: When there is no definite boundary between the objects and expression applies to and those to which it does not, the expression is vague. Ex. Tall, there is no definite boundary between ppl who are tall and those who are not.

Ambiguity: an ambiguous expression has more than one meaning. Ex. A pen and pen (pig pen)

Quantity and Quality
A categorical proposition may be either affirmative (as in “All ravens are black”) or negative (as in “Some birds are not feathered”). The quality of a proposition is either affirmative or negative. Types A and I are affirmative, types E and O are negative. It is thought that the letters “A” and “I” were assigned to the affirmative propositions from the Latin word “affirmo” (I affirm) and “E” and “O” to the negative propositions from “nego” (I deny). The quantity of a proposition answers the question, “How many?”
All categorical propositions are used to assert something about all or some of a certain kind of thing. Universal propositions are those we use to assert something about all of them. Types A and E are universal. Particular propositions are those we use to assert something of some things of a certain kind. Types I and O are particular. The table below indicates the quality and quantity of categorical propositions.

The type, structure, quality, and quantity of our snake example are summarized in the table below.

Example Type Structure Quantity and Quality
All snakes are slimy. A All S’s are P Universal Affirmative
No snakes are slimy. E No S’s are P Universal Negative
Some snakes are slimy. I Some S’s are P Particular Affirmative
Some snakes are not slimy. O Some S’s are not P Particular Negative

Exercise 1
Follow the instructions below for Unit 4 Exercise 1.

Instructions
Identify the subject and predicate terms of the following categorical propositions, and state their quantity and quality. Answers are provided at the end of the exercise.

Sample Proposition
All beavers are industrious.

Answer
Subject term: beavers
Predicate term: industrious
Quantity and quality: universal affirmative

Exercise Questions
1. Some leadership candidates are supporters of French language rights. 2. No former employees are eligible for company benefits.
3. Some tax deductions are not easy to justify.
4. All models that have all available options are easy to interest people in, but hard to sell.
5. No models are interesting to all potential buyers.
Answers to Exercise 1
1. Subject term: leadership candidates
Predicate term: supporters of French language rights
Quantity and quality: particular affirmative
2. Subject term: former employees
Predicate term: eligible for company benefits
Quantity and quality: universal negative
3. Subject term: tax deductions
Predicate term: easy to justify
Quantity and quality: particular negative
4. Subject term: models that have all available options
Predicate term: easy to interest people in, but hard to sell
Quantity and quality: universal affirmative
5. Subject term: models
Predicate term: interesting to all potential buyers
Quantity and quality: universal negative

Syllogisms
Let us now state the definition of a syllogism. A syllogism is a deductive argument that consists of three categorical propositions containing a total of three terms, each of which appears in two different propositions. Two of the propositions are premises and one is the conclusion.

Another example of a syllogism is given below.
(1) All bachelors are lonely people.
(2) Some lonely people are drifters.
(3) Therefore, some bachelors are drifters.

Quantity and Quality

A categorical proposition may be either affirmative (as in “All ravens are black”) or negative (as in “Some birds are not feathered”). The quality of a proposition is either affirmative or negative. Types A and I are affirmative, types E and O are negative. It is thought that the letters “A” and “I” were assigned to the affirmative propositions from the Latin word “affirmo” (I affirm) and “E” and “O” to the negative propositions from “nego” (I deny).

The quantity of a proposition answers the question, “How many?” All categorical propositions are used to assert something about all or some of a certain kind of thing. Universal propositions are those we use to assert something about all of them. Types A and E are universal. Particular propositions are those we use to assert something of some things of a certain kind. Types I and O are particular. The table below indicates the quality and quantity of categorical propositions.

Example Type Structure Quantity and Quality

All snakes are slimy. A All S’s are P Universal Affirmative
No snakes are slimy. E No S’s are P Universal Negative
Some snakes are slimy. I Some S’s are P Particular Affirmative
Some snakes are not slimy. O Some S’s are not P Particular Negative

Exercise 1 Follow the instructions below for Unit 4 Exercise 1.

Instructions

Identify the subject and predicate terms of the following categorical propositions, and state their quantity and quality. Answers are provided at the end of the exercise.

Sample Proposition
All beavers are industrious.

Answer
Subject term: beavers
Predicate term: industrious
Quantity and quality: universal affirmative

Exercise Questions
1. Some leadership candidates are supporters of French language rights. 2. No former employees are eligible for company benefits.
3. Some tax deductions are not easy to justify.
4. All models that have all available options are easy to interest people in, but hard to sell.
5. No models are interesting to all potential buyers.

Answers to Exercise 1
1. Subject term: leadership candidates
Predicate term: supporters of French language rights
Quantity and quality: particular affirmative
2. Subject term: former employees
Predicate term: eligible for company benefits
Quantity and quality: universal negative
3. Subject term: tax deductions
Predicate term: easy to justify
Quantity and quality: particular negative
4. Subject term: models that have all available options
Predicate term: easy to interest people in, but hard to sell
Quantity and quality: universal affirmative
5. Subject term: models
Predicate term: interesting to all potential buyers
Quantity and quality: universal negative

Venn Diagrams
The method we are about to learn for testing syllogisms for validity, invented by the nineteenth-century British philosopher, John Venn, can be used to show whether any given syllogism is valid or invalid.
Venn diagrams express in graphic form the claims made in categorical propositions. We use three overlapping circles, one for each term of the syllogism. We can express the meaning of certain propositions on this diagram. (Note that we are not concerned with the truth or falsity of our examples, but only with representing their meaning on our diagrams.) To understand how they work, consider first the following diagram: Let us first see what would be in each of the seven areas created by this diagram, the circles of which are labelled “S,” “P,” and “M” for
“Snakes,” “Poisonous,” and “Malicious,” respectively.
Area 1: All snakes that are neither poisonous nor malicious.
Area 2: All poisonous, non-malicious snakes.
Try to identify what would be in areas 3 through 7.
Did you write:
Area 3: All poisonous things that are neither snakes nor malicious.
Area 4: All malicious, non-poisonous snakes.
Area 5: All malicious, poisonous snakes.
Area 6: All poisonous, malicious things that are not snakes.
Area 7: All malicious things that are neither snakes nor poisonous.

Universal Categorical Propositions
Let us now see how to diagram categorical propositions on our threecircle diagrams. Let’s suppose that we wanted to diagram “All M is P.”
Since it is a universal premise we will be shading in some area of the
Venn diagram. The M circle contains all M’s and the P circle contains all things with the property or characteristic P (say, “poisonous”). The M and P circles are drawn overlapping because some things might be both M and P. For now just focus on the M and P circles and ignore the
S circle. Since “All M is P” is a universal categorical proposition we must
16 Philosophy 252 / Study Guide I, Unit 4 shade in some area of the circle and remember by shading something in we are indicating that that area is empty. What would we shade in to indicate “All M is P”? “All M is P” would be diagrammed as:

As you can see, you diagram “All M is P” by shading in all of the M circle except where it intersects with the P circle. The intersection of the M and P circle is the area where all M’s have the property or characteristic
P. By shading in all of the M circle (area 4 and 7) except the intersection of the M and P circles (area 5 and 6), you indicate that all of the M’s that you have must have the property or characteristic of being P, i.e., we don’t have any M’s that fail to have the property P. This is precisely the meaning of “All M is P.” Don’t be concerned that part of the S circle is shaded in (area 4).
Try to diagram “All S is P” and “All P is M” on the following diagrams:

“No P is S” would be diagrammed as:

Particular Categorical Propositions
We have two particular categorical propositions: “Some S is P” and
“Some S is not P.” To diagram these we put an “x” somewhere on the
Venn diagram. First, let us look at “Some S is P,” which is an Iproposition.
How can we indicate the exact meaning of I-propositions (e.g., “Some S is P”) on three-circle diagrams? Where should we place the “x” in the following diagram to indicate the meaning of “Some S is P”? If we place it in area 1, we indicate that some S is both P and M, which is not indicated by “Some S is P.” If we place the “x” in area 2, we indicate that some S is P but not M, but this is not indicated by “Some S is P” either. We have simply not been given any information about whether or not any S is M when we are told that some S is P. We solve this problem by placing the “x” on the line between areas 1 and 2 to indicate that we do not know which of areas 1 and 2 the “x” is in.

Use these tips to diagram “Some P is S” and “Some M is P”:

Formal fallacies are kinds of arguments involving invalid argument forms that nevertheless often appear valid; they are persuasive when they should not be. Two of the most common formal fallacies, “affirming the consequent” and “denying the antecedent

informal fallacies, fallacies that involve not the form of arguments but their content
A fallacy is a bad argument that tends to persuade us even though it is faulty
Distraction fallacies: False Dilemma : It presents and either or choice when in fact there are more alternatives. Ex: either we legalize drugs, or we keep building new prisons and filling them up Slippery Slope : Sometimes we object to something on the grounds that if it is done, then something else will happen, and if so then something else will happen. When it is a fallacy, one of the if-then premises will be doubtful. Straw man : consists of making your own position appear strong by making the opposing px appear weaker than it actually is. Ex: We should ban all guns. Those who oppose a ban on guns don’t think very many crimes involve guns, but statistics prove otherwise.

Resemblance fallacies: Affirming the consequent : if A then B, B, therefore A Denying the antecedent : if A then B, Not A, therefore Not B Equivocation : an arugment in which an expression shifts its meaning from one premise to another, making the pattern invalid. Ex. Insane ppl shouldn’t be punished. Someone who commits a murder must be insane. So murderers should not be punished. Begging the question : an argument resting on a premise that is either a restatement of the conclusion or that would be doubted for the same reasons that the conclusion would be doubted.
Ex. The bible says god exists. Everything in the bible is true since god wrote it. So god does exist

Emotion fallacies: Appeal to authority : appealing to someone whose expertise is not relevant to the issue at hand or appealing to someone who is famous or admired but not an expert on the issue at hand. Ex. A majority of doctors think that the morality of young ppl has declined. Attacking the person : arguing that a persons point of view should be doubted because the person has bad traits of character or because the person has something to gain by being believed.
Ex. Most of the ppl who want drugs legalized are closet users. Prejudicial Language : an argument can also provide a motive for belief without providing support for belief by using prejudicial language. Ex. “I hope you aren’t going to say that you support the backward philosophy of emphasizing basic skills in primary and secondary education. I tend to take the progressive view that there are many things at least as important for students to learn as reading writing and arithmetic.
Ex. Chris outgrew the naïve view of human beings as mechanistic robot like creatures and came to the more sophisticated view of human beings as autonomous and possessing a will.
Identifying a px using words as backward or naïve provides a motive for rejecting the position and using words as progressive and sophisticated provides a motive for adopting a position all without giving any evidence either for the arguer’s px or against and opponent’s px.

Classification of Nondeductive Arguments

1. Inductive generalizations (particular to general) are arguments that proceed from facts or purported facts about particular individuals to a general statement about all, most or a certain percentage of individuals of that type. The following statement is an example of an inductive generalization.

“There is no overestimating the importance of pets to people, it seems. Katcher [a psychiatrist studying bonding between humans and pets] reported that in one questionnaire, on which people were given the opportunity to indicate whether they thought their pet was an animal or human member of the family, 48 percent responded that the animal was a human family member. (Holden, p. 418.)”

The author draws a general conclusion about the importance of pets from the results of a questionnaire completed by an unspecified number of people. (We will examine statistical fallacies and the use of statistics in argumentation more thoroughly in Unit 7.) Arguments from the particular to the general are sometimes called “sampling arguments,” “simple induction,” “induction by enumeration,” or “statistical generalization,” instead of “inductive generalization.”

Inductive generalizations are also used to draw conclusions about what will happen in the future on the basis of what has happened in the past: That a stone will fall, that fire will burn, that the earth has solidity, we have observed a thousand and a thousand times; and when any new instance of this nature is presented, we draw without hesitation the accustomed inference.

2. Statistical Syllogisms (general to particular) are arguments that draw the conclusion that an individual of a certain sort is likely to have a certain property because most individuals of that sort have that property. “Most people like chicken, so the Smiths will probably like a chicken dinner,” is an example of a statistical syllogism. If we do not know anything about our guests’ food preferences, we fall back on our knowledge of what most people like, or at least do not strongly dislike.
Criticisms of arguments with statistical premises. 1. Attacking the premises 2. Noting that the number of premises dilutes the strength of the conclusion 3. Pointing out the total available evidence was not used.

3. Causal Arguments attempts to establish that one thing causes another. The following quote contains an example of causal argument. It is interesting to note that one of the frequent symptoms of extreme combat anxiety cases is an interference with speech that may run from complete muteness to hesitation and stuttering. . . . Similarly, the sufferer from acute stage fright is unable to speak. Many animals tend to stop vocalizing when frightened, and it is obvious that this tendency is adaptive in preventing them from attracting the attention of their enemies. In the light of this evidence one might suspect that the drive of fear has an innate tendency to elicit the response of stopping vocal behavior. (Dollard and Miller, p. 203) In this passage, the authors argue, on the basis of several observed correlations between fear and inability to speak, that fear may inhibit the ability to vocalize.

4. Analogy Arguments from analogy conclude that a certain thing has a certain property because something else, to which it is similar, has that property. Teaching children has long been compared to cultivating plants, and conclusions about what form teaching should take are often drawn on the basis of this comparison. Here is an example of such an argument, taken from an interview with Dr. Benjamin Spock: “
I think some of our schools should be less rigid than they still are and that teachers should not oppress their pupils in an Critical Thinking 9 authoritarian spirit as some of them still do. Yet it is essential for teachers to make clear what they expect of children. This is like giving a vine a pole on which to grow. (Shane, pp. 16–17)”

Although Dr. Spock does not state his argument completely, we can tell that he is drawing his conclusion that teachers should make their expectations clear to children on the basis of a comparison between the development of children and the development of vines.

5. Convergent Arguments are those that draw a conclusion on the basis of two or more independent premises, each of which is supposed to give some support. An argument we looked at in Unit 2 is an example of a convergent argument: This is not a good house to break into because the lights are on, there is a dog barking, there is a burglar alarm system, and it is right across the street from a police station.

list of criteria for evaluating empirical generalizations.

1. Truth of premises: Are the premises true? Have the data been misinterpreted?
2. Missing data: Have any relevant data, which the reasoner could and should have included, been left out?
3. a. Size of sample: Have enough cases been observed? (Has the reasoner committed the fallacy of hasty generalization?) b. Representativeness: Are the cases examined representative of the type of thing being generalized about? (Has the reasoner committed the fallacy of biased statistics?)
4. Strength of conclusion relative to premises: Is the conclusion too strong or too weak for the support given to it by the premises?
5. Truth of conclusion: Are there counterinstances of, or counterevidence to, the conclusion?
6. Consistency in unit analysis: Has the author shifted between one unit of analysis in the premises and another on the conclusion?

If you keep even some of these criteria in mind, you will find yourself actively questioning more of what you read.
For example, the Greenpeace organization experimented with a device, consisting of a series of nets raised into the air by helium-filled balloons, designed to interfere with the testing of the cruise missile. In a newspaper article about the experiment, the author said, “Most people in the Athabasca region were amused by the tests rather than impressed” (Geisinger, p. 1). If you are reading critically, you will ask yourself, “How does the author know?” As you read on, you find that the only evidence given is a quotation from one observer. The author does not provide enough information to enable you to evaluate his reasoning, but you should ask yourself whether he is likely to have questioned enough people whose opinions are representative of the majority of people in the region to justify that statement. This simple example is meant to show that we can often protect ourselves from forming questionable impressions without specialized, technical knowledge. Note that we are not saying that the author’s statement is false, but that we will withhold assent from it, because it is insufficiently substantiated. You will get a chance to practise applying the above criteria in the exercise below.

Bias and prejudice involve either applying false generalizations—often about how members of a race, sex, or ethnic group can be expected to behave—to individual people, or applying generalizations which may be true for the most part, to individuals, without considering whether they might be exceptions to the general rule.

Causal arguments move from a premise that two things are associated or correlated to a conclusion that the first is not merely correlated with but causes the second.
Ex. Exposure to high levels of secondhand smoke is correlated with lung cancer
Concl : exposure to high levels of secondhand smoke causes lung caner.
Ways in which causal reasoning might fail
1. the correlation might be coincidental.
2. The items might be correlated because they are both effects of the same underlying cause. (spurious)
3. the causal relation might be genuine but insignificant.
4. the causal relation might be in the wrong direction.
5. The causal relation might be complex.
6. What is cited as the cause may be only part of the cause. For example, your son may be doing badly in school both because he cannot see the blackboard properly and because he was switched from one class to another. It is important to identify both problems, because, if steps are taken to remove only one cause, there may be no improvement.