This document defines and discusses different types of arguments and logical fallacies. It begins by defining deductive and inductive arguments, and explaining how to identify them based on language used. Common types of deductive and inductive arguments are then outlined. The document also discusses the concepts of validity, soundness, and strength as they relate to arguments. Finally, it provides detailed descriptions and examples of many common logical fallacies, categorizing them as fallacies of relevance, weak induction, ambiguity, analogy, or formal fallacies.
1.1 arguments, premises, and conclusionsSaqlain Akram
Formal Logic : Leacture 01
Chapter 1: Basic Concepts
1.1 Arguments, Premises, and Conclusions
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1.1 arguments, premises, and conclusionsSaqlain Akram
Formal Logic : Leacture 01
Chapter 1: Basic Concepts
1.1 Arguments, Premises, and Conclusions
Follow on Facebook:
https://web.facebook.com/learnforgood...
and on Youtube:
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Also Subscribe For More Videos.
Learn For Good.
With a view to employing logic appropriately we should be aware of logical fallacies we might commit. Some are common and unintentional , others are deliberate .Some are tricks to win an argument, others are simply immoral and should be avoided.
With a view to employing logic appropriately we should be aware of logical fallacies we might commit. Some are common and unintentional , others are deliberate .Some are tricks to win an argument, others are simply immoral and should be avoided.
Understanding arguments, reasoning and hypothesesMaria Rosala
As researchers working in government, influencing service design, we need to know that our research is methodologically sound, our research findings are grounded in empirical data and our recommendations are logically derived.
'Understanding arguments, reasoning and hypotheses' is the first in a series of 5 short courses, covering introduction courses to various aspects of methodology in research, from the use of grounded theory in discovery research, to hypothesis testing and sampling in more experimental research.
In this course, you'll learn:
About arguments
- what we mean by an argument
- how to identify a valid/invalid argument
- what we mean by premises
- what validity and soundness of arguments mean
About reasoning
- what is deductive reasoning and where do we use it
- what is inductive reasoning and where do we use it
- what is abductive reasoning and where do we use it
About hypotheses
- what is a hypotheses and a null hypothesis
- how do we test them
Deductive Argument
For a deductive argument, if all its premises are true, its conclusion is necessarily true (or it is logically impossible for the conclusion to be false.)
I.e., the truth of premises guarantees the truth of conclusion.
Example
Either you work hard or you will fail the test.
You do not work hard.
Therefore, you will fail the test.
3 Types of Possibility
Technological possibility:
e.g.
Going to the moon is technological possible, but going to Mercury is not.
Physical possibility:
e.g.
Going to Mercury is physical possible, but making water boil at 95 C under one atmospheric pressure is not.
Logical possibility:
e.g.
Making water boil at 95 C under one atmospheric pressure is logical possible, but drawing a triangle with 4 angles is not.
When we talk about deductive arguments, we have already presupposed that the arguments are successful or valid deductive arguments.
The conclusion of a valid argument is called a valid conclusion.
For an unsuccessful deductive argument (the premises are intended to guarantee the conclusion but fail to do so), we call it an invalid argument.
A deductive argument may be valid or invalid, there is nothing in between.
Whether a deductive argument is valid or invalid depends on its form or structure, not on its content.
The above argument is valid because it has this valid form:
p or q.
Not-p.
Therefore, q.
p and q are statement variables.
A valid argument may have false conclusion if it has false premises.
Example:
CY Leung is either a genius or an idiot.
He is not an idiot.
Therefore, He is a genius.
In order to guarantee the truth of conclusion, we have to make sure all the premises are true.
When all the premises of a valid argument are true, the argument is called a “sound argument”.
And the conclusion of a sound argument is called a sound conclusion.
If an argument is invalid or has false premises, it is unsound.
On the other hand, the fact that an argument is invalid does not entail that its conclusion is false.
• It just means that its conclusion does not follow from its premises.
• You can consider a valid argument structure as a truth-keeping machine:
• When you input T information into it, it will output T information.
• When you input F information into it, it will output T or F information
Inductive Argument:
A typical example of inductive argument:
Swan1 is white.
Swan2 is white.
Swan3 is white.
…
Swann is white.
________________
All swans are white.
Another typical example:
An event of type B follows an event of type A at time t1.
An event of type B follows an event of type A at time t2.
…
An event of type B follows an event of type A at time tn.
___________________________
A causes B.
Many people think that the characteristic of inductive arguments is arguing from particular to general.
However, deductive arguments may also argue from particular to general.
Example:
I have two cats, Fluffy and Garfield.
Fluffy does not eat fish.
Garfield does not eat fish either.
Therefore, All of m
4 Mistakes in Reasoning The World of Fallaciesboy at chalkboar.docxgilbertkpeters11344
4 Mistakes in Reasoning: The World of Fallacies
boy at chalkboard, puzzled at two math equations, 2+2=4 and 3+3=7
Have you ever heard of Plato, Aristotle, Socrates? Morons!
—Vizzini, The Princess Bride
So far we have looked at how to construct arguments and how to evaluate them. We've seen that arguments are constructed from sentences, with some sentences providing reasons, or premises, for another sentence, the conclusion. The purpose of arguments is to provide support for a conclusion. In a valid deductive argument, we must accept the conclusion as true if we accept the premises as true. A sound deductive argument is valid, and the premises are taken to be true. Inductive arguments, in contrast, are evaluated on a continuous scale from very strong to very weak: the stronger the inductive argument, the more likely the conclusion, given the premises.
What We Will Be Exploring
We will look at mistakes in reasoning, known as fallacies.
We will examine how these kinds of mistakes occur.
We will see that errors in reasoning can take place because of the structure of the argument.
We will discover that different errors in reasoning arise due to using language illegitimately, requiring close attention be paid to that language.
Generally, we want our arguments to be "good" arguments—sound deductive arguments and strong inductive arguments. Unfortunately, arguments often look good when they are not. Such arguments are said to commit a fallacy, a mistake in reasoning. Wide ranges of fallacies have been identified, but we will look at only some of the most common ones. When trying to construct a good argument, it is important to be able to identify what bad arguments look like. Then we can avoid making these mistakes ourselves and prevent others from trying to convince us of something on the basis of bad reasoning!
4.1
What Is a Fallacy?
image
The French village of Roussillon at sunrise. Roussillon is in Vaucluse, Provence. It would be a fallacy to assume that because someone lives in France, he or she lives in Paris.
Most simply, a fallacy is an error in reasoning. It is different from simply being mistaken, however. For instance, if someone were to say that "2 + 3 = 6," that would be a mistake, but it would not be a fallacy. Fallacies involve inferences, the move from one sentence (or a set of sentences) to another. Here's an example:
If I live in Paris, then I live in France.
I live in France.
Therefore,
I live in Paris.
Here, we have two premises and a conclusion. The first sentence is a conditional, and we can accept it as true. Let's assume the second sentence is also true. But even if those two premises were true, the conclusion would not be true. While it may be true that if I live in Paris then I live in France, and it may be true that I live in France, it does not follow that I live in Paris, because I could live in any number of other places in France. Thus, the inference from the .
Week 14 April 28 & 30 - Love and Death Castillo, Chap. 9 .docxmelbruce90096
Week 14: April 28 & 30 - Love and Death
Castillo, Chap. 9 “Sofia, Who Would Never Again Let Her Husband Have the Last Word…”
Chap. 10 “Wherein Sofia Discovers La Loca’s Playmate…”
Chap. 11 “The Marriage of Sofia’s Faithful Daughter to her Cousin”
Chap. 12 “Of the Hideous Crime of Francisco el Penitente…”
1. For all chapters, identify the four levels of analysis: 1) metaphoric/symbolic; 2) literary; 3) sociological; and spiritual.
Chapter 9 “Sofia, Who Would Never Again Let Her Husband Have the Last Word…”
2. In this chapter, Sofia begins a transformation of her own. What is this transformation and what role does Esperanza play?Chapter 10
3. In this chapter, we return to La Loca, reading from her point of view. What do we learn from this, the youngest of Sofi’s daughters?
4. As Fe leaves Sofia’s home we realize she has not come to terms with what she went through when Tom broke off the engagement. What is Fe like now? Has she also changed?
5. What about Esperanza, what news about her? And what about “La Llorona, Chicana international astral-traveler”?
Chapter 11
6. Much happens to Fe in this chapter. Be able to recount all of Fe’s experiences and the relationship to big business, the U.S. government, and the medical profession.Chapter 12
7. What to make of this last chapter in Caridad and Francisco’s lives? What are the recurring themes and metaphors/symbolizes, etc.?
In preparation for the Opposing Viewpoints short paper due in Module Five, you will outline a position (thesis) on a topic of your choosing.
Using the Prewriting Template provided, outline two to three of your reasons for supporting your thesis and then also outline the objection’s position. Please note that the main purpose of this assignment is to formulate the strongest possible objection to your own position before responding to it.
You will be required to use at least four outside (i.e., other than the textbook) sources for this paper, two for each side of the issue. You do not need to do extensive reearch before completing the outline.
Possible topics: Affirmative Action, Abortion, State-Financed Health Care, Flat Tax...or anything you want. It is best to choose a position for which you can find reasonable arguments on both sides.
Click on the title above to turn in your outline.
First Paper (Opposing Viewpoints):
Critical Elements
Distinguished
Proficient
Emerging
Not Evident
Value
Main Elements
Includes almost all of the main elements and requirements and cites ample appropriate support to illustrate each element
(23-25)
Includes most of the main elements and requirements and cites appropriate support to illustrate each element
(20-22)
Includes some of the main elements and requirements
(18-19)
Does not include any of the main elements and requirements
(0-17)
25
Inquiry and Analysis
Explores multiple reasons and offers in-depth analysis of evidence to make informed conclusions about the issue
(18-20)
Explores so.
3. Arguments Logic(def.): The science that evaluates arguments. Argument (def.): A group of statements, a group of which serve (the premises) to support, imply, or provide evidence for another statement. (the conclusion). Premises (def.): Set forth the reasons for the conclusion. Logic--The primary task: To distinguish between good arguments and bad arguments. A good argument is one in which the premises support the conclusion.
4. “BarBarA” Socrates is a man. Premise All men are mortal. Premise Therefore, Socrates is mortal. Conclusion
5. Types of Arguments 1. Deductive Argument (def.): When an argument has the purport of proving its conclusion necessarily from the premises. An argument is deductive if its purport is that it is impossible that its premises be true and its conclusion false. 2. Inductive Argument (def.): When an argument has the purport of showing its conclusion to be likely or probable given the premises. An argument is inductive if its purport is merely that it is improbable that its premises be true and its conclusion false.
6. Arguments: How to Identify Properties of Deductive Arguments: The conclusion follows, or thought to follow necessarily from the premises. In drawing its conclusion, the argument employs such words as “necessarily,” “certainly,” or “absolutely,” it is usually best regarded as deductive. Properties of Inductive Arguments The words such as “probably,” “likely,” or “plausibly” are employed.
7. Argument Types Deductive Arguments (types): Categorical Syllogisms (e.g., All N’s are x; S is an N; S is an x). Hypothetical Syllogisms (e.g., If P then Q; P, therefore Q). Disjunctive Syllogisms (e.g., Either C or T; Not S, therefore T). Inductive Arguments (types): Predictions about the future. Arguments from analogy. Inductive generalizations. Many arguments from authority. Arguments based on signs, and causal inferences.
8. Validity and Soundness Validity: A deductive argument is either valid or invalid. A deductive argument is valid if the conclusion follows necessarily from the premises: If it is necessarily the case that if the premises were to be true, then the conclusion must true (whether it is in fact true or not). If there is any possibility that the all the premises could be true and the conclusion false, the argument is invalid. NOTE: The truth of the premises is not required for validity.
9. Strength and Cogency Strong Inductive Argument: If on the basis of the assumption that its premises are true, its conclusion probably is true; otherwise, it is weak. Strength admits of degrees. A : Ninety percent of the mice in Australia have been examined and found to be white; therefore probably all of the mice in Australia are white. B: Ninety nine percent of the mice in Australia have been examined and found to be white; therefore, probably all of the mice in Australia are white. Both A. and B. are Strong, but B is even stronger than A. Cogent argument: is an inductive argument that is strong and has all true premises. The conclusion will probably also be true.
10. Fallacies A fallacy is a defect in an argument other than its having false premises. Types: Informal Fallacy: A fallacy that requires an analysis of the content of the argument and not just an inspection of its form. Formal Fallacy: A fallacy that may be identified by a mere inspection of the form of the argument.
11. Fallacies of Relevance The appeal to force (argumentum and baculum) occurs when the arguer, instead of providing genuine evidence for a conclusion, provides some sort of threat of harm to the listener or reader if the conclusion is not accepted. E.g., Either you can pay me you the ten thousand you owe me, or you can pay your dentist. The appeal to pity (argumentum ad misericordiam) occurs when the arguer, instead ofprovidinggenuine evidence for a conclusion, attempts to get the conclusion accepted by evoking pity from the listener or reader. E.g., Our company is on the rocks, financially, if you sue us, we will go out of business, and our children will not be able to go to college.
12. Fallacies of Relevance (cont.) The appeal to the people (argumentum ad populum) when the arguer tries to get the conclusion accepted by playing upon the listener’s desire to be loved, esteemed, admired, valued, recognized, or accepted. E.g., Everybody knows that Smith cannot win, so you should vote for Connor in the election. Argument against the person (argumentum ad hominem) when one arguer directs attention to the person of a second arguer and not to the second arguer’s argument or position. E.g., You graduated with a PhD from NYU, I’m surprised that you don’t believe that humans are responsible for climate change!
13. Fallacies of Relevance (cont.) Fallacy of accident: When a general rule is wrongly or unjustifiably applied to a specific case. E.g., Dogs have four legs; Fido just had one of his legs amputated; so Fido is not a dog any more. Straw man fallacy: When an arguer distorts a certain argument or position for in order to attack it, refutes the distorted argument or position, and then concludes that the real argument or position has been refuted. E.g., The Bible should not be taught in schools, because that’s what religious zealots want,
14. Fallacies of Relevance (cont.) Fallacy of Missing the Point(ignoratioelenchi) occurs when the premises of an argument lead, or seem to lead, to one conclusion and then a completely different conclusion is drawn. E.g., Abuse of the welfare system is rampant nowadays. Our only alternative is to abolish the system altogether. Red HerringFallacyis similar to the fallacy of missing the point. It occurs when an arguer diverts the attention of the reader or listener by going off on extraneous issues and points but ends by assuming that some conclusion relevant to the point at hand has been established. E.g., Our twelve year old boys are failing in mathematics. I just discovered that they were looking at pornographic websites last night. So you need to learn how to keep tabs on their Internet use!
15. Fallacies of Weak Induction Unqualified Authority (argumentum ad verecundiam): When an arguer cites the testimony or belief of an authority who is not necessarily reliable or who is not an expert in the subject at hand. E.g., He has a PhD in Physics, that makes him a doctor, so we should ask him if I have Swine Flu! Appeal to ignorance (argumentum ad ignorantiam): When the premises state that nothing is known with certainty about a certain subject, and the conclusion states something definite about that subject. E.g., People have been trying for centuries to disprove the claims of astrology. But no one has ever succeeded. So astrology is just nonsense.
16. Fallacies of Weak Induction (cont.) Hasty Generalization(converse accident):When a conclusion is drawn about all the members of a group or population from premises about some sample of the group that is not representative. E.g., When I wore this copper bracelet, I broke out into a rash. I must be allergic to copper. False Cause:When the link between premises and conclusion in an argument depends on the supposition of some causal connection that does not in fact exist. E.g.,: The clock chimed six times, and then the sun came up; the sun would not have come up without the clock chiming six times.
17. Fallacies of Weak Induction (cont.) Slippery Slope: When the conclusion of an argument depends on the claim that a certain event or situation will ultimately lead to an undesirable consequence, without justification. E.g., If we start letting newspapers publish their news online, then one of these days there will be no more newspapers and the news industry will become obsolete. Weak analogy: When the analogy between two things is not strong enough to support the conclusion; sometimes it is a lack of causal connections between the attributes. E.g., A has attributes a, b, c, d, and z; B has attributes a, b, c, and d; So B probably has z.
18. Fallacies of Weak Induction (cont.) Begging the Question (petitioprincipii) When the arguer uses some trick or device to hide the fact that a premise may not be true. E.g., If it weren’t for Global Warming, we wouldn’t be suffering from four weeks of 85 degree-plus weather in September. Complex Question When an apparently single question is asked that really involves two or more questions, answerable by single answer. E.g., Have you stopped drowning kittens for fun?
19. Fallacies of Ambiguity Fallacy of Suppressed Evidence Consists in passing off what are at best half-truths as if they were the whole truth and using them as premises in an argument. E.g., You ought to learn to play golf, because executive assistants make excellent money and acquire great perks. Fallacy of Equivocation When the inference in an argument depends on the fact that a word or phrase is used in two or more different senses. E.g., Banks have lots of money in them; the sides of rivers are banks; therefore, the sides of rivers have lots of money in them.
20. Fallacies of Ambiguity (cont.) Fallacy of Amphiboly: When an arguer, beginning with some statement that is ambiguous owing to its syntactical structure, proceeds to interpret it in a way in which it was not intended and to draw a conclusion based on this faulty interpretation. E.g., Last night Scott cuddled his dog in his pajamas. Why Scott put the dog in his pajamas I’ll never know. A False Dichotomy A pair of alternatives, presented as if it were a dichotomy when it is not in fact a dichotomy. E.g., You can ride the bus, or you can take your lunch.
21. Fallacies of Analogy Fallacy of Composition: When the inference in an argument depends on the erroneous transference of a characteristic from the parts of something to the whole. E.g., Hydrogen and Oxygen are gases; therefore, H2O is a gas. Fallacy of Division When the inference in an argument depends on the erroneous transference of a characteristic from a whole to some one or more of its parts. E.g., Salt is a non-poisonous compound. Therefore, it’s component elements, sodium and chlorine, are non-poisonous [FALSE]
22. Formal Fallacies Fallacy of Affirming the Consequent:Consists of one conditional premise, a second premise that asserts the consequent of the conditional, and a conclusion that asserts the antecedent. For example: a. If Napoleon was killed in a plane crash, then he is dead. b. Napoleon is dead. c. Therefore, Napoleon was killed in a crash. This fallacy has the form: If P then Q Q, so P.
23. Formal Fallacies (cont.) The Fallacy of Denying the Antecedent: Consists in a conditional premise, a second premise that denies the antecedent of the conditional, and a conclusion that denies the consequent: a. If Napoleon was killed in a plane crash, then Napoleon is dead. b. Napoleon was not killed in a plane crash. c. Therefore, Napoleon is not dead. This fallacy has the form If P then Q. Not Q, so not-P.