**Constructing an Argument** - Arguments will succeed or not succeed depending on - how well they are constructed; and - how strong their reasoning forms are **Critical Reasoning** - *Valid Arguments* - ![[Pasted image 20240125143045.png]] - *The Counterexample* - A logically possible case in which the argument's conclusion could be imagine to be false while the argument's premises are assumed to be true - However, just because an argument is shown to be invalid does not mean that the argument’s conclusion is false. If the argument is invalid, all we are sure of is that the logic shown does not guarantee that the conclusion must be true. - *Strength of an Argument* - Are the argument’s premises true in the actual world? - Arguments can be valid in terms of logical form but still be unsound. - To be sound, all of the premises must be true in the real world and not merely assumed to be true as in the case of the test for validity. - *Invalid Arguments* - *Valid Arguments* - use the word "ONLY" ![[Pasted image 20240125143851.png]] - *Inductive Arguments* - Not all invalid arguments are necessarily weak arguments; some are quite strong. - We must not automatically discard every invalid argument simply because it is not valid. - Some invalid arguments are inductive. - Inductive arguments provide a high degree of probability for their conclusions. - Inductive arguments consisting of premises that are all true in the real world are generally stronger than arguments that are valid but unsound. - Arguments with all true premises are more successful than are valid arguments that contain one or more false premises. - *Fallacious Arguments* - Whether an argument is fallacious or not has nothing to do with the actual truth or falsity of its premises. The problem is with the logic. - A logical fallacy is an error in reasoning that invalidate the logic. - Example: - P1: The Internet is in public space. - C: Those who use the Internet should not expect to retain any personal privacy. - Can a counterexample be produced? - YES – therefore the argument is invalid. - Is the argument inductive or fallacious? - Fallacious – because the conclusion does not likely follow from the premise even when the premise is assumed to be true. - ![[Pasted image 20240125144058.png]] - *Valid Arguments that are not Sound* - An argument can be valid (in virtue of its __logical form__), but still not succeed in accomplishing its task - *Sound and Unsound Arguments* - For an argument to be sound, it must satisfy two conditions – i.e., it must be: - valid (i.e., the assumed truth of the premises would guarantee the truth of the argument’s conclusion); - the (valid) argument’s premises must also be true in the actual world. ![[Pasted image 20240125144315.png]] *Invalid Arguments: Inductive vs Fallacious Reasoning* - An argument is invalid if you can give one counterexample to the argument. - We saw that a counterexample is - a possible case where the premises can be assumed to be true while, at the same time, the conclusion could be false (Nolt). - Invalid arguments will be either: - inductive; or - fallacious. *Inductive Arguments* - an argument is _inductive_ when - the conclusion would likely be true when the premises of the argument are assumed to be true. - Even though a counterexample to an inductive argument is possible, the argument’s conclusion would likely be true in the majority of cases where the premises are assumed true. *Fallacious Arguments* - An argument is *fallacious* when - The argument’s conclusion would not likely follow from its premises, even when all of the premises are assumed true. - Multiple counterexamples to a fallacious argument can be provided. ![[Pasted image 20240125145932.png]] ![[Pasted image 20240125145950.png]] **Seven-Step Strategy for Evaluating Arguments** 1. Convert the argument into standard form. 1. List the premises first, followed by the conclusion. 2. Test the argument for its reasoning strength to see whether it is valid or invalid. 1. Assume the premises to be true, and ask yourself whether the conclusion must also be true when those premises are assumed true. Is a counterexample to the argument possible? 3. Is the argument valid? 1. If yes, go to Step 4. 2. If no, go to Step 5. 4. Is the (valid) argument also sound? That is, are the premises true in the actual world? 1. If the argument is valid and if all of the premises are   true in the actual world, then the argument is also sound 2. If the argument is valid, but one or more premises   can be shown to be either false or not capable of being   verified in the actual world, then the argument is   unsound. 5. Is the (invalid) argument inductive or fallacious? (How likely will the conclusion be true when the premises are assumed true?) 1. If the conclusion would likely be true because the   premises are assumed true, the argument is inductive. 2. If the conclusion would not likely be true even when   the premises are assumed true, the argument is   fallacious. (Keep in mind that a fallacious argument can   be made up of individual claims that are themselves true   in the actual world.) 6. Determine whether the premises in your argument are either true or false. 7.  Make an overall assessment of the argument. That is, describe the argument's strength of reasoning in conjunction with the truth conditions of the argument's premises. 1. For example, is the argument inductive with all true premises? Is it inductive with some false premises? Is it fallacious with a mixture of true and false premises, and so forth? Remember that an inductive argument with premises that are all true is stronger than a valid argument with one or more false premises. **A Less Formal Strategy for Identifying Fallacious Arguments** - Fallacious != false statement - Fallacious == faulty reasoning **Some Common Informal Logical Fallacies** 1. Ad Hominem Argument - Ad hominem arguments attack the person rather than the substance of the person’s argument. 2. Slippery Slope Argument - The slippery slope fallacy has the form: - X could possibly be abused; therefore, we should not allow X. 3. Fallacy of Appeal to Authority - The Fallacy of Appeal to Popular Authority has the form: - X is an authority in field Y; X said Z; therefore, Z. NOTE – Y may have nothing to do with Z! 4. False Cause Fallacy - The false cause fallacy reasons from the fact that event X preceded event Y to the conclusion that event X is necessarily the cause of event Y. 5. Fallacy of Composition - The fallacy of composition confuses the characteristics that apply to the parts of a whole, or to the individual members of a group, with the characteristics of the whole of the group itself. 6. Fallacy of Division - The fallacy of division mistakenly infers that the same attributes or characteristics that apply to the whole or to the group must also apply to every part of the whole or to every member of the group. 7. Fallacy of Ambiguity/Equivocation - The fallacy of ambiguity occurs whenever one or more terms in an argument are used ambiguously or equivocally. - Ambiguous terms have more than one meaning. - Equivocal terms are used in more than one sense. 8. False Dichotomy/Either-Or/All-or-Nothing Fallacy - This fallacy typically presents us with two options that might initially seem to be mutually exclusive. - For example, one might assert: If you are not with us, you are against us, thus suggesting that no neutral ground is possible in a particular situation. - However, many claims, especially ones involving controversial political issues, appeal to a strict either/or rhetorical strategy in cases where additional options are indeed available. - For instance, some people claim that we must choose between privacy or security, while not showing why it is impossible to have both. 1. The Virtuality Fallacy (Moor, 2001) - PREMISE 1. X exists in cyberspace. - PREMISE 2. Cyberspace is virtual. - CONCLUSION. X (or the effect of X) is not real. [Quiz Review for Week 3](Quiz%20Review%20for%20Week%203.md)