PHI 1500: Major Issues in Philosophy

Transcription

1 PHI 1500: Major Issues in Philosophy Session 3 September 10 th, 2014 Methods: Reading Philosophy 1

2 Reading Philosophy As we saw from Russell s essay, it can be difficult to decode what an author is saying, especially when: The text reflects a historical style of wrikng we are not accustomed to reading The author is not very direct about the way his/her argument is presented Before we can determine what an author s argument is, we must know what an argument consists of.

3 What is an argument? Arguments are the currency of philosophy: they are what philosophers use to do business with each other An argument presents reasons (stated as premises) to accept a conclusion That conclusion is posed as a potenkal answer to a philosophical queskon As Pryor explains, - SomeKmes it will take skill to idenkfy the conclusion and the premises of an argument. You will oyen have to extract premises and conclusions from more complex and lengthy passages of prose. (5)

4 One text may contain mul3ple arguments. In addikon to presenkng a main argument, says Pryor, Philosophers oyen provide auxiliary arguments, arguments for important premises they appeal to in support of their main conclusion. For instance, the author's discussion may have the form: The conclusion I want you to accept is A. My argument for this conclusion is as follows: B and C are true, and if B and C are true, then A must also be true. It is generally accepted that B is true. However, it is controversial whether C is true. I think you ought to accept C for the following reasons Here the author's main argument is for the conclusion A, and in the process of arguing for A he advances an auxiliary argument in support of C. (1)

5 SchemaKzing arguments Recall our sample argument from Lecture 1: 1) Studying philosophy will improve your crikcal- thinking skills. 2) Good crikcal thinking skills will improve your score on the LSAT, GMAT, GRE, etc. 3) Therefore, you should study philosophy if you want to do well on the LSAT, etc. By convenkon, premises are listed above the line There must be at least one, but oyen, philosophers provide several premises Conclusions are listed below the line There may be one or more conclusions

6 An aside on causakon & correlakon 1) Studying philosophy will improve your crikcal- thinking skills. 2) Good crikcal thinking skills will improve your score on the LSAT etc. Each of these premises suggest that there is a causal relakonship between two factors (studying philosophy & improved crikcal- thinking, in 1; good crikcal- thinking & high standardized test scores, in 2) A causal rela0onship is one in which the occurrence or existence of one factor brings about another factor as a consequence. However, do we know for sure that these factors cause one another? They could merely be correlated.

7 Two factors are correlated when they tend to vary together They are directly correlated if they reliably change in the same direckon (both increasing or both decreasing), But indirectly correlated if they reliably change in opposite direckons (one increasing while the other decreases) CorrelaKon can result when changes in one factor funckons as the cause of changes in the other But it can also exist when there is no causal relakonship between the factors at all E.g., because there is an unconsidered third factor which causes both of the original factors to change Or as a complete coincidence

8 example of a Third Variable Problem : A city s criminal ackvity & its ice cream consumpkon are directly correlated Neither of these factors causes the other: both are increased when temperatures increase Temperature is the third variable: crime ice cream consumpkon Example of a coincidental correlakon: per capita cheese consumpkon & deaths by becoming tangled in bedsheets

9 Argument signposts premise- flags: because, since, given this argument, for examples: Your car needs a major overhaul, for the carburetor is shot. 1. The carburetor is shot. 2. (Therefore,) Your car needs a major overhaul. Because euthanasia is murder, it is always morally wrong. 1. Euthanasia is murder. 2. Euthanasia is always morally wrong Since aborkon is a hotly contested issue in this country, nobody should force his opinion about it on anyone else. 1. AborKon is a hotly contested issue in this country 2. Nobody should force their opinion about aborkon on anyone else.

10 Argument signposts conclusion- flags: thus, therefore, hence, it follows that, so, consequently examples: A woman's right to control what happens to her body always takes precedence over the rights of a fetus. Consequently, aborkon is always morally permissible. 1. A woman's right to control what happens to her body always takes precedence over the rights of a fetus. 2. AborKon is always morally permissible. Euthanasia involves choosing to die rather than to struggle on. Thus, euthanasia is a form of giving up, and it is therefore cowardly and despicable. 1. Euthanasia involves choosing to die rather than to struggle on. 2. Euthanasia is a form of giving up 3. Euthanasia is cowardly and despicable.

11 Hidden Premises An author won t always state every reason they can think of in support of their conclusion as a premise An argument oyen precedes on the assumpkon that certain unstated claims hold true We call these claims hidden premises E.g., there is a hidden premise in this argument: 1. If you drive your car with a faulty carburetor, it will eventually explode. 2. Therefore, if you drive your car with a faulty carburetor, you will eventually get hurt. It would be be<er read as: 1a. If you drive your car with a faulty carburetor, it will eventually explode. 1b. If your carburetor explodes, you will get hurt. 2. Therefore, if you drive your car with a faulty carburetor, you will eventually get hurt.

12 More signposts direc0on- changing signals: nevertheless, however, but These oyen signal that the author is about to say something that goes against something s/he has just presented e.g., a possibility s/he has brought up but wants to rule out, or a point made by another philosopher that s/he is going to argue against e.g.: The skepkc says that we can't tell whether we're seeing things as they really are, or whether we're brains in vats being force- fed false experiences, like the inhabitants of The Matrix. Y raised the following objeckon to the skepkc... Hence, Y concludes, we have no reason to think our situakon is as bad as the skepkc makes it out to be. This is an ahrackve response to the skepkc, but I don't think it can really work, for the following reason Y might respond to this problem in one of two ways. The first way is... However, this response fails because The second way Y might respond is... However, this response also fails because (Pryor 2)

13 Things aren t always straighjorward Not everything the author says will be a posikve conclusion or a premise in support of his conclusion. SomeKmes he'll be supporkng his view with a thought- experiment. SomeKmes he'll be arguing for a disknckon which his posi3ve view relies on. SomeKmes he'll be arguing that another philosopher's views or arguments ought to be rejected. SomeKmes he'll be defending a view against somebody else's objeckons. (2)

14 A thought- experiment is an imaginary scenario presented to help readers think through the consequences of a philosophical claim. Plato s Allegory of the Cave is a type of thought- experiment Another example: Frank Jackson s thought- experiment in which a neuroscienkst named Mary sees red for the first Kme. He uses this to argue that a view of the mind (called physicalism, as we will learn in November) makes a claim that he thinks we should reject. A philosopher presents a posi0ve view when they offer an answer to a queskon that they hope you to accept. They present a nega0ve view when they argue against an answer offered by another philosopher.

15 EvaluaKng Arguments Obviously, you're only in a posikon to evaluate an author's argument when you've done the work of figuring out what it is he's really saying, and how his arguments work. When you come to that point, you can start asking queskons like these: Do you agree with the author? If not, what do you think is wrong with his reasoning? Does he appeal to some premise which you think is false? (Why do you think it is false?) Is there some assumpkon which the author does not make explicit, but which you think is false? Does his argument equivocate or beg the ques3on? (Pryor 4)

16 Bad Reasoning equivoca0on*: a bad form of argument where one of the key terms can be understood in two ways, and the plausibility of the argument depends on reading the term differently in different premises. e.g., 1. Nature is governed by fixed and unchangeable laws. 2. Every law is the work of some legislator. 3. Therefore, there is some legislator responsible for the governing of Nature. begging the ques0on : making a circular argument, where the conclusion is assumed or presented in one of the premises offered in support of the conclusion. Certainly a bad form of argument. E.g., 1. The natural world shows order indicakve of intelligent design. 2. Therefore, a god designed the natural world.

17 A fallacy* is type of argument considered to be philosophically indefensible, either because it makes a logical error, or because it uses tackcs considered to be unacceptable in professional philosophy. Examples: Fallacies Appeal to authority: Claiming something is true because someone famous said so. Appeal to nature: Claiming something is good purely because it occurs naturally, or that something is bad because it is unnatural. Slippery slope: Assuming that one small claim will lead to a chain of (typically negakve) consequences.

18 What type of argument is being made? induc0ve* arguments use specific cases as evidence (premises) from which to draw general conclusions E.g., 1. All the swans we have seen are white. 2. Therefore, swans are generally white. One can never prove that a generalizakon is true. This is because it is always possible that in the future, a specific case will arise that contradicts the generalizakon. At best, induckve arguments can establish that a generalizakon is likely true, but not that it is defini3vely true Philosophers call this the problem of induc3on.

19 The Problem of InducKon Consider a slightly different induckve argument: 1. All the swans we have seen are white. 2. Therefore, all swans are white. Whoever made this argument did not know there are black swans! The existence of even a single non- white swan makes All swans are white false They should have presented the generalizakon in terms of likelihood ( Swans are likely to be white ), rather than as a fact.

20 What type of argument is being made? deduc0ve* arguments provide general principles as reasons to support a specific conclusion. They intend to establish a thesis conclusively, i.e., as a fact. Most philosophical arguments are deduckve. DeducKve arguments are commonly evaluated according to four standards: Validity Soundness Consistency Persuasiveness

21 Validity Valid arguments give us reason to believe their conclusions. An argument is valid if its premises entail* the conclusion. Premises entail a conclusion when it is impossible that the premises are true but the conclusion is false In other words, it is necessarily the case that the conclusion is true if the premises are true. The content of the premises and conclusion have no impact on whether or not the argument is valid. Validity is a property of the argument's form. It doesn't maher what the premises and the conclusion actually say. It just mahers whether the argument has the right form. So, in parkcular, a valid argument need not have true premises, nor need it have a true conclusion. (Pryor 7)

22 Validity Pryor says, To tell whether an argument is valid, figure out what the form of the argument is, and then try to think of some other argument of that same form and having true premises but a false conclusion. If you succeed, then every argument of that form must be invalid. A valid form of argument can never lead you from true premises to a false conclusion. (8) So to tell if an argument is valid, rewrite it in its logical form. To do so, we replace statements within the premises and conclusions with le<ers.

23 E.g.: Validity 1. Socrates was either a philosopher or a historian. 2. Socrates wasn't a historian. 3. So Socrates was a philosopher. Let P stand for Socrates was a philosopher, H for Socrates was a historian. Then: 1. P or H. 2. Not H. 3. Therefore P. This is a valid argument form called modus ponens. Any argument with this form will be valid.

24 Another example: Validity 1. If someone is enrolled in PHI 1500, their name is on the roster. 2. Kanye West s name is not on the roster. 3. Therefore, Kanye is not enrolled in PHI Let E stand for someone is enrolled in PHI 1500, N for their name is on the roster. Then: 1. If E, then N. 2. Not N. 3. Therefore not E. This valid argument form is called modus tollens. Statements of the form If P, then Q (like 1) are called condi0onals. (We won t worry about these for now.)

25 Some invalid argument forms Invalid arguments give us no reason to believe their conclusions. But be careful: The fact that an argument is invalid doesn't mean that the argument's conclusion is false. The conclusion might be true. It's just that the invalid argument doesn't give us any good reason to believe that the conclusion is true. (Pryor 9)

26 Soundness An argument is sound just in case it's valid and all its premises are true. The argument: 1. If the moon is made of green cheese, then cows jump over it. 2. The moon is made of green cheese. 3. Therefore, cows jump over the moon. is an example of a valid argument which is not sound. Sound arguments always have true conclusions. This means that if you read Philosopher X's argument and you disagree with his conclusion, then you're commihed to the claim that his argument is unsound. Either X's conclusion does not actually follow from his premises there is a problem with his reasoning or logic or at least one of X's premises is false. (Pryor 10)

27 Soundness: Exercises

28 An argument is persuasive if it is a valid argument with plausible, or obviously true, or antecedently accepted premises. (Pryor 12) An argument is inconsistent if its premises contradict each other. A contradic0on is a proposikon that's inconsistent with itself, like P and not- P.

29 Reading Strategies You should expect to read a philosophy arkcle more than once. First, skim the ar3cle to idenkfy what the author's main conclusion is. When you do figure out what the author's main conclusion is, try to restate it in your own words. When you've figured out what the main conclusion of an arkcle is, and what the overall structure of the arkcle is, go back and read the arkcle carefully. Pay ahenkon to how the various parts fit together.

30 Most importantly, figure out what the author's central argument(s) are. What reasons does he offer in support of his conclusions? Where in the arkcle does he put these reasons forward? Also keep an eye out for the following: NoKce where the author says explicitly what he means by a certain term. NoKce what disknckons the author introduces or argues for. Take special nokce of any unargued assumpkons you think the author is relying on. Consider various interpretakons of what he says. Are there any important ambiguikes that his argument fails to take account of? (Pryor 3)