Walter Sinnott-Armstrong Phil 3 (10/1/02) THE LANGUAGE OF ARGUMENT 1 - HOW TO IDENTIFY AN ARGUMENT 1.1 - Argument Markers (32-3) 1.11 - Conclusion Markers: 1.111 - words: therefore, so, thus, hence, then, etc. 1.112 - phrases: which goes to show that..., etc. 1.113 - performatives: I conclude that ... (33, 46, 6) 1.12 - Reason Markers: 1.121 - words: since, because, for, etc. 1.122 - phrases: which follows from the fact that..., etc. 1.123 - performatives: I base my argument on the premise that ... (33, 46, 6) 1.2 - If-then or Conditionals (33-4) 1.3 - Warning: Arguments cannot be identified mechanically by their words alone. You must consider what the speaker intends the words to mean and do. Test: A word indicates an argument if you can replace it with other argument markers without changing the force of the sentence. (32) 2 - STANDARD FORM: Three simple steps (35) 2.1 - list reasons Premise 2.2 - draw a line Premise ________________ 2.3 - then write a dot pyramid and the conclusion Conclusion 3 - SOME STANDARDS FOR EVALUATING ARGUMENTS 3.1 - Validity 3.11 - Definitions 3.111 - An argument is valid if and only if it is not possible that both 3.1111 - all of its premises are true, 3.1112 - and its conclusion is false. (36) 3.112 - In other words, an argument is valid if and only if, when all of its premises are true, its conclusion must also be true. 3.113 - In still other words, an argument is valid if and only if, when its conclusion is false, at least one premise must also be false. 3.114 - Finally, an argument is valid if and only if its premises logically imply its conclusion (but NOT when they only conversationally imply it). 3.12 - Kinds of Valid Arguments: True Conclusion False Conclusion True Premises Some Valid, Some Not ALL INVALID A False Premise Some Valid, Some Not Some Valid, Some Not So there are seven kinds of examples: Assume: All Ford cars have four tires. Henry’s only car is a four-door Ford. Lee’s only car is a four-door Chrysler. Mary’s only car is a two-door Chrysler. 3.121 - Arguments with all true premises and a true conclusion: Valid: All Ford cars have four tires. Invalid: All Ford cars have four tires. Henry’s car is a Ford. Henry’s car has four tires. Henry’s car has four tires. Henry’s car is a Ford. 2 (Why? Henry could buy Lee’s car, which has four tires but is not a Ford.) 3.122 - Arguments with all true premises and a false conclusion: Valid: IMPOSSIBLE Invalid: All Ford cars have four tires. Lee’s car has four tires. Lee’s car is a Ford. 3.123 - Arguments with at least one false premise and a true conclusion: Valid: All Fords have four doors. Invalid: All Fords have four doors. Henry’s car is a Ford. Henry’s car has four doors. Henry’s car has four doors. Henry’s car is a Ford. (Why is the left argument valid? Although the first premise actually is false, it is possible for it to be true; and if it were true (if all Fords had four doors), and if the second premise were also true, as it is, then under those conditions it would have to be the case that Henry’s car has four doors. No scenario is possible where all of the premises are true and the conclusion is false.) 3.124 - Arguments with at least one false premise and a false conclusion: Valid: All Fords have four doors. Invalid: All Fords have four doors. Mary’s car is a Ford. Mary’s car has four doors. Mary’s car has four doors. Mary’s car is a Ford. 3.125 - The reason why these seven variations are possible is that validity depends not on which sentences are actually true or false but instead on what is possible and on relations among sentences. 3.13 - Tricky Cases (38-9) – don’t worry about these! 3.2 - Soundness 3.21 - Definition: An argument is sound if and only if BOTH it is valid AND all of its premises are true. (38) 3.22 - Kinds of Sound Arguments: Premises Conclusion Valid Invalid True True SOUND (3.121L) Unsound (3.121R) True False Impossible Unsound (3.122R) False True Unsound( 3.123L) Unsound (3.123R) False False Unsound (3.124L) Unsound (3.124R) 3.23 - So there are two ways to be unsound: An argument is unsound if 3.231 - either it is invalid (the right column of 3.22) 3.232 - or it has a false premise (the bottom two rows of 3.22). 3.24 - The Value of Soundness 3.241 - All sound arguments have true conclusions. (38) 3.242 - Some sound arguments are not good arguments. (41, 406; for example, circular arguments like: God exists, so God exists). 4 - THE REGRESS OF SCEPTICISM (41): Every argument must either 4.1 - start with premises for which no argument is or can be given, 4.2 - or go on infinitely (its premises are supported by arguments with premises 3 that are supported by arguments with premises that are ...), 4.3 - or circle back on itself (parts of the argument reappear as premises in the arguments for themselves). 4.4 - The Problem: Each of these options seems to make the argument no good. 5 - PRACTICAL SOLUTIONS: some ways to protect premises against attack 5.1 - Assuring = indicating that reasons can be given without giving any reasons (42-3) 5.11 - Kinds of assurances or assuring terms and phrases 5.111 - Authoritative: studies have shown that, doctors agree that, etc. 5.112 - Reflexive: I am sure that, I can assure you that, etc. 5.113 - Abusive: only a fool would deny that, it is common sense that, etc. 5.12 - Assurances are needed when 5.121 - someone might challenge what we say, 5.122 - but our audience does and should trust the cited authority, 5.123 - and it would be too much trouble to spell out our reasons. 5.13 - Assurances are not appropriate when 5.131 - nobody would question this claim anyway, 5.132 - or our audience does not or should not trust the cited authority, 5.133 - or we could state the reasons without too much trouble. 5.14 - The trick of abusive assurances (e.g. “Nobdy but a fool would doubt that ...”) 5.2 - Guarding = weakening a claim, so it is harder to refute (43-4) 5.21 - Kinds of guards or guarding terms 5.211 - Extent: all most some 5.212 - Probability: certain likely possible 5.213 - Cognitive state: know believe tend to believe it seems to me 5.22 - The Middle Way: premises should be weak enough to be defensible, but also strong enough to support the conclusion. 5.221 - Guarding is needed when an unguarded premise would be denied. 5.222 - Guarding is appropriate when the guarded premise still provides enough support for the conclusion. 5.223 - Guarding is not appropriate (= hedging) when the guarded premise does not provide enough support for the conclusion. 5.23 - Tricks (44) 5.231 - Insinuation: Angela Davis, “Something is wrong here.” (Of course!) 5.232 - The Disappearing Hedge: Gore could have known, so we can’t trust him. 5.3 - Discounting = citing a possible criticism in order to reject or counter it 5.31 - Kinds of discounters or discounting terms (44-6) 5.311 - overriders = claim that opposing reasons are less important 5.312 - deniers = deny opposing reasons that are conversationally implied 5.313 - Example: “import quotas are dangerous, but our farmers need them, and they will only be temporary” (overrider, then denier) 5.32 - Discounting is needed when a criticism is likely, and the issue will be confused if your opponent raises that criticism in a misleading way. 5.33 - The trick of discounting straw men (46; compare 78-79, 94) 4 5.4 - Test: Can you replace this Guarding/Assuring/Discounting term with another Guarding/Assuring/Discounting term without changing meaning? (32) A DISAPPEARING HEDGE from Douglas Lackey, “Missiles and Morals” in Philosophy and Public Affairs (1982) The case for nuclear disarmament in the multilateral situation is much stronger than the case for nuclear disarmament in the bilateral situation if one considers the import of Richard’s theorem, proved in the 1930s, that if every pair of a triplet of nations is stable, the triplet itself may still be unstable. For example, even if the relations between the United States and the Soviet Union, the Soviet Union and China, and China and the United States are relatively stable, it is possible that the ensemble of these three nations is unstable, producing an arms race, and perhaps even a war. On the other hand, relative stability can be restored by any nation in the triplet that unilaterally withdraws from the nuclear club. Thus, unilateral disarmament reduces the chance of war among those nations that do not choose to disarm, a result that recommends itself both prudentially and morally. In sum, if a nation is better off with Nuclear Disarmament in the bilateral case, it is even better off with nuclear disarmament in the multilateral case.