Logic In LD

7/30/2019 Logic In LD

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Logic In LDby Jason Baldwin

Part I: Elements of Theory ! 1I. Preliminary Notions! 1II. Three Valid Forms! 2III. Practice! 7

Part II: Casing Applications ! 9I. Burdens! 10II. Research! 12III. Contention Mapping! 15IV. Value Premise(s)! 22V. Contention Development! 26

Part III: Cross-Examination and Rebuttals ! 31I. Basic Principles! 31II. Cross-Examination! 32III. Rebuttals! 36IV. Final Issue Selection! 39

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Part I: Elements of Theory

The purpose of this article is to introduce LD debaters to a few basic elements of formallogic; later articles will explore some applications of logic to the practice of debate.

Some people say that high school debate should be conducted and judged on the basisof logic alone-sola ratione, so to speak. Anyone acquainted with logic as a deductivescience will have a hard time figuring out what these people mean. If they mean simplythat debaters should avoid being illogical, well and good-but then who has eversuggested that debaters should be illogical? If they mean that the resources of logicshould be sufficient to settle the truth of any debate resolution, they are betraying abasic confusion about the power of logic. Trying to generate substantive truths usingonly logic would be like trying to generate money using only arithmetic. Hopefully thereaders of this article will come to understand why.

I. Preliminary NotionsDespite its limitations, logic is an indispensable tool in debate. Logic is the science ofarguments. An argument is a set of sentences, one member of which is the conclusionand the others of which are premises offered in support of the conclusion. An inductiveargument is one in which the premises are intended to make the conclusion likely orprobable. For example,

(1) Most Alabamians own guns.(premise) (2) Pat is an Alabamian.(premise) (3) Therefore, Pat owns a gun.(conclusion)

If both premises of this argument are true, they provide evidence supporting theconclusion, but they do not render the conclusion certain. Perhaps Pat is a member ofthe tiny Alabama chapter of Handgun Control and believes it is immoral to own guns.

A deductive argument, by contrast, is one in which the premises are intended to makethe conclusion certain. For example,

(4) No wombats are mammals.(premise) (5) J.S. Mill is a wombat.(premise) (6) So J.S. Mill is not a mammal.(conclusion)

If both premises of this argument are true, they make the conclusion not merelyprobable, but absolutely certain.

Obviously anyone who wants to argue for a given conclusion will prefer a deductive toan inductive argument when the former is available. Most constructive arguments in LDcan be represented as deductive, and deductive arguments are the only sort of

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arguments which we can assess with a formal precision akin to that of mathematics.Therefore, we will focus exclusively on deductive arguments.

Astute readers will have noticed that the sample deductive argument above-about J.S.Mill-contains a glaring problem: Both of its premises and its conclusion are false. And

yet it is as good logically as an argument can be. What gives? The argument is valid.That means that if the premises are true, the conclusion must be true. To determine thatthe argument is valid, we do not have to know whether the premises really are true ornot. We can simply recognize that if the premises were true, the conclusion would alsohave to be true. So if no wombats are mammals and if J.S. Mill is a wombat, then J.S.Mill is not a mammal. But the argument is not sound. A sound argument is one which isvalid and in which all the premises are true. This means that all sound arguments arevalid (by definition), but not all valid arguments are sound (because some validarguments have one or more false premises). Given the definition of validity, you cansee that a sound argument must also have a true conclusion.

Please note that only an argument can be valid or invalid, sound or unsound; sentencesor propositions do not possess these properties. Likewise, only sentences orpropositions can be true or false; arguments cannot be true or false.

Obviously someone making an argument wants a sound argument, not merely a validargument. But logic can deliver only validity. That is, an argument may be as logical asyou please but still have a false conclusion. Logic tells us what propositions(conclusions) follow from the propositions (premises) we already believe, but it cannottell us which propositions to accept as premises in the first place. Garbage in, garbageout, as they say. This is not just your author's opinion, or the majority view amongprofessional logicians; nor is it a prediction or a generalization. It is the sober and

indisputable truth about logic.

Already, you should begin to see the problem with the view that any interesting debatecould be settled on the basis of logic alone. The only way a debate might be settled bylogic alone is if both sides agreed to the same premises and the dispute were simplyover the validity of the inference from those premises to competing conclusions. Butdebates are almost never like that-the debaters argue to different conclusions fromdifferent sets of premises. Often both sides present valid arguments, and the realquestion is, whose premises should be believed? For better or worse, logic by itselfcannot answer this question.

II. Three Valid FormsWe said above that an argument has the property of validity when its conclusion mustbe true if its premises are true. But how can you ensure that your own arguments havethis valuable property? Arguments are valid or invalid on the basis of their form, not onthe basis of their content. In other words, it doesn't matter what the sentences in theargument are about or whether they are true or false. As long as the sentences aredeclarative and are properly arranged (more on this below), the argument they compose

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will be valid. The bad news is that there are literally an infinite number of valid argumentforms. The good news is that we can represent most of the deductive arguments usedin LD with only three simple forms.

To focus your attention on these forms, it will help to introduce a few symbols. Let us

use the italicized letters p, q, r, and s to stand for declarative sentences. We will use thetilde (~) written before a sentence to signify the negation of that sentence. So if I assert~p, then I am claiming that the declarative sentence p is false. Finally, let us symbolizeconditional (if-then) sentences using an arrow () with the appropriate componentsentences written at either end of the arrow. Conditional sentences are complexsentences-that is, they are composed of two simpler sentences. The first of thesecomponent sentences comes after the "if" and is called the antecedent. The secondcomponent sentence comes after the "then" and is called the consequent. Consider, forexample, this conditional sentence: If it rains, then I will skip the game. The antecedentof this sentence is "it rains," and the consequent is "I will skip the game." If p stands for"it rains" and q stands for "I will skip the game," then we can represent the conditional

sentence as: pq.

Now we can introduce the three valid argument forms we need. The first is calledmodus ponens (MP). A modus ponens argument is of the form:

pq (premise) p (premise) So q (conclusion)

Here is an example of a valid MP argument:

(7) If capital punishment deters crime, then capital punishment is moral.(premise) (8) Capital punishment deters crime.(premise) (9) Therefore, capital punishment is moral.(conclusion)

Even if you believe that (7) or (8) is in fact false, you can see that the argument is valid:if (7) and (8) are true, then (9) must also be true.

It may or may not be obvious to you that the order of the premises makes no differenceto the validity of the argument. We could have switched (7) and (8), and (9) would justas surely follow. However, the order in which you present the premises of an argumentcan be very important to your audience's grasp and acceptance of the argument, and

we will return to this subject briefly in a future article.

The second crucial argument form is modus tollens (MT), which is:

pq (premise) ~q (premise) So ~p (conclusion)

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In the abstract, modus tollens is less obviously valid to most people than is modusponens. But in fact, every MT argument is valid, and we use this pattern of reasoning allthe time. For example,

(10) If all human life were sacred, then it would be wrong to defend the innocent

with lethal force.(premise) (11) But it's not wrong to defend the innocent with lethal force.(premise) (12) So not all human life is sacred.(conclusion)

Again, the order of the premises in an MT argument does not matter. So long as onepremise is of the form pq and the other premise is of the form ~q, the conclusion ~pnecessarily follows.

The third and final valid argument form we need is called hypothetical syllogism (HS):

pq (premise)

q

r (premise) So pr (conclusion)

Unlike modus ponens and modus tollens, every sentence in a hypothetical syllogism isa complex conditional sentence-there are no simple p's or q's as premises orconclusion. Here is an example:

(13) If pornography demeans women, then pornography communicates ideas.(premise)

(14) If pornography communicates ideas, then pornography is a form of speech.(premise)

(15) So if pornography demeans women, then pornography is a form of speech.(conclusion)

You should memorize the three argument forms we have learned so far. Your ability toapply these forms to more complex debate arguments will depend on your ability torecognize the simpler forms instantly.

Before learning how to apply MP, MT, and HS to more complex arguments, we shouldnote two common fallacies or invalid forms which resemble the valid forms above. Whatmakes a form of reasoning fallacious rather than valid? Simply that its premises even iftrue do not guarantee the truth of its conclusion. One common fallacy is denying the

antecedent:

pq (premise) ~p (premise) So ~q (conclusion)

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The best way to show that a given form of reasoning is fallacious is to produce acounter-example to it-an example of the form in question which has obviously truepremises but an obviously false conclusion. For instance:

(16) If pine trees are pink, then pine trees are colored. (premise)

(17) Pine trees are not pink.(premise) (18) So pine trees are not colored.(conclusion)

Both premises are true, but the conclusion is false-pine trees are green, and thereforecolored. The moral: Don't deny the antecedent!

The second fallacy you should take special care to avoid is called affirming theconsequent, and it looks like this:

pq (premise) q (premise)

So p (conclusion)

We can use the same first premise about pine trees to demonstrate the invalidity of thisform:

(19) If pine trees are pink, then pine trees are colored.(premise) (20) Pine trees are colored.(premise) (21) So pine trees are pink.(conclusion)

Here we have true premises but a false conclusion, proving that the argument isfallacious. Don't affirm the consequent!

With these warnings out of the way, we are ready to combine the simple argumentforms into more complex patterns. First, instances of HS can be stacked one uponanother, and validity will be preserved. If we have as premises

pq qr rs

then we can validly conclude

So p

s.

Think about it. We can apply HS to the first two premises to conclude p--r, and we canapply HS a second time to this conclusion and the third premise to get p--s. In fact,logically speaking, it doesn't matter how many conditionals we stack up. We can applyHS as many times as necessary to collapse a stack of properly related conditionals intoa single conditional conclusion. (To be properly related, the conditionals must be such

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that the consequent of one conditional is the antecedent of another, whose consequentis the antecedent of another, and so forth.)

Further, we can combine instances of MP or MT with instances of HS. So, e.g., from thepremises

~r pq qr

we can validly conclude

~p.

How does this work? Again, we are simply combining premises two-at-a-time using MP,MT, or HS to reach subconclusions, which we then combine with remaining premises

using further applications of MP, MT, or HS. In this case, we applied MT to the first andthird premises, which yielded ~q as a subconclusion. Then we combined thissubconclusion with the second premise in another application of MT to reach the finalconclusion ~p.

Instead of applying MT twice, we could just as easily (and validly!) have applied HS tothe second and third premises to yield pr and then applied MT once to thissubconclusion and the first premise to yield the same final conclusion ~p.

From what we have said so far, you may already be able to see that we can combinethe two forms of complex arguments to produce valid arguments of any length. If we let

p* stand for a sentence different from p, we can use the premises

p pq qr rs sp* p*q* q*r* r*s*

to conclude

s*.

We do this by applying MP repeatedly, beginning with the first two premises andcontinuing down the chain, or (if you prefer) by applying HS repeatedly to the secondthrough eighth premises and then applying MP once to the first premise (p) and final

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subconclusion (ps*).

III. PracticeAnd that's it. If you have followed me this far and have learned the three argument

patterns explained above, you know enough formal logic to be an excellent debater. Ofcourse, knowing this (or any) amount of formal logic does not guarantee that you'll bean excellent debater. You need to know how to apply your theoretical understanding ofargument forms to real arguments. Later articles will discuss the application of thelogical theory outlined here to LD cases and rebuttals. For now, you need to begin torecognize valid (and invalid) logical forms when you encounter them in spoken andwritten arguments. Arguments, as you know, do not typically present themselves asnumbered lists of premises and conclusions. Instead, they come cloaked in prose, andyou must learn to probe for the logical skeleton beneath the flesh of prose.

Here is an example of a typical written argument, the kind you might encounter (albeit at

greater length) in an LD case:

American colleges ought not to practice race-based affirmative action becausedoing so will lead to massive human suffering. Affirmative action will makecolleges more appealing to students from other countries because it will increasetheir chances for admission. When more foreign students graduate fromAmerican colleges, more foreigners will stay in the U.S. and compete for high-paying jobs. This will put Americans out of work, which will destroy our economy.The collapse of our economy would destabilize the world politically, triggering anuclear war. And we must do everything we can to prevent a nuclear war.

You'll notice that there is not a single if-then sentence in this paragraph. But we caneasily translate the paragraph into a form which more clearly displays its validity:

(22) Affirmative action will increase the chances of foreign students for admissionto U.S. colleges. (premise)

(23) If affirmative action will increase the chances of foreign student foradmission to U.S. colleges, then affirmative action will make U.S. colleges moreappealing to foreign students.(premise)

(24) If affirmative action will make U.S. colleges more appealing to foreignstudents, then affirmative action will cause more foreign students to enroll in andgraduate from U.S. colleges.(premise)

(25) If affirmative action will cause more foreign students to enroll in andgraduate from U.S. colleges, then affirmative action will cause foreign students tostay in the U.S. after graduation and compete with U.S. citizens for jobs.(premise)

(26) If affirmative action will cause more foreign students will stay in the U.S.after graduation and compete with U.S. citizens for jobs, then affirmative actionwill cause U.S. citizens to lose their jobs.(premise)

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(27) If affirmative action will cause U.S. citizens to lose their jobs, then affirmativeaction will destroy the U.S. economy.(premise)

(28) If affirmative action will destroy the U.S. economy, then affirmative action willdestabilize the world politically.(premise)

(29) If affirmative action will destabilize the world politically, then affirmative

action will cause nuclear war.(premise) (30) If affirmative action will cause nuclear war, then affirmative action will causemassive human suffering.(premise)

(31) If affirmative action will cause massive human suffering, then Americancolleges ought not to practice affirmative action.

(32) So American colleges ought not to practice affirmative action.(conclusion)

If you symbolize this argument using p's and q's, you'll see that is it almost identical inform to the long argument which concluded with s* above.

If you compare my premise-conclusion restatement of the argument with the original

paragraph version, you'll see that the conclusion and the last premise of the argumentare both expressed by the first sentence of the paragraph version. The next-to-lastpremise, that nuclear war causes massive human suffering, is never stated outright inthe paragraph, but we added it to our formalization in order to ensure the argument'svalidity. Sometimes there are good rhetorical reasons to leave premises unstated, butfor the purposes of mastering the logic of arguments, you should work to make everyassumption explicit. Much of the best philosophy consists in identifying and challengingpremises which are usually taken for granted.

So how good is the affirmative action argument? Well, if we accept the formalization assuggested, the argument is logically impeccable. It is valid-the conclusion follows

necessarily from the premises-and that is all we can demand logically from anyargument. But logical or not, the argument stinks. Although the argument's moral (ornormative) premise (31) is plausible, the argument also relies on a string of eightempirical (or descriptive) premises (22-29), all of which must be true for the argument toreach its announced conclusion. These empirical premises are not at all plausible.Perhaps there is good evidence supporting a few of them, but most look wildlyexaggerated, and taken together, they are surely indefensible. Because of HS, premises(22)-(29) together entail that if affirmative action increases college admission chancesfor foreign students, then it will cause nuclear war. No one who understood all the wordsin that conditional could believe it, and no smart debater would want to have to defendsuch a far-fetched premise in order to attack affirmative action. But for now, the point is

that despite its obvious weaknesses, the argument is logically valid, and anysubstantive debate about the argument will be decided not by logic alone, but rather bynon-logical empirical or normative disputes about the truth of the argument's premises.

You can find arguments to analyze anywhere people are making arguments. Try lookingat the editorial page or watching the talking heads on the news channels. Rarely will youfind an argument presented as explicit instances of MP, MT, or HS. Your challenge is totranslate the natural language of the arguer into the somewhat stilted if-then premises

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you have learned to check for validity. You will almost always have to add one or morepremises which are only implicit in the argument's original presentation.

If you hear what you know is an argument but have no idea where to begin in mappingit, first find the conclusion. If the conclusion is best represented as a conditional, you

know all the premises will be conditionals. If the conclusion is not a conditional, then youshould expect at least one simple premise-represented by a non-conditional such as por ~q-to make up part of an MP or MT. Work backwards from the conclusion through thechain of premises until you arrive at the starting point.

Finally, keep in mind that the three argument forms presented above, while adequate torepresent the vast majority of, and maybe all, LD case arguments, are only a smallfraction of the standard argument forms available in modern formal logic. Many real-lifearguments, and some LD arguments, will have to be shoe-horned quite awkwardly to fitinto these patterns, and some arguments will not fit at all. Fortunately, there are logicaltools available to represent almost any deductive argument. Unfortunately, the Rostrum

is not the place (and I am not the author) to acquaint you with that full set of tools. Youmay know other valid argument forms which allow you to represent this or thatargument more gracefully than you could using only MP, MT, and HS. You should use allthe logical tools at your disposal when you approach an argument. If you find the notionof a logical calculus scintillating, you should take a formal logic course in college, oreven pick up a logic textbook and teach yourself.1 The sequels to this article willpresuppose only a familiarity with MP, MT, and HS, but everything they say will apply toall valid arguments, regardless of form or complexity.

Part II: Casing Applications

This article illustrates some applications of formal logic to the development of LD cases.It presupposes familiarity with the elements of formal logic introduced last month. Byway of review, an argument is a set of sentences some of which (the premises) areoffered in support of another of which (the conclusion). A valid argument is an argumentof a form such that if its premises are true, its conclusion must be true, and a soundargument is a valid argument with true premises (and hence a true conclusion). Weintroduced three valid argument forms which can be combined with each other in avariety of ways: (1) MP-Modus Ponen (pq, p, so q); (2) MT-Modus Tollens (pq, ~q,so ~p); and (3) HS-Hypothetical Syllogism (pq, qr, so pr). If any of the foregoing is

unfamiliar, you should review the earlier article before proceeding with this one.

I will discuss the applications of logic to LD casing under five headings: burdens,research, contention mapping, value structure, and contention development. Myunderlying thesis is that an LD case is best conceived as the presentation of one ormore deductively valid arguments. Among my more interesting conclusions is thatdebaters should drastically revise the traditional value premise (or core value) and

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criterion model of argument.

I. BurdensThere is much confusion about the burdens of LD speakers. What is each side's basic

responsibility? What, if anything, must each side prove? This section is the mosttheoretical in this article. If you don't care about debate theory and simply want to knowmy answer to the above questions, you can skip to the last paragraph of this sectionand keep reading from there.

Some LD students and judges are eager to embrace a picture of burdens borrowedfrom policy debate. In policy debate, there is a standing burden of proof on theaffirmative and a corresponding presumption for the negative. That means that in thecase of a tie (including the sort of tie that would result if neither side made anyspeeches), the judge should vote for the negative. The affirmative must prove the policyresolution is true, and the negative must destroy whatever arguments the affirmative

makes. However, the negative does not have to prove that the resolution is false.

You might wonder how a policy negative could destroy the affirmative's argumentswithout proving the resolution false in the process. The answer is, in part, that you candestroy an argument without claiming anything about the truth or falsehood of theargument's conclusion. A good argument is a sound argument. And a sound argument,you will recall, is an argument which is deductively valid and which has only truepremises. But an argument which is invalid or which has false premises may still have atrue conclusion. Nonetheless, it's a bad argument because we can't know theconclusion is true based on the premises offered. So if we represent the policyresolution as p, the negative team may undermine the affirmative's argument that p

without proving (or even attempting to prove) that ~p. There are further reasons why apolicy negative can refute the affirmative's argument without actually disproving theresolution, but those reason are related to conventions of policy debate and do notconcern us here.

What does concern us is that LD does not have prescribed burdens and presumptioncomparable to those in policy debate. The NFL's official LD ballot instructs judges that"There are no prescribed burdens in L-D as there are in policy debate; no 'burden ofproof' and no 'presumption.'" This means that if there were an argumentative tie in anLD round, the negative would not win by default. No one would win by default.

More importantly, the lack of prescribed burdens means that it is not sufficient in LD, asit is in policy, for the negative merely to attack the affirmative's arguments. The negativemust offer constructive arguments of its own, arguments which conclude that theresolution is false. For suppose the affirmative offers two arguments, each of whichconcludes that p (the resolution) is true. And suppose the negative follows the policystrategy of merely attacking those two arguments-showing that they are insufficient toprove that p. But the negative (as we are supposing) offers no independent argumentsto prove that ~p, i.e., that the resolution is false. Then the negative has effectively

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destroyed the affirmative's reasons for believing the resolution without offering anyreasons to disbelieve it. And since there is no presumption in LD, if there are no reasonsto believe the resolution and no reasons to disbelieve it, there is no reason for the judgeto vote one way or the other.

It's as if the debate begins with a tie (since there is no presumption) and the affirmativecase attempts to break the tie by proving the resolution true. If the negative merelydisarms the affirmative's attempted tie-breaker, we are back to a tie again. To win, thenegative must do more than simply disarm the affirmative's tie-breaker. The negativemust attempt to break the tie in the other direction, by proving the resolution false.

So we might think of LD affirmatives as having a burden to prove the resolution true, butonly in a sense of "having a burden" such that LD negatives equally have a burden toprove the resolution false. This means that there are no burden strategies which areopen to the negative but not to the affirmative just in virtue of the rules of LD. In otherwords, the standing burdens of each side are symmetrical. Therefore, refuting

affirmative arguments is not sufficient to negate an LD resolution.

However, there may still be a range of legitimate negative strategies on this or thatparticular LD resolution. We can say generally that the negative must prove theresolution false, but there are different ways different kinds of propositions can befalsified.

Consider the resolution that "The possession of nuclear weapons is immoral." It's clearenough what the affirmative is responsible to prove. But what must the negative prove?That the possession of nuclear weapons is morally good? If the negative proved that,the negative would certainly be proving the resolution false. But there are other ways

the resolution could be false as well. The negative could prove, less ambitiously, that thepossession of nuclear weapons is neither morally good nor bad; it is morally neutral.This conclusion logically implies the falsehood of the resolution. But the resolution isalso false (it seems) if morality is a myth-if nothing is morally good, bad, or even neutral.For if no actions have moral properties, it is obviously false that any particular action(such as the possession of nuclear weapons) has the property of being immoral. Soeven on this simple resolution, there are several routes the negative could take to fulfillits burden of proving the resolution false.

Now consider a more complicated resolution, that "As a general principle, individualshave an obligation to value the common good above their own interests." People often

refer to resolutions of this sort as "comparative," and it is comparative resolutions thatgenerate the most controversy about negative burdens. Let us again use p to representthe resolution. What counts as ~p? Many people believe that the negative's burden onsuch a comparative resolution is to prove the converse of the resolution-in this case, toprove that individuals ought to value their own interests above the common good. Andno doubt, if individuals ought to prefer their own interests to the common good, then it'sfalse that individuals ought to prefer the common good to their own interests. So provingthe converse is one way for the negative to satisfy its burden to show that ~p.

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But there are other ways to show that ~p. Suppose the negative could prove that whatan individual should prefer varies from situation to situation and from individual toindividual. Then it would be false that as a general principle individuals ought to preferthe common good to their own interests. There is nothing incoherent about this position,

and it has been defended by many philosophers. Or suppose the negative could provethat there is a general principle, but that the principle is that individuals ought to valuetheir own interests and the common good equally. I think this principle would be difficultto defend, but if it's true, then the resolution is false, and the negative has yet anotherway to satisfy its burden.

The position on negative burdens which I am now defending is a reversal of an earlierposition. I used to believe that the negative had to defend the converse of acomparative resolution. I still believe that defending the converse often makes for thestrongest negative positions, but I no longer believe that the rules of LD or the ethics ofargument require the negative to defend the converse.

My present position is likely to please no one. Some people will think it allows too manynegative options, including "balance negatives," "situational negatives," or "criticalarguments" (I put these terms in quotation marks because I am often unsure whatpeople mean by them). Other people will think my view is too restrictive by requiring thenegative to defend a proposition rather than simply attacking the affirmative'sarguments.

Of course, I think my view is just right. More specifically, I think it best accounts for tworelevant facts: The first fact is that there is no prescribed burden of proof and nopresumption in LD. This fact requires that the negative (if it wants to secure a win rather

than just a tie) must prove a proposition, namely, the proposition ~p which is the denialof the resolution p. The second fact is that depending on what p says, there may bemany ways to prove ~p-including more ways than simply proving the converse of acomparative resolution. I am not equally enthusiastic about all of these ways, but I thinkanyone who understands the logical significance of denial must at least be open tothem.

So in sum we can say that the affirmative's basic burden is to prove that the resolutionis true and the negative's basic burden is to prove that the resolution is false. Dependingon the resolution, there may be many ways to prove the resolution false. But if we use pto represent the resolution and ~p to represent "it is false that p," then the affirmative

case should make arguments the conclusion of which is p, and the negative caseshould make arguments the conclusion of which is ~p.

II. ResearchThere are at least two sorts of research relevant to constructing a debate case. The firstsort is general research conducted for the purpose of finding arguments to prove aresolution true or false. The second sort is focused research to support this or that

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premise of an argument which you have already constructed. Here I am concerned onlywith research of the first sort.

It is best to begin research on every topic by reading several general survey chaptersand articles before hunting for specific arguments. These surveys will often be entries in

reference books, literature reviews in journals, chapters in textbooks, or introductions inmonographs (books by a single author) and edited anthologies. In addition tosuggesting further sources to pursue, this reading will acquaint you with the history ofthe controversy, the main areas of dispute, and the relevant terminology.

Once you move from such background sources into sources which are actuallydefending a position on your subject, you should begin reading for valid arguments.First identify the conclusion the author of the source is defending. If there are severalconclusions, identify the one which is most relevant to the resolution you're debating.Rarely will useful sources on a given topic be defending or denying exactly yourresolution. Instead, they may be addressing a closely related area. For example, if you

are searching for arguments on the resolution that in the U.S., the use of race as adeciding factor in college admissions is just, you may run across Matt Cavanagh'srecent book Against Equality of Opportunity. Cavanagh is writing about the justdistribution of jobs in Great Britain, but many of his arguments could be applied to thedebate over U.S. college admissions. You should study any argument you think mightbe relevant to your resolution, even if its conclusion does not match the resolutionperfectly.

When you find a relevant argument in prose, you should apply your understanding offormal logic to analyze the argument into numbered premise-conclusion form. Thisprocess is difficult to master, but it will greatly enhance your ability to understand (and,

eventually, to attack and defend) arguments.

In the course of explaining valid argument forms, we have used italicized letters (p, q,and so forth) to symbolize propositions. When you are formalizing real arguments, donot use letters to stand for propositions. The purpose of formalizing an argument is tograsp its substance-exactly what premises support a particular conclusion-so youshould write out the relevant premises and conclusion in normal English.

Most authors will not express their premises in conditional (if-then) sentences, so youwill need to paraphrase in order to display the argument's logical structure. And sincemost authors do not state premises they assume will be obvious to their audiences, you

will also have to make these suppressed premises explicit. That's OK as long as youare careful to make your reconstruction of the argument faithful to the author's originalideas. Your goal is simply to understand exactly how the author's argument works.

As suggested above, it is easiest to begin this analysis by identifying the argument'sconclusion. It is especially important at this stage to record the author's preciseconclusion rather than your debate resolution (or its negation), if the two differ. If theargument's conclusion doesn't quite match your resolution, you can think about how

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they might be reconciled at a later stage. But at this stage you will distort the author'sargument if you try to shoehorn it to fit your immediate debate needs.

Once you have identified the conclusion, work backward to find the other premises. Forexample, if the conclusion is the simple proposition r, then look next for a premise which

you can express as the conditional q

r. Does the author also straightforwardly assertq? If so, you have a complete MP argument. But perhaps the argument is morecomplex, and the author derives q only from the further premises pq and p. As we sawin the first article, a valid argument may contain any finite number of iterations of MP,MT, or HS. Fortunately, the formal structure of most real arguments is relatively short;but rarely will an argument for an interesting conclusion be a single instance of MP, MT,or HS, so you should be prepared to encounter a bit of complexity.

Often you will find that the premises an author offers for a conclusion fail to support thatconclusion validly. For instance, you may wind up with an argument of this form:

(1) p

q (premise)(2) qr (premise)(3) rs (premise)(4) So ~p (conclusion)

Since (1)-(3) are conditionals, all you can derive validly from them is anotherconditional: ps. But the author has apparently jumped from this conditional to theconclusion ~p. When you find what appears to be a logically flawed argument, your firstimpulse should be to ask whether you have accurately and completely represented theargument. Check your source very carefully to make sure you haven't overlooked ormisinterpreted anything the author has said.

If you remain convinced that you have formalized the argument fairly and completely,then ask yourself what, if anything, could be added to the argument to make it valid. Inour current example, an additional premise ~s, when combined with the conditionalps, would license us (by MT) to infer the author's original conclusion ~p. Sometimesauthors will deliberately take premises for granted if they believe them to be obviouslytrue. This is more common in popular and journalistic writing than in scholarly writing,but it happens everywhere. For instance, a person might argue that gun control isineffective from the premise that if gun control were effective, cities such as Chicagoand New York which have strict gun control laws would have less gun violence thanareas with no gun control laws. The defender of this argument may just take it for

granted that cities such as Chicago and New York do not have less gun violence. If youfind such an implicit (or "suppressed") premise which is needed to make an argumentvalid, go ahead and write it into your list of premises, noting in parentheses that it isassumed or implicit rather than expressly stated by the author.

Occasionally you will find a published argument which is by itself invalid and whichcannot be patched up by adding an obviously suppressed premise or two. For instance,you may discover that an author is denying the antecedent, inferring ~q from the

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premises pq and ~p. This discovery is obviously well worth making. It allows you toeliminate a possible case argument from consideration, and it also alerts you to the faultin an argument your opponents may try to use. You should not, however, suppose thatbecause a particular argument for a conclusion is invalid, the conclusion is false. All youhave discovered is that one way of trying to reach the conclusion-the way taken by the

invalid argument-does not succeed. There may well be (in fact, certainly are) other, validways of reaching the same conclusion.

The more you research, the more arguments you can find and formalize. Formalizingwill help you to understand the arguments much better than you would if you just readover them in their original wording. It will often be harder than you initially expect, butyou will probably feel a sense of accomplishment and mastery when you have capturedan argument and laid bare its structure. You will be in a much better position to comparevarious argument possibilities and construct the arguments you will defend in your case.With enough practice, you can learn to formalize arguments in your head as you read orhear them, vastly increasing your power as a debater.

III. Contention MappingWhen you have read and analyzed enough arguments to give you a good feel for themain options on each side of the resolution, you are ready to begin mapping casecontentions. This process can be very difficult (although it will be much easier if youhave carefully analyzed the arguments from your research), but the guiding principlehere is simple: Each contention should be a single valid argument which concludes inthe resolution or its negation.

If your research has gone well, or if you have a strong imagination, you should have

more argument possibilities on each side than you can use in a single case. For mostdebaters, novice and varsity, it is best to map out all of the possible constructivearguments for each side. (An argument is constructive just in case its conclusion is theresolution or its negation.) You can make the most informed choices between possiblearguments when you can compare them in the kind of detail a formal premise-conclusion outline reveals.

Here, too, it is safest and easiest to start with the conclusion and work backward. Theconclusion of every constructive argument on a given side will be the same: theresolution (if you are affirmative) or the denial of the resolution (if you are negative).What comes next, "after" the conclusion (if you work backward)? A conditional (if-then)

premise which has the conclusion as its consequent. I.e., if your conclusion is theproposition q, the first premise you construct should be of the form pgq for someproposition p. The trick is to figure out what proposition to use for the antecedent of thisconditional.

Suppose, for example, that you are mapping affirmative arguments for the resolutionthat "The United States is morally obligated to mitigate international conflicts." You havecome across several authors who argue, in various ways, that the U.S. should mitigate

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conflicts because the U.S. has promised to do so. How can you map the argument? Youknow the conclusion will be simply the resolution. And you know that the first premiseyou map, working backward, will be a conditional statement which says: If p, then[resolution]. What should you fill in for p? Given your initial argument idea, the obviouscandidate for p is "the U.S. has promised to mitigate international conflicts." So your

complete premise is, "If the U.S. has promised to mitigate international conflicts, thenthe U.S. is morally obligated to mitigate international conflicts." So far, so good.

What more is needed for a valid argument? You cannot conclude q from pq alone.You need at least one further premise, p, added to your conditional to give you a validinstance of modus ponens. So you need to add as a premise, "The U.S. has promisedto mitigate international conflicts." If you stop at this point, you have mapped a singlevalid argument:

(1) The U.S. has promised to mitigate international conflicts. (premise)(2) If the U.S. has promised to mitigate international conflicts, then the U.S. is morally

obligated to mitigate international conflicts. (premise)(3) So the U.S. is morally obligated to mitigate international conflicts. (conclusion)

There is nothing logically wrong with this argument as mapped. However, you may findit useful to supplement the argument by adding more premises which clarify the detailsof the argument as you plan to defend it. The easiest way to supplement an argument isto ask yourself what you would say to an opponent who asked, about any of yourpremises, why that premise is true. You can usually answer this question by adding twoor more new premises to support your original premise.

What if someone asked why the first premise of the argument above is true?

Presumably the research that inspired the argument has given you a detailed idea ofhow exactly the U.S. promised it would mitigate international conflicts. Perhaps the U.S.signed a treaty (we'll call it "Treaty T") in which it promised to "use all reasonablemeans, diplomatic and military, to restore peace to war-torn regions of the world."Assuming you have good evidence (in this case, a copy of Treaty T) to support yourclaim, you could represent your original (1) as the conclusion of further premises, likeso:

(1') The U.S. signed Treaty T.(premise)(1'') If the U.S. signed Treaty T, then the U.S. promised to "use all reasonable means,diplomatic and military, to restore peace to war-torn regions of the world." (premise)

(1''') If the U.S. promised to "use all reasonable means, diplomatic and military, torestore peace to war-torn regions of the world," then the U.S. promised to mitigateinternational conflicts. (premise)(1) The U.S. promised to mitigate international conflicts. (premise, from 1', 1, 1')(2) If the U.S. promised to mitigate international conflicts, then the U.S. is morallyobligated to mitigate international conflicts. (premise)(3) So the U.S. is morally obligated to mitigate international conflicts. (conclusion)

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Now you can see how you might supplement a simple premise p or q, such as premise(1): by making it the conclusion of further applications of modus ponens (or modustollens). When you do this, the original premise remains part of the argument, but you

justify it by making explicit the premises supporting it.

What about a conditional premise like (2)? How might you support that premise? Again,think about what you would say if someone asked you why (2) is true. To supplement aconditional premise, you will need to add two new conditional premises to the argument.Here is the recipe:

Write two new conditionals. Make the antecedent of the original conditional theantecedent of the first new conditional. Make the consequent of the original conditionalthe consequent of the second new conditional. Finally, find a new proposition to serveas both the consequent of the first new conditional and the antecedent of the secondnew conditional.

So you are supplementing a statement of the form p

q with two statements of the formpr and rq. These two new statements yield the original pq by an application ofhypothetical syllogism.

Let's look at how this recipe works in practice. Think about the question, "Why believethat if the U.S. promised to mitigate international conflicts, then the U.S. is morallyobligated to mitigate international conflicts?" This question really amounts to somethinglike, "Why is there a moral obligation to keep promises?" To answer the question, youare probably going to have to appeal to a moral theory. Fans of strict promise-keepingtend to like Kant's theory, so we will suppose that's your theory of choice. According toKant, what is wrong with deliberately breaking a promise is that doing so cannot

consistently be willed as a universal law-i.e., breaking promises violates Kant's so-calledcategorical imperative. Given Kant's reason for thinking that we are morally obligated tokeep promises, we can supplement premise (2) by adding:

(2') If the U.S. has promised to mitigate international conflicts, then the U.S. mustmitigate international conflicts if it is to act in accord with Kant's categorical imperative.(2'') If the U.S. must mitigate international conflicts if it is to act in accord with Kant'scategorical imperative, then the U.S. is morally obligated to mitigate internationalconflicts.

The two new premises (2') and (2'') justify (2) in our argument, making more explicit the

thought behind that original premise. In an actual contention, as opposed to thisargument map, you would want to explain in more detail just what Kant's categoricalimperative is, why anyone should care about it, and why it requires promise-keeping.

Expanded in the way we have now suggested, what began as a two-premise argumentnow has seven premises: (1'), (1), (1'), (1), (2'), (2''), and (2). Both the short and longerversions are equally valid. But the longer version will be more useful when you come towriting the actual contention, because it makes the content of the argument more clear

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and detailed. We could go on asking the same "Why?" questions of the new premises inour longer argument and supplement the argument even further. We won't do that here,assuming you see roughly how the expansion process works. Keep expanding yourmap of an argument until the thought behind the argument would be clear to someonewho carefully reads through the premises and conclusion.

At this stage, you have found (or created) an idea for a constructive argument and havemapped that idea into valid premise-conclusion form. Your next task is to classify thepremises of your mapped argument to get some sense of what kinds of support youwould need if you were to adopt the argument as part of your case position. We canthink of premises as falling into three broad categories: empirical, normative, anddefinitional.

Empirical premises are claims which could, in principle, be tested scientifically or withthe physical senses. That January is colder than June, that Elvis is alive in Arizona, andthat free trade hurts American wages are examples of empirical claims. (The first is true;

the second, false; and the third, contested.) Debaters should especially note that allcausal claims (claims of the form "X causes Y" or "if X occurs, then Y subsequentlyoccurs") are empirical claims.

Normative (or evaluative) premises make claims about what is good or bad, moral orimmoral, valuable or valueless. They are not typically subject to scientific or sensoryvalidation. Examples include that cheating is wrong, that justice requires economicequality, and that citizens ought to vote. Almost all LD resolutions are themselvesnormative claims.

Definitional (or analytic) claims are true in virtue of the meanings of their words; they are

not substantive descriptions of any chunk of physical or moral reality. That all aunts arefemale, that every whole number is either odd or even, and that a treaty is a promiseare all analytic claims. At most, they inform someone of the structure of our conceptsand language. You might think that definitional claims are always uncontroversial, butthis is not so. Is it true that human genetic engineering is, by definition, the curing ofgenetic diseases? This is a very controversial claim, and a debater lost the final roundof the Glenbrooks tournament several years ago when he built an argument on thispremise but could not defend it with an actual definition from a legitimate source.

Many philosophers now believe such distinctions among types of propositions aremisleading. However, I believe they are useful for thinking about the premises of debate

arguments, and I hope you have a rough feel for what kinds of claims fall under eachcategory. Sometimes it will be hard to tell into which category a given premise falls. Buteven if a premise straddles two of the categories, it can be helpful to know at least that itdefinitely does not belong to the third.

As an exercise, let's run through the seven premises of our last argument, classifyingthem by type. If you were doing this on paper or on a blackboard, you could simply writean "E," "N," or "D" next to each premise when you knew its type.

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(1') The U.S. signed Treaty T.

This premise is clearly empirical. It is a simple assertion of historical fact and should beconfirmable by checking the relevant documents.

(1'') If the U.S. signed Treaty T, then the U.S. promised to "use all reasonable means,diplomatic and military, to restore peace to war-torn regions of the world."

This premise straddles the fence between empirical and definitional. On the one hand,we would probably need to find documentary evidence of just what Treaty T said inorder to assess the truth of the premise. On the other hand, the premise could be takenas simply defining (in part) the content of Treaty T-signing Treaty T includes thatpromise because that's just what Treaty T is.

(1''') If the U.S. promised to "use all reasonable means, diplomatic and military, torestore peace to war-torn regions of the world," then the U.S. promised to mitigate

international conflicts.

This premise is clearly definitional. It simply translates the language of the treaty into thelanguage of the resolution.

(1) The U.S. promised to mitigate international conflicts.

This premise does not fall under any of our three headings, because it is not, strictlyspeaking, a premise. It is a subconclusion of premises (1), (1), and(1). It does notaim to supply new information but simply helps the audience grasp the logical/conceptual relationships among other premises. But if (1) were not a subconclusion and

instead functioned as a free-standing premise, it would clearly be empirical, because itis a claim about a verifiable action the U.S. has taken in history.

(2') If the U.S. has promised to mitigate international conflicts, then the U.S. mustmitigate international conflicts if it is to act in accord with Kant's categorical imperative.

Classifying this premise is tricky because of the intricacies of Kant's philosophy. If Kanthad asserted (2'), he probably would have meant it as a definitional truth: Once aperson understands the concept of a promise, he will be able to see that it would belogically impossible to will as a universal law that promises be broken.

(2'') If the U.S. must mitigate international conflicts if it is to act in accord with Kant'scategorical imperative, then the U.S. is morally obligated to mitigate internationalconflicts.

This premise is clearly normative. It makes a substantive claim about the content ofmoral obligations, namely, that a nation is morally obligated to act in accord with thecategorical imperative.

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(2) If the U.S. promised to mitigate international conflicts, then the U.S. is morallyobligated to mitigate international conflicts.

Like (1), (2) is no longer really a premise, because it is now a subconclusion from (2')and (2''). But if (2) were a free-standing premise, it would clearly be normative.

(3) So the U.S. is morally obligated to mitigate international conflicts. (conclusion)

The conclusion is, obviously, a normative claim. It's the resolution, and LD resolutions(as we've said) are normative claims.

You should classify the premises of all the possible case arguments you map. Whenyou think about which one or two (never more than three) arguments to build into yourcase, you should compare the varying empirical, normative, and definitional burdensyou'd be assuming by adopting each argument. It will not be enough in the case merelyto state your premises and explain how the conclusion logically follows. You will also

have to persuade your audience that each premise is true, and some premises areeasier to sell than others.

Any empirical premise is going to need empirical evidence to support it. That means ifyou don't have good evidence to back a premise at the time you first map an argument,you will have to find good evidence if you decide to include that argument in your case.LD students are especially prone to think that causal claims can be supported "logically"rather than empirically. This is false. Logic does not have the resources to prove causalstatements about events in the world. (If you do not believe this, read Section IV ofDavid Hume's first Enquiry.) When someone says that "it's just obvious" that one type ofaction or event will cause another type of action or event, all that person really means is

that it seems obvious to him. There is no way to know what actions will cause whateffects without empirical investigation. Particularly when large-scale social phenomenaare at play (as they often are in LD resolutions), armchair predictions about causes andeffects have a very bad track record. You must have expert evidence that the worldreally works the way you claim it does if you expect your empirical premises to becredible to your audience.

Good empirical evidence is hard to find, and the more empirical premises an argumenthas, the more evidence you will need. Because consequentialist arguments depend onthe actual empirical results of an action to determine its morality, such arguments willtypically require more empirical evidence than deontological or other non-

consequentialist arguments require. Many debaters think that consequentialistarguments are somehow more objective and therefore easier to defend than aredeontological arguments. But there is nothing in the structure of consequentialistarguments that should lead you to believe that. Any valid argument for a normativeconclusion is going to contain at least one normative premise, and this is just as true ofvalid consequentialist arguments as of others. The only difference betweenconsequentialist and non-consequentialist arguments on this score is that the formeradd controversial empirical premises to their controversial normative premises.

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Debaters who wish to minimize their reliance on empirical evidence may want to avoidconsequentialist arguments, especially consequentialist arguments with multiple causalpremises.

Notice that our sample argument above has an empirical premise (1') even though it is

not a consequentialist argument. However, you should be able to see immediately thatnot all empirical premises are created equal. Premise (1') requires evidence, but theevidence will be an uncontroversial report of a public event, the signing of a treaty. Thiskind of empirical evidence is much easier to find and to defend than is evidence on(say) the climatic effects of carbon dioxide or the deterrent effects of capital punishment.

Normative premises will not require empirical evidence, but they will typically requirepersuasive explanation and perhaps a vivid illustration. Supporting a normative premiseis likely to require more hard thought than any other element of an argument. Sounderstand, when you compare argument options, that you will have to defend yournormative premises in the case.

Definitional premises vary greatly in the kind and amount of support they require.Sometimes appeal to a standard dictionary (or even to the linguistic intuitions of youraudience) is enough support for simple definitional claims. At other times, especiallywhen a claim concerns technical or otherwise unfamiliar concepts, you will need expertevidence.

Finally, if a "premise" is really just a subconclusion of previous premises, you might wantto explain how it follows so that your audience can fully grasp the logical connectionsyou are claiming.

Since this is not an article on casing per se, I will not go into detail on how the varioustypes of premises should be supported (although I offer a few tips in Part V below). Butit is important, before selecting your case arguments, to understand what kinds ofpremises each argument includes and to have a rough sense about what kinds ofsupport each type of premise will require.

If you end up choosing more than one argument for your case, check to be sure thepremises of all your arguments are compatible. You do not want to defend a premise inone argument which you deny a few paragraphs later in a different argument. Beespecially certain that the normative premises of all your arguments more or less tallywith each other. It is not necessary to have the same normative premises in each

argument (although this is often possible, and a good idea). But make sure you are notendorsing incompatible moral theories at different points in your case, and that you canexplain, if asked, how a person could hold all your normative premises as part of acoherent moral outlook.

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IV. Value Premise(s)In many regions, LD cases are expected to begin with a statement of a "value premise"and "criterion." Each of these items is expressed by a single word or phrase; together,they are supposed to provide standards by which judges should evaluate subsequentarguments. Sometimes the value premise is drawn straight from the resolution, as when

the resolution mentions morality or justice. At other times, the value premise is chosenby the debaters as the single most relevant axis of evaluation for a generic "ought"statement. The criterion is typically thought of as a more detailed specification of thecontent of the value premise. For example, if a debater proposes a value premise ofmorality, she might go on to propose a criterion of maximizing the balance of pleasureover pain. The point would then be that the resolution is true if the course of action itprescribes is moral, and that that course of action is moral if it maximizes the balance ofpleasure over pain. This is only a rough sketch of a very confused and confusing area ofLD theory.

I am going to challenge the traditional value premise/criterion model, but I want first to

acknowledge its merits. It is the model I was taught and used as a debater. It hasserved a valuable function by imposing order on cases that might otherwise have beenunshapely piles of unrelated points. It can give judges a helpful focus for assessing therelevance of various claims at the end of a round. I have myself written a sympatheticexposition of the model (see the November 1997 Rostrum).

However, the model has many shortcomings. First, it is notoriously hard to say preciselyhow the value premise is related to the resolution and how the criterion is related to thevalue premise. Debaters often speak of the value premise as "supporting" the resolutionor of the criterion as "fulfilling" the value premise, but it is hard to know just what thesedescriptions mean.

Second, because value premises and criteria are nouns or noun phrases, it is oftenunclear how they connect with the claims unique to either side of the resolution.Suppose the resolution is that "The possession of nuclear weapons is immoral." If theaffirmative says, "My value premise is morality," what should this lead us to expect fromhis arguments? Will he be claiming that someone or some action is moral? Theresolution would lead us to think the affirmative will be claiming that something isimmoral. If so, why is the affirmative's value premise morality? If the affirmativesucceeds in proving the possession of nuclear weapons immoral, he won't have proventhat any person or action is moral. Instead, he will have shown that a certain action isnot moral. So in what sense will anyone have "fulfilled" or "upheld" morality? And who

would have done it-the affirmative debater, or the (non)possessors of nuclear weapons?

A third problem with the traditional model is that it does not distinguish betweennecessary and sufficient conditions for satisfying a value. Suppose the value premise ismorality and the criterion is respecting innocent life. Does that mean that if an action ismoral, then it respects innocent life? Or does it instead mean that if an action respectsinnocent life, then it is moral? In the former case, respecting life would be a necessarycondition of morality; in the latter, a sufficient condition. The simple terms that compose

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a traditional value premise and criterion obscure this important logical distinction.

A fourth problem, and perhaps the central problem, with the traditional model is that itseparates the value premise and criterion from the contentions, where the substantivearguments are thought to be. Since many debaters are confused about how the value

premise and criterion are supposed to function and they have what seem to be self-contained arguments in their contentions, they end up ignoring the value premise andcriterion and focusing only on contention arguments. Defenders of the traditional modelwill say (rightly) that this results from a misunderstanding of the model. However, thatmisunderstanding is widespread enough that the model is falling out of use amongpeople who find it too unwieldy to apply.

These disadvantages give us reason to search for a better way of organizing LDarguments. To anyone wedded to the traditional model I have been criticizing, it shouldbe a striking fact that moral and political philosophers who write about some of thesame issues debated in LD never appeal a value premise or criterion (in the LD sense).

Instead, their arguments resemble the formally valid sets of premises and conclusionswe have examined above.

The key point to notice is that there are no missing steps in a formally valid argument-there is nothing left that a value premise or criterion could add. The premises of a validargument are sufficient to prove its conclusion, and if that conclusion is the resolution orits denial, the argument proves enough for LD purposes. I suggest that LD cases becomposed of valid deductive arguments with no logically independent value premises orcriteria. So the model I am proposing really amounts to the model of deductiveargument that philosophers have been using for centuries.

This model avoids the four problems with the traditional value premise/criterion model Ioutlined above. I will not explain in detail how, but interested readers can examine avalid argument in the light of each problem and see that the problem does not arise forthe argument.

Do I suggest abandoning all talk of value premises? No, because many judges areexpecting to hear debaters offer value premises and may penalize debaters who do not.(It may also be worth noting that the NFL's official "Lincoln-Douglas Debate Guidelines"state that LDers should establish value premises and values criteria. They go on todefine values criteria as "a system upon which to judge values," but they do not sayanything very helpful about what that means.) Fortunately, the valid argument model

gives us a ready candidate for a revised version of the value premise that is not logicallyirrelevant to the constructive arguments. Where r is the conclusion of a constructiveargument, the value premise will generally be the conditional premise in which rappears as consequent (if the argument employs modus ponens) or in which ~r appearsas antecedent (if the argument employs modus tollens). Because our sample argumentabove employed modus ponens, the value premise would be (2), since this is thepremise whose consequent is the conclusion (the resolution) which we are proving.

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A major difference between this model and the traditional model is that the valuepremise is now a complete sentence rather than a noun or noun phrase. This is all tothe good, since a premise is, by definition, a sentence or proposition. In fact, it ismysterious how a word or phrase could ever have come to be called a value premise inthe first place. While the new value premise avoids the problems with the old model, it

can still serve a similar function if it appears near the beginning of a case or argument. Itstill provides the audience with a standard or goal to use in evaluating the success ofthe argument. It tells listeners when they will have a sufficient reason to conclude thatthe resolution is true-namely, when the debater has shown the antecedent of the valuepremise to be true (or, in the case of a modus tollens argument, the consequent of thevalue premise to be false).

The fact that this value premise is pulled straight out of a valid argument also callsattention to the fact that it must be explained and defended just like any other premise ifthe argument is to succeed. Many debaters using the traditional model simply announcea value premise and criterion without really justifying their selection. It is easy to get by

with this if the value premise and criterion play no essential role in the structure of one'sarguments. But in the new model, constructive arguments will not be convincing unlessthe value premise is also convincing. This premise will always be a normative premise,and it will typically be the most important and controversial normative premise in anargument. Therefore, the value premise will often merit extensive explanation andsupport in its own right. Depending on the structure of the argument, it may beappropriate to spend more time arguing in support of one's value premise than insupport of any other single premise of one's argument. Establishing this premise willoften be the most philosophically challenging task of an LD case. This model makesbetter sense of the importance many judges place on "the standards debate." These

judges want to see debate over conflicting normative premises, and the new model is

well suited to promote just such debate.

A case that contains more than one independent argument may have more than onevalue premise. If separate case arguments require separate value premises, eachpremise should be stated and defended separately. Many traditionalists will view thepossibility of multiple value premises in a single case with suspicion, and I share theirconcern. A case with multiple value premises may end up sounding incoherent or eveninconsistent. I am inclined to think that for most students most of the time, developingarguments under a single value premise is the best strategy. I have found that LDstudents invariably regard themselves as exceptions to such generalizations; to anystudents reading this, I can only say, I mean you-you should probably try to construct

cases with a single value premise.

Recognizing the rare situations when multiple value premises might be appropriaterequires a skillful sensitivity to the particulars of combinations of arguments which Icannot impart through this article. Here is the extent of what I can say in general terms:Multiple value premises are likely to work best in cases which seek to prove that somepractice is immoral or not justified. There are many ways for actions to go wrong, sodistinct value premises might identify distinct sufficient conditions for an action's

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immorality or unjustifiability; each independent contention could then prove the actionimmoral or unjustified by showing it failed to satisfy the requirements stated in one ofthe various value premises. But, as I say, it is usually safer and clearer to choosecontention arguments that work together under a single value premise.

I have proposed a revised understanding of the value premise, but is there any place fora revised version of the criterion in my model? Yes and no. Yes, in the sense that valuepremises of the kind I am recommending often function as criteria: they give judgesstandards or goals by which to measure an argument's success. In fact, often the new-style value premise will contain a phrase that, by itself, could function as an old-stylecriterion. For example, in (2) above, the notion of keeping promises, which occurs in theantecedent, might serve as a criterion for morality, which occurs in the conclusion.When the resolution itself mentions a value term (such as "morally obligated" in ourexample), the complete new-style value premise will contain both the old-style valuepremise and the old-style criterion.

But when the resolution does not mention a value term, there may be two normativepremises, one of which is naturally treated as the value premise and the other of whichis naturally treated as the criterion. Suppose, for example, that instead of directlymentioning moral obligation, our resolution said simply that the U.S. ought to mitigateinternational conflicts. Now what had been a single premise (2) may be split into twoseparate premises: one which says that if the U.S. is morally obligated to mitigateconflicts, then the U.S. ought to mitigate conflicts, and one which says that if the U.S.promised to mitigate international conflicts, then the U.S. is morally obligated to mitigateinternational conflicts. The first of these premises might be called the value premisesince it proposes moral obligation as the relevant ought-making relationship. And thesecond might be called the criterion since it proposes promise keeping as a necessary

condition of satisfying one's moral obligations.

In situations of the first kind I discuss, where a value term appears in the resolution, Ibelieve proposing a criterion distinct from the value premise would be unnecessary andconfusing. The value premise already contains the term which would have been treatedas the criterion in the old paradigm, so nothing of substance is lost by simply droppingtalk of the criterion. In these cases, the criterion is simply part of the value premise.

However, in situations of the second kind I discuss, where the resolution does notmention a value term (typically using an open-ended "ought" instead), it may be wise toretain a distinct criterion. In these cases, the value premise and criterion will each be a

complete conditional premise of the argument. Where r is the conclusion (the resolutionor its negation), qr will be the value premise, and pq will be the criterion. If this is notimmediately clear to you, study the example from the paragraph before last to see howsuch new-style value premises and criteria might be related. Like so much else indebate, deciding whether to retain a distinct criterion requires careful judgments aboutparticular resolutions and arguments.

Finally, is there a way to present genuine premises as value premises and/or criteria

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without alienating traditional judges who expect words and phrases rather thansentences? I believe there is. A debater may simply pick the most value-laden word orphrase from her value premise or criterion and state this term as the (old-fashioned)value premise or criterion. She may then follow this word or phrase with a completestatement of the full premise. For example, a debater might say, "My value premise is

respecting gender equality. In other words, if pornography disrespects gender equality,then government censorship of sexually explicit materials is justified." This statementshould then be followed by an explanation and defense of the premise.

V. Contention DevelopmentThe toughest thought-work of case construction is now complete: extensive researchhas uncovered numerous argument ideas, and the best of these have been formallymapped and analyzed to show exactly which premises are required to sustain theconclusion and also what kinds of support will be needed to sustain the premises. One,two, or at most three of these mapped arguments have been selected for inclusion in

the constructive speech itself, and authentic value premises have also been identified.The work that remains to transform these skeletal arguments into a presentable LDcase falls largely into the domains of rhetoric and composition-subjects we will not takeup here. But the logic-centered model of argument does have a few implications for thisfinal stage of casing which we should notice.

The first implication is one at which I have already hinted: Each contention should be adistinct valid argument concluding in the resolution or its negation. This means that ifonly one really strong constructive argument emerges from your research andbrainstorming, you should expect to have a one-contention case. Some LDtraditionalists have a fetish for two- or three-contention cases and will split a single

argument into more than one contention if necessary. I cannot see what is gained bythis practice, and I have often seen something lost. Students instinctively think of theircontentions as free-standing argument units, and when pressed for time, they willsometimes abandon one contention (usually the last of two or three) in order to defendanother. In the case of truly independent arguments, this strategy, while not ideal, neednot be disastrous. But in the case of a single argument spread out over severalcontentions, the maneuver is fatal. No one contention in such a case provides a self-contained reason to believe or disbelieve the resolution. If one contention falls, theothers are worthless. If that same single argument had been presented as onecontention instead of two or three, the student would have been less likely to think ofany part of the argument as dispensable.

Of course, the ideal is to present two or three truly independent arguments to affirm ornegate the resolution. It is worth spending a lot of time in research and planning to try todiscover two or three such arguments. But sometimes there really is only one excellentconstructive argument, and to include another one or two mediocre arguments in thecase would dilute the power of the strong argument. Since different arguments willappeal to different people, you should run your contention candidates by a variety ofpeers and adults (including plenty from outside debate) before you narrow your case to

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a single argument. It will often be worth including a second or third argument which youpersonally find uninspiring if other people find it persuasive.

The second implication of logic-centered argumentation for case writing is that eachpremise of a valid argument should be explicitly stated and defended. The key

normative premises may be stated and defended as value premises before thecontentions proper begin. But each premise should find its way into the casesomewhere.

A premise need not be stated exactly as it appears in the argument map. To ensureformal validity, the argument map forced you to state most premises as if-thenconditionals. Most such conditionals can be phrased more naturally in your case asnon-conditionals. For example, consider this premise of our specimen argument above:

(1'') If the U.S. signed Treaty T, then the U.S. promised to "use all reasonable means,diplomatic and military, to restore peace to war-torn regions of the world."

No one would really talk like this in a persuasive speech. You could communicate thesame point of the conditional (1'') with this non-conditional sentence:

By signing Treaty T, our nation promised to abide by all of its provisions, includingthe requirement that we, quote, "use all reasonable means, diplomatic andmilitary, to restore peace to war-torn regions of the world."

Anytime you rephrase a premise from your argument map, you should be very carefulthat your rephrasing communicates exactly the same thought as the old premise. Youwill have preserved that equivalence of meaning if, roughly, the old premise is true only

if the new premise is true, and the new premise is true only if the old premise is true.

Note that premises should be stated and defended. Occasionally an argument willcontain an especially obvious premise that needs no defense, other than one or tworestatements in different words to make the point clear for listeners. But most importantpremises, including definitional premises, are controversial to one degree or anotherand should be defended. A crude rule of thumb is that each premise should receive aparagraph's worth of explanation and defense. This rule is crude because a fewpremises (as we have noted) will require little or no defense, whereas some premisesmay require many paragraphs to establish. Sometimes defending a premise requiresconstructing a mini-argument of which the premise is the conclusion. These further

arguments can normally be incorporated into expansions of the argument map, asillustrated above.

At this point, clever readers may wonder if it's really possible to defend every premise. Ifa premise is defended with a further argument, won't that argument itself containpremises which must be defended, and so on, to infinity? This reaction is correct-it isimpossible to deductively prove every premise on which an argument depends. At somepoint, the formal arguments must end, and the base-level premises must be treated as

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postulates (OK if they are obviously true) or motivated by non-argumentative appeals(e.g., appeals to moral intuitions or emotions). Some people think LD should be about"pure logic," but that is not possible as long as LD is supposed to yield substantiveconclusions. To get off the ground, every argument must begin with some premises thatare simply asserted. No substantive conclusions follow from logic alone; this is just a

fact about logic, not a shortcoming of LD.

Empirical premises will require empirical evidence, although you will keep a better gripon your audience's attention if you explain most of the empirical background in your ownwords and quote outside authors only briefly to confirm crucial details or conclusions.Reading long quotations is never impressive. It suggests the speaker has simply liftedhis arguments wholesale from other sources and may not really understand theresearch. Whenever you use empirical evidence, you should sandwich it between yourown explanation of its source, content, and significance for the argument. Evidence isnot self-interpreting. You must be scrupulously accurate in the ways you characterizethe claims of your cited authors. It is tempting to exaggerate a source's limited claim so

that it better supports the sweeping claim of your premise, but doing so is dishonest,and responsible judges will not reward the practice.

Normative premises will require non-empirical support. Sometimes quoting a particularlyclear or persuasive source (such as a philosopher) can bolster such a premise, butoften you will have to resort to your own persuasive powers. One of the classic ways inwhich philosophers argue for their own normative premises is by the use of examples oranalogies. Most of the normative principles that might apply to a given resolution arebroad enough to apply to other issues as well. One of the traditional purposes of moraland political philosophy is to furnish a relatively small number of principles that will applyto many different situations. So chances are, the normative principle to which you

appeal has a wider application. Pick some obvious non-resolutional situation to whichthe principle might apply. Describe a possible moral decision in that situation aboutwhich you and your audience will share moral intuitions and about which your princplegives the proper outcome-the outcome that matches everyone's intuitions. This non-resolutional example may then count as some evidence that the normative principle iscorrect.

For definitional or analytic premises, you will need, at a minimum, to explain in full detailjust why the premise is necessarily true. When appropriate, you should also quoteauthoritative definitions to support your claim. Consider a premise as trivial as, "If Johnis a bachelor, then John is a man." You might defend this premise by saying, "A

bachelor is, by definition, an unmarried man. All bachelors, therefore, are men, so ifJohn is a bachelor, he's a man, too." This explanation did not cite authoritative sources,because it assumes that every adult English speaker knows the definition of "bachelor."But if the claim were about a more technical or obscure concept, such as geneticengineering, the Second Amendment, or globalization, then quoting an expert sourcethat described the concept would probably be necessary.

Ultimately, there is no formula for adequately explaining and defending each premise of

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an argument. Distinguishing the three types of premises as we have can be some help,but each premise will require a unique treatment. The best way to see how differentsorts of premises can be supported is to study how they actually are supported byscholars in the relevant disciplines or by high-quality public intellectuals.

By thinking of contentions as arguments and premises as the basic units of contentions,you can avoid the confusion that debaters often inject into rounds by their attempts tobreak contentions into different "subpoints." It is often unclear just how the varioussubpoints are distinguished from one another and how they are functioning in aconstructive argument. Anyone who wants to retain talk about "subpoints" in his or hercases should probably think of each premise as a distinct subpoint. I don't find mostexplicit subpoint talk helpful or attractive, but people who do should conform such talk tothe logic of their arguments.

A third implication of the logic-centered approach for contention building is that premisesmust be presented in an order the audience will find persuasive and easy to follow. You

might think that the best order of premises for any argument will be the order you haveused in your argument map, but this is not always so. The argument map itselfrepresents only one valid formulation of the argument; the same premises could havebeen ordered differently and still have yielded the same conclusion. So the map doesnot settle much about the order of presentation.

We have already seen that where q is the conclusion of your argument, the conditionalpremise pgq in which q occurs as the consequent will typically be the value premise thatis appropriately presented before the other premises of the argument. Apart from LDconvention, there is a good rhetorical reason to present this premise first. By doing so,you are setting a fixed target for yourself. Consider this simple modus ponens

argument:

(4) Capital punishment deters crime. (5) If capital punishment deters crime, then capital punishment is morally

justified. (6) So capital punishment is morally justified.

Here, (4) is an empirical premise, while (5) is clearly normative. If you presented theargument in just the order it is mapped above, some listeners might have the followingreaction: "He just researched what capital punishment does, discovered it deters crime,and then cooked up an ad hoc moral principle to conclude that if capital punishment

does whatever it does, it must be moral." In other words, it may look as if you have set amoving target for yourself-whatever capital punishment does, that's what you claimmakes it morally justified. If instead you present (5) before (4), your approach looksmore principled. It looks as if you have first identified what quality makes a punishment,any punishment, morally justified, and then gone out into the world (so to speak) to seeif capital punishment does, in fact, have that quality. The substance of your claims hasnot changed, but the argument may be more effective for some listeners.

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As far as the other, non-value premises go, you will have to use your best judgmentabout the most effective order of presentation. Generally, you should be moving more orless sequentially through your argument map, but sometimes you may want to workfrom start to finish, other times from finish to start. Before you begin actually writing thecontention, you may want to write each premise on a separate slip of paper and then

experiment with different orderings to see which will make the argument mostaccessible to your audience.

A fourth and final implication of the logic-centered approach for case writing is that youmust make the logical structure of your arguments clear to your audience. You cannot

just assume that by presenting and defending a set of premises which do, in fact, entailan announced conclusion, you will have persuaded your audience that those premisesreally do entail that conclusion. Because you have spent much time researching andformulating the argument and have studied it in skeletal form, it is easy for you to seethe logical relationships among its various parts. But your listeners are meeting theargument for the first time when they hear your case, and they may not be accustomed

to tracing the logical implications of different premises.

The best way to ensure that your audience grasps the logical character of yourargument is t

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Logic In LD