{95} Appendix II
Definitions
Some arguments require attention to the meaning of words. Sometimes we may not know the established meaning of a word, or the established meaning may be specialized. If the conclusion of your argument is that “Wejacks are herbivorous,” your first task is to define your terms, unless you are speaking to an Algonquian ecologist.11 If you encounter this conclusion elsewhere, the first thing you need is a dictionary.
Other times, a term may be in popular use but still unclear. We debate “assisted suicide,” for example, but don’t necessarily understand exactly what it means. Before we can argue effectively about it, we need an agreed-upon idea of what we are arguing about.
Still another kind of definition is required when the meaning of a term is contested. What is a “drug,” for example? Is alcohol a drug? Is tobacco? What if they are? Can we find any logical way to answer these questions?
A neighbor of mine was taken to task by the city’s Historic Districts Commission for putting up a four-foot model lighthouse in her front yard. City ordinances prohibit any yard fixtures in historic districts. She was hauled before the commission {96} and told to remove it. A furor erupted and the story got into the newspapers.
Here the dictionary saved the day. According to Webster’s, a “fixture” is something fixed or attached, as to a building, such as a permanent appendage or structural part. The lighthouse, however, was moveable—more like a lawn ornament. Hence, it was not a “fixture”—seeing as the law did not specify any alternative definition. Hence, not prohibited.
When issues get more difficult, dictionaries are less helpful. Dictionary definitions often offer synonyms, for one thing, that may be just as unclear as the word you’re trying to define. Dictionaries also may give multiple definitions, so you have to choose between them. And sometimes, dictionaries are just plain wrong. Webster’s may be the hero of the last story, but it also defines “headache” as “a pain in the head”—far too broad a definition. A bee sting or cut on your forehead or nose would be a pain in the head but not a headache.
For some words, then, you need to make the term more precise yourself. Use concrete, definite terms rather than vague ones (Rule 4). Be specific without narrowing the term too much.
Organic foods are foods produced without chemical fertilizers or pesticides.
Definitions like this call a clear idea to mind, something you can investigate or evaluate. Be sure, of course, to stick to your definition as you go on with your argument (no equivocation).
One virtue of the dictionary is that it is fairly neutral. Webster’s defines “abortion,” for example, as “the forcible expulsion of the mammalian fetus prematurely.” This is an appropriately neutral definition. It is not up to the dictionary to decide if abortion is moral or immoral. Compare a common definition from one side of the abortion debate:
“Abortion” means “murdering babies.”
This definition is loaded. Fetuses are not the same as babies, and the term “murder” unfairly imputes evil intentions to well-intentioned people. That ending the life of a fetus is comparable to ending the life of a baby is an arguable proposition, but it is for an argument to {97} show—not simply assume by definition. (See also Rule 5, and the fallacy of persuasive definition.)
You may need to do a little research. You will find, for example, that “assisted suicide” means allowing doctors to help aware and rational people arrange and carry out their own dying. It does not include allowing doctors to “unplug” patients without their consent (that would be some form of “involuntary euthanasia”—a different category). People may have good reasons to object to assisted suicide so defined, but if the definition is made clear at the outset, at least the contending parties will be talking about the same thing.
Sometimes we can define a term by specifying certain tests or procedures that determine whether or not it applies. This is called an operational definition. For example, Wisconsin law requires that all legislative meetings be open to the public. But what exactly counts as a “meeting” for purposes of this law? The law offers an elegant criterion:
A “meeting” is any gathering of enough legislators to block action on the legislative measure that is the subject of the gathering.
This definition is far too narrow to define the ordinary word “meeting.” But it does accomplish the purpose of this law: to prevent legislators from making crucial decisions out of the public eye.
Sometimes a term is contested. That is, people argue over the proper application of the term itself. In that case, it’s not enough simply to propose a clarification. A more involved kind of argument is needed.
When a term is contested, you can distinguish three relevant sets of things. One set includes those things to which the term clearly applies. The second includes those things to which the term clearly does not apply. In the middle will be those things whose status is unclear—including the things being argued over. Your job is to formulate a definition that
{98} 1. includes all the things that the term clearly fits;
2. excludes all the things that the term clearly does not fit; and
3. draws the plainest possible line somewhere in between, and explains why the line belongs there and not somewhere else.
For example, consider what defines a “bird.” Exactly what is a bird, anyway? Is a bat a bird?
To meet requirement 1, it is often helpful to begin with the general category (genus) to which the things being defined belong. For birds, the natural genus would be animals. To meet requirements 2 and 3, we then need to specify how birds differ from other animals (the differentia). Our question therefore is: precisely what differentiates birds—all birds and only birds—from other animals?
It’s trickier than it may seem. We can’t draw the line at flight, for example, because ostriches and penguins don’t fly (so the proposed definition wouldn’t cover all birds, violating the first requirement), and bumblebees and mosquitoes do (so the proposed definition would include some nonbirds, violating the second).
What distinguishes all and only birds, it turns out, is having feathers. Penguins and ostriches have feathers even though they don’t fly—they’re still birds. But flying insects do not, and neither (in case you were wondering) do bats.
Now consider a harder case: what defines a “drug”?
Start again with the clear cases. Heroin, cocaine, and marijuana clearly are drugs. Air, water, most foods, and shampoos clearly are not drugs—though all of these are “substances,” like drugs, and are all ingested or applied to our body parts. Unclear cases include tobacco and alcohol.12
Our question, then, is: Does any general description cover all of the clear cases of drugs and none of the substances that clearly aren’t drugs, drawing a clear line in between?
A drug has been defined—even by a presidential commission—as a substance that affects mind or body in some way. But this {99} definition is far too broad. It includes air, water, food, and so on, too, so it fails on the second requirement.
We also can’t define a drug as an illegal substance that affects mind or body in some way. This definition might cover more or less the right set of substances, but it does not meet requirement 3. It does not explain why the line belongs where it is. After all, part of the point of trying to define “drug” in the first place might well be to decide which substances should be legal and which should not! Defining a drug as an illegal substance short-circuits this project. (Technically, it commits the fallacy of begging the question.)
Try this:
A “drug” is a substance used primarily to alter our state of mind in some specific way.
Heroin, cocaine, and marijuana obviously count. Food, air, and water don’t—because even though they have effects on the mind, the effects are not specific and are not the primary reason why we eat, breathe, and drink. Unclear cases we then approach with the question: is the primary effect specific and on the mind? Perception-distorting and mood-altering effects do seem to be the chief concern in current moral debates about drugs, so arguably this definition captures the kind of distinction people really want to make.
Should we add that drugs are addictive? Maybe not. Some substances are addictive but not drugs—certain foods, perhaps. And what if a substance that “alter[s] our state of mind in some specific way” turns out to be nonaddictive (as some people have claimed about marijuana, for example)? Is it therefore not a drug? Maybe addiction defines “drug abuse,” but not “drug” as such.
Definitions help us to organize our thoughts, group like things with like, and pick out key similarities and differences. Sometimes, after words are clearly defined, people may even discover that they do not really disagree about an issue at all.
{100} By themselves, though, definitions seldom settle difficult questions. We seek to define “drug,” for example, partly to decide what sort of stance to take toward certain substances. But such a definition cannot answer this question by itself. Under the proposed definition, coffee is a drug. Caffeine certainly alters the state of the mind in specific ways. It is even addictive. But does it follow that coffee should be banned? No, because the effect is mild and socially positive for many people. Some attempt to weigh benefits against harms is necessary before we can draw any conclusions.
Marijuana is a drug under the proposed definition. Should it be banned? Just as with coffee, more argument is necessary. Some people claim that marijuana has only mild and socially positive effects too. Supposing they’re right, you could argue that marijuana shouldn’t be banned even though it is a drug (like coffee). Others argue that it has far worse effects and tends to be a “gateway” to harder drugs besides. If they’re right, you could argue for banning marijuana whether it is a drug or not.
Or perhaps marijuana is most akin to certain antidepressants and stimulants—medicines that (take note) also turn out to be drugs on the proposed definition, but call not for bans but for control.
Alcohol, meanwhile, is a drug under the proposed definition. In fact, it is the most widely used drug of all. Its harms are enormous, including kidney disease, birth defects, half of all traffic deaths, and more. Should it be limited or banned? Maybe—although there are counterarguments too. Once again, though, this question is not settled by the determination that alcohol is a drug. Here the effects make the difference.
In short, definitions contribute to clarity, but seldom do they make arguments all by themselves. Clarify your terms—know exactly what questions you’re asking—but don’t expect that clarity alone will answer them.
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