OWL at Purdue Logo

This page is brought to you by the OWL at Purdue (https://owl.english.purdue.edu/). When printing this page, you must include the entire legal notice at bottom.

Contributors:Stacy Weida, Karl Stolley.
Summary:

These OWL resources will help you develop and refine the arguments in your writing.

Developing Strong Thesis Statements

The thesis statement or main claim must be debatable

An argumentative or persuasive piece of writing must begin with a debatable thesis or claim. In other words, the thesis must be something that people could reasonably have differing opinions on. If your thesis is something that is generally agreed upon or accepted as fact then there is no reason to try to persuade people.

Example of a non-debatable thesis statement:

Pollution is bad for the environment.

This thesis statement is not debatable. First, the word pollution means that something is bad or negative in some way. Further, all studies agree that pollution is a problem; they simply disagree on the impact it will have or the scope of the problem. No one could reasonably argue that pollution is good.

Example of a debatable thesis statement:

At least 25 percent of the federal budget should be spent on limiting pollution.

This is an example of a debatable thesis because reasonable people could disagree with it. Some people might think that this is how we should spend the nation's money. Others might feel that we should be spending more money on education. Still others could argue that corporations, not the government, should be paying to limit pollution.

Another example of a debatable thesis statement:

America's anti-pollution efforts should focus on privately owned cars.

In this example there is also room for disagreement between rational individuals. Some citizens might think focusing on recycling programs rather than private automobiles is the most effective strategy.

The thesis needs to be narrow

Although the scope of your paper might seem overwhelming at the start, generally the narrower the thesis the more effective your argument will be. Your thesis or claim must be supported by evidence. The broader your claim is, the more evidence you will need to convince readers that your position is right.

Example of a thesis that is too broad:

Drug use is detrimental to society.

There are several reasons this statement is too broad to argue. First, what is included in the category "drugs"? Is the author talking about illegal drug use, recreational drug use (which might include alcohol and cigarettes), or all uses of medication in general? Second, in what ways are drugs detrimental? Is drug use causing deaths (and is the author equating deaths from overdoses and deaths from drug related violence)? Is drug use changing the moral climate or causing the economy to decline? Finally, what does the author mean by "society"? Is the author referring only to America or to the global population? Does the author make any distinction between the effects on children and adults? There are just too many questions that the claim leaves open. The author could not cover all of the topics listed above, yet the generality of the claim leaves all of these possibilities open to debate.

Example of a narrow or focused thesis:

Illegal drug use is detrimental because it encourages gang violence.

In this example the topic of drugs has been narrowed down to illegal drugs and the detriment has been narrowed down to gang violence. This is a much more manageable topic.

We could narrow each debatable thesis from the previous examples in the following way:

Narrowed debatable thesis 1:

At least 25 percent of the federal budget should be spent on helping upgrade business to clean technologies, researching renewable energy sources, and planting more trees in order to control or eliminate pollution.

This thesis narrows the scope of the argument by specifying not just the amount of money used but also how the money could actually help to control pollution.

Narrowed debatable thesis 2:

America's anti-pollution efforts should focus on privately owned cars because it would allow most citizens to contribute to national efforts and care about the outcome.

This thesis narrows the scope of the argument by specifying not just what the focus of a national anti-pollution campaign should be but also why this is the appropriate focus.

Qualifiers such as "typically," "generally," "usually," or "on average" also help to limit the scope of your claim by allowing for the almost inevitable exception to the rule.

Types of claims

Claims typically fall into one of four categories. Thinking about how you want to approach your topic, in other words what type of claim you want to make, is one way to focus your thesis on one particular aspect of your broader topic.

Claims of fact or definition: These claims argue about what the definition of something is or whether something is a settled fact. Example:

What some people refer to as global warming is actually nothing more than normal, long-term cycles of climate change.

Claims of cause and effect: These claims argue that one person, thing, or event caused another thing or event to occur. Example:

The popularity of SUV's in America has caused pollution to increase.

Claims about value: These are claims made of what something is worth, whether we value it or not, how we would rate or categorize something. Example:

Global warming is the most pressing challenge facing the world today.

Claims about solutions or policies: These are claims that argue for or against a certain solution or policy approach to a problem. Example:

Instead of drilling for oil in Alaska we should be focusing on ways to reduce oil consumption, such as researching renewable energy sources.

Which type of claim is right for your argument? Which type of thesis or claim you use for your argument will depend on your position and knowledge of the topic, your audience, and the context of your paper. You might want to think about where you imagine your audience to be on this topic and pinpoint where you think the biggest difference in viewpoints might be. Even if you start with one type of claim you probably will be using several within the paper. Regardless of the type of claim you choose to utilize it is key to identify the controversy or debate you are addressing and to define your position early on in the paper.

Contributors:Stacy Weida, Karl Stolley.
Summary:

These OWL resources will help you develop and refine the arguments in your writing.

Using Research and Evidence

What type of evidence should I use?

There are two types of evidence.

First hand research is research you have conducted yourself such as interviews, experiments, surveys, or personal experience and anecdotes.

Second hand research is research you are getting from various texts that has been supplied and compiled by others such as books, periodicals, and Web sites.

Regardless of what type of sources you use, they must be credible. In other words, your sources must be reliable, accurate, and trustworthy.

How do I know if a source is credible?

You can ask the following questions to determine if a source is credible.

Who is the author? Credible sources are written by authors respected in their fields of study. Responsible, credible authors will cite their sources so that you can check the accuracy of and support for what they've written. (This is also a good way to find more sources for your own research.)

How recent is the source? The choice to seek recent sources depends on your topic. While sources on the American Civil War may be decades old and still contain accurate information, sources on information technologies, or other areas that are experiencing rapid changes, need to be much more current.

What is the author's purpose? When deciding which sources to use, you should take the purpose or point of view of the author into consideration. Is the author presenting a neutral, objective view of a topic? Or is the author advocating one specific view of a topic? Who is funding the research or writing of this source? A source written from a particular point of view may be credible; however, you need to be careful that your sources don't limit your coverage of a topic to one side of a debate.

What type of sources does your audience value? If you are writing for a professional or academic audience, they may value peer-reviewed journals as the most credible sources of information. If you are writing for a group of residents in your hometown, they might be more comfortable with mainstream sources, such as Time or Newsweek. A younger audience may be more accepting of information found on the Internet than an older audience might be.

Be especially careful when evaluating Internet sources! Never use Web sites where an author cannot be determined, unless the site is associated with a reputable institution such as a respected university, a credible media outlet, government program or department, or well-known non-governmental organizations. Beware of using sites like Wikipedia, which are collaboratively developed by users. Because anyone can add or change content, the validity of information on such sites may not meet the standards for academic research.

Contributors:Stacy Weida, Karl Stolley.
Summary:

These OWL resources will help you develop and refine the arguments in your writing.

Organizing Your Argument

How can I effectively present my argument?

Use an organizational structure that arranges the argument in a way that will make sense to the reader. The Toulmin Method of logic is a common and easy to use formula for organizing an argument.

The basic format for the Toulmin Method is as follows.

Claim: The overall thesis the writer will argue for.

Data: Evidence gathered to support the claim.

Warrant (also referred to as a bridge): Explanation of why or how the data supports the claim, the underlying assumption that connects your data to your claim.

Backing (also referred to as the foundation): Additional logic or reasoning that may be necessary to support the warrant.

Counterclaim: A claim that negates or disagrees with the thesis/claim.

Rebuttal: Evidence that negates or disagrees with the counterclaim.

Including a well-thought-out warrant or bridge is essential to writing a good argumentative essay or paper. If you present data to your audience without explaining how it supports your thesis your readers may not make a connection between the two or they may draw different conclusions.

Don't avoid the opposing side of an argument. Instead, include the opposing side as a counterclaim. Find out what the other side is saying and respond to it within your own argument. This is important so that the audience is not swayed by weak, but unrefuted, arguments. Including counterclaims allows you to find common ground with more of your readers. It also makes you look more credible because you appear to be knowledgeable about the entirety of the debate rather than just being biased or uniformed. You may want to include several counterclaims to show that you have thoroughly researched the topic.

Example:

Claim: Hybrid cars are an effective strategy to fight pollution.
Data1: Driving a private car is a typical citizen's most air polluting activity.
Warrant 1: Because cars are the largest source of private, as opposed to industry produced, air pollution switching to hybrid cars should have an impact on fighting pollution.
Data 2: Each vehicle produced is going to stay on the road for roughly 12 to 15 years.
Warrant 2: Cars generally have a long lifespan, meaning that a decision to switch to a hybrid car will make a long-term impact on pollution levels.
Data 3: Hybrid cars combine a gasoline engine with a battery-powered electric motor.
Warrant 3: This combination of technologies means that less pollution is produced. According to ineedtoknow.org "the hybrid engine of the Prius, made by Toyota, produces 90 percent fewer harmful emissions than a comparable gasoline engine."
Counterclaim: Instead of focusing on cars, which still encourages a culture of driving even if it cuts down on pollution, the nation should focus on building and encouraging use of mass transit systems.
Rebuttal: While mass transit is an environmentally sound idea that should be encouraged, it is not feasible in many rural and suburban areas, or for people who must commute to work; thus hybrid cars are a better solution for much of the nation's population.
Contributors:Stacy Weida, Karl Stolley.
Summary:

These OWL resources will help you develop and refine the arguments in your writing.

Using Rhetorical Strategies for Persuasion

There are three types of rhetorical appeals, or persuasive strategies, used in arguments to support claims and respond to opposing arguments. A good argument will generally use a combination of all three appeals to make its case.

Logos

Logos or the appeal to reason relies on logic or reason. Logos often depends on the use of inductive or deductive reasoning.

Inductive reasoning takes a specific representative case or facts and then draws generalizations or conclusions from them. Inductive reasoning must be based on a sufficient amount of reliable evidence. In other words, the facts you draw on must fairly represent the larger situation or population. Example:

Fair trade agreements have raised the quality of life for coffee producers, so fair trade agreements could be used to help other farmers as well.

In this example the specific case of fair trade agreements with coffee producers is being used as the starting point for the claim. Because these agreements have worked the author concludes that it could work for other farmers as well.

Deductive reasoning begins with a generalization and then applies it to a specific case. The generalization you start with must have been based on a sufficient amount of reliable evidence.Example:

Genetically modified seeds have caused poverty, hunger, and a decline in bio-diversity everywhere they have been introduced, so there is no reason the same thing will not occur when genetically modified corn seeds are introduced in Mexico.

In this example the author starts with a large claim, that genetically modified seeds have been problematic everywhere, and from this draws the more localized or specific conclusion that Mexico will be affected in the same way.

Avoid Logical Fallacies

These are some common errors in reasoning that will undermine the logic of your argument. Also, watch out for these slips in other people's arguments.

Slippery slope: This is a conclusion based on the premise that if A happens, then eventually through a series of small steps, through B, C,..., X, Y, Z will happen, too, basically equating A and Z. So, if we don't want Z to occur A must not be allowed to occur either. Example:

If we ban Hummers because they are bad for the environment eventually the government will ban all cars, so we should not ban Hummers.

In this example the author is equating banning Hummers with banning all cars, which is not the same thing.

Hasty Generalization: This is a conclusion based on insufficient or biased evidence. In other words, you are rushing to a conclusion before you have all the relevant facts. Example:

Even though it's only the first day, I can tell this is going to be a boring course.

In this example the author is basing their evaluation of the entire course on only one class, and on the first day which is notoriously boring and full of housekeeping tasks for most courses. To make a fair and reasonable evaluation the author must attend several classes, and possibly even examine the textbook, talk to the professor, or talk to others who have previously finished the course in order to have sufficient evidence to base a conclusion on.

Post hoc ergo propter hoc: This is a conclusion that assumes that if 'A' occurred after 'B' then 'B' must have caused 'A.' Example:

I drank bottled water and now I am sick, so the water must have made me sick.

In this example the author assumes that if one event chronologically follows another the first event must have caused the second. But the illness could have been caused by the burrito the night before, a flu bug that had been working on the body for days, or a chemical spill across campus. There is no reason, without more evidence, to assume the water caused the person to be sick.

Genetic Fallacy: A conclusion is based on an argument that the origins of a person, idea, institute, or theory determine its character, nature, or worth. Example:

The Volkswagen Beetle is an evil car because it was originally designed by Hitler's army.

In this example the author is equating the character of a car with the character of the people who built the car.

Begging the Claim: The conclusion that the writer should prove is validated within the claim. Example:

Filthy and polluting coal should be banned.

Arguing that coal pollutes the earth and thus should be banned would be logical. But the very conclusion that should be proved, that coal causes enough pollution to warrant banning its use, is already assumed in the claim by referring to it as "filthy and polluting."

Circular Argument: This restates the argument rather than actually proving it. Example:

George Bush is a good communicator because he speaks effectively.

In this example the conclusion that Bush is a "good communicator" and the evidence used to prove it "he speaks effectively" are basically the same idea. Specific evidence such as using everyday language, breaking down complex problems, or illustrating his points with humorous stories would be needed to prove either half of the sentence.

Either/or: This is a conclusion that oversimplifies the argument by reducing it to only two sides or choices. Example:

We can either stop using cars or destroy the earth.

In this example where two choices are presented as the only options, yet the author ignores a range of choices in between such as developing cleaner technology, car sharing systems for necessities and emergencies, or better community planning to discourage daily driving.

Ad hominem: This is an attack on the character of a person rather than their opinions or arguments. Example:

Green Peace's strategies aren't effective because they are all dirty, lazy hippies.

In this example the author doesn't even name particular strategies Green Peace has suggested, much less evaluate those strategies on their merits. Instead, the author attacks the characters of the individuals in the group.

Ad populum: This is an emotional appeal that speaks to positive (such as patriotism, religion, democracy) or negative (such as terrorism or fascism) concepts rather than the real issue at hand. Example:

If you were a true American you would support the rights of people to choose whatever vehicle they want.

In this example the author equates being a "true American," a concept that people want to be associated with, particularly in a time of war, with allowing people to buy any vehicle they want even though there is no inherent connection between the two.

Red Herring: This is a diversionary tactic that avoids the key issues, often by avoiding opposing arguments rather than addressing them. Example:

The level of mercury in seafood may be unsafe, but what will fishers do to support their families.

In this example the author switches the discussion away from the safety of the food and talks instead about an economic issue, the livelihood of those catching fish. While one issue may effect the other, it does not mean we should ignore possible safety issues because of possible economic consequences to a few individuals.

Ethos

Ethos or the ethical appeal is based on the character, credibility, or reliability of the writer. There are many ways to establish good character and credibility as an author:

Pathos

Pathos, or emotional appeal, appeals to an audience's needs, values, and emotional sensibilities.

Argument emphasizes reason, but used properly there is often a place for emotion as well. Emotional appeals can use sources such as interviews and individual stories to paint a more legitimate and moving picture of reality or illuminate the truth. For example, telling the story of a single child who has been abused may make for a more persuasive argument than simply the number of children abused each year because it would give a human face to the numbers.

Only use an emotional appeal if it truly supports the claim you are making, not as a way to distract from the real issues of debate. An argument should never use emotion to misrepresent the topic or frighten people.