Arguing a point is presenting your opinions on an issue as clearly and convincingly as you can.  This type of writing is frequently assigned in college courses in the humanities and social sciences.  You may want to persuade your readers to adopt your point of view, but even if they don't, you want them to acknowledge that your claim rests on solid evidence and that you have good reasons for the position you take.  Writing an argument is a frequent task outside college, too--in letters to the press or to government agencies or business organizations, in business reports, and in community service.

Groundwork:  issue and audience

If you are not assigned a topic that derives from class discussion or reading, choose an issue that is interesting for you to write about and for your readers to read about.  The issue you choose should be one that you hold an opinion on; however, you should be prepared to find out more about the issue in order to express and support an educated opinion--which might even differ from your original opinion.
        Consider, too, whom you are writing for.  Assess what your readers know, what assumptions they hold, what they need to know, how they could best accept the position you take on the issue, and what strategies will persuade them to respect or accept your views.  If you are writing for a general reader rather than for one specifically defined, remember to include any necessary background information; do not simply assume that a general reader knows a great deal more than you do.  For example, if you want to argue that all airline attendants should be financially compensated for years of passive smoking (breathing in secondhand smoke) on planes, you will need to consider carefully who your readers are.  Airline attendants, airline administrators, union leaders, tobacco company representatives, smokers, or nonsmokers will bring their own assumptions and biases to the argument.  Consider and address such biases.
        Although you might start off with an idea of your position on the issue (a working thesis), make sure that you do a great deal of information gathering.  Brainstorm or freewrite, ask others their views, perhaps conduct interviews, and definitely do research (in the library and on the Internet).  Find out what has been written on both sides of the issue you are exploring.  Make lists of the arguments you come across on each side.

Your claim, reasons, and evidence

Claim.  A thesis in an argument is the claim you make about an issue.  Your research might alert you to new ideas, sometimes leading you to modify your claim, making it less all-embracing or less extreme.  Here is how one student progressed.

    Issue:  secondhand smoke on airplanes
    Audience:  general audience
    Initial claim (working thesis):  All flight attendants who have been subjected to secondhand smoke should receive substantial financial compensation from their employers.
    Modified claim (after some brainstorming and research):  Flight attendants who suffer from diseases shown to be connected to inhaling secondhand smoke on airlines for at least five years before 1995 should have the costs of their treatment and disability covered by tobacco companies.

Reasons for your claim.  Imagine someone saying to you, "Okay, I know what position you have taken on this issue, but I don't agree with you.  Tell me your reasons for taking that position."  State your arguments in support of your claim, and tell why you think what you think.  At this point, make a rough outline of your essay:  the claim and the reasons you will give for supporting it.

    Claim:  Flight attendants who suffer from diseases shown to be connected to inhaling secondhand smoke on airlines for at least five years before 1995 should have the costs of their treatment and disability covered by tobacco companies.

    Reasons:

    1.  Tobacco companies have concealed evidence that nicotine causes cancer.
    2.  Studies show that secondhand smoke can be damaging.
    3.  Before 1995, smoking was allowed on most commercial airlines and attendants spent many hours a day inhaling smoke.

Specific evidence:  You need reasons, but reasons are not enough.  You also need to show your readers specific evidence supporting your reasons.  Imagine a reader saying, after you give one of your reasons, "Tell me more about that."  The details you provide are what will make your essay more vivid.  Add to the outline any items of concrete evidence you will include to illustrate and explain your reasoning.  Include facts, statistics, stories, examples, and testimony from experts.

Refutation of the opposition

From the list you made of the arguments opposing your view, describe the most popular or convincing ones, tell why people take those positions, and then show why their reasons are illogical, unimportant, irrelevant, false, or at least not as convincing as your own.  You could do this early in your essay, as you make your own reasons, or toward the end, but that refutation needs to be in there somewhere.  Be careful here to deal with logic and reason.  Don't resort to saying that opposing views are "immoral," "ridiculous," or "stupid."  Be respectful of your opponents' views and point out rationally where your views differ.

Methods of reasoning

As you present your arguments, pay attention to the methods you use.  Make sure that any conclusions you draw follow from the evidence you provide.  If you say that some attendants on one airline have developed cancer, it would be too sweeping a conclusion to then say that all attendants should receive financial compensation.  If you say that "because asbestos workers have received compensation, airline personnel should, too," you might be accused of not providing relevant evidence.
        If you begin your argument with generalizations and argue deductively from the generalizations, you have to be sure that the premises of your argument are valid.  If you state that "smokers take a calculated risk" and that "Ellen is a smoker," it is valid to conclude that "Ellen takes a calculated risk."  However, it is not valid to use as a premise "Smokers die from smoking-related diseases" and "therefore, Ellen will, too"; not all smokers' deaths are related to cigarettes.

Flaws in logic

The following flaws in logic can make your readers mistrust you as a writer.  Watch out for these flaws as you check your drafts.

Sweeping generalizations.  Generalizations can sometimes be so broad that they fall into stereotyping:  "All British people are stiff and formal" or "The only thing that concerns students is grades."

Hasty conclusions with inadequate support.  To convince your readers of the validity of a generalization, you need more than one personal example:  "My friend Arecelis had a terrible time in a bilingual school.  This experience shows that bilingual education has failed."

Non sequitur.  Non sequitur is Latin for "It does not follow."  This sentence is a non sequitur:  "Anna Quindlen writes so well that she would make a good teacher."  The connection between writing and teaching has not been established.

Causal fallacy.  You are guilty of causal fallacy if you assume that one event causes another when the second merely follows the first in time.  (The Latin name for this logical flaw is post hoc, ergo propter hoc:  "after this, therefore because of this.")  Example:  "The economy collapsed because a new president was elected."

Ad hominem attack:  Ad hominem (Latin for "to a person") refers to an argument that appeals to personal considerations rather than to logic or reason.  Avoid using arguments that seek to discredit an opinion through personal criticism, such as "The new curriculum should not be adopted.  The administrator who favors it doesn't even live near this college."

Circular reasoning.  In an argument that uses circular reasoning, the evidence and the conclusion restate each other, thus proving nothing:  "That rich man is smart because wealthy people are intelligent."

False dichotomy or false dilemma.  Either/or arguments reduce complex problems to two simplistic alternatives without exploring them in depth or considering other alternatives without exploring them in depth or considering other alternatives.  For example, an essay that builds its arguments on the assertion "To improve education, the Board can either hire more teachers or build more schools" presents a false dichotomy.  Those two options are not the only ways to improve education.