A thesis is a single sentence that expresses the controlling idea of a written work. The thesis is the main idea of the work, the core of the essay. It drives the goals and structure of the work. Note that there is a controlling idea for each essay, and for each paragraph in an essay. Think of the thesis as the anchor for the writing project as a whole: both for the writer, putting his or her ideas, arguments, and support down on paper, and for the readers of that writing.
Thesis statement: Police need advanced weapons and tactics to combat modern criminals and terrorists.
Here's another option for the essay's argument:
Thesis statement: After 9/11 and the Homeland Security Act, militarization of police has been a government priority, although it has nothing to do with actual police work.
Here's another option:
Thesis statement: The militarization of police is a big step backwards for America, and an example of fear of the "wrong" parts of our society.
Each of these three thesis statements are only related through their shared topic. Some might be directly opposed to others. Within one topic, multiple thesis statements can be identified.
Once you've selected a topic and a thesis, you must support the thesis by developing your ideas effectively. This is accomplished through a process of articulating your ideas and supporting them with evidence and reasoning throughout the essay. It includes generating claims and main ideas, as well as finding and building support for them.
When writers refer to development, they're not not only referring to development of the essay as a whole, because this process also takes place at the paragraph level. Paragraphs function like mini-essays: each of them contains their own main ideas, topic sentences, and support.
To effectively state and support a thesis, most essays must also promote related points — points that, together, prove or support the thesis. In composition, these are called main ideas and claims. A main idea is a primary point or concept that drives the organization of an essay. Each main idea in an essay should contribute to, or support, the thesis statement in some way. A claim is a type of main idea in which the writer makes a statement that must be defended. A claim is an assertion made by the writer.
The thesis statement is the primary claim of the essay — the object of all of the essay's support, ideas, and evidence. The main idea, when coupled with a claim, is usually the controlling idea of the paragraph. When working on the level of the paragraph, the main idea and the controlling idea are synonymous.
If it was sufficient to simply state claims and thesis statements, writing would be much easier. However, they must also be supported, usually with evidence. Evidence, one of the most common forms of support, is proof of the validity of a claim or claims. It can include the following:
Even though some writers use the words "evidence" and "support" interchangeably, support is a broader term that refers to any evidence, logic, or other technique (e.g., clarification, expansion of ideas) that bolsters an essay's claims. The purpose of support isn't solely to prove that a thesis is true, but also to explain or substantiate the essay's main ideas.
Because essays consist of paragraphs that use claims, evidence, and other forms of support to back up the thesis, it's important to consider paragraphs in order to understand the essay as a whole. Paragraphs are like miniature essays that include a topic sentence (i.e., the sentence that states the paragraph's thesis) and support — usually evidence for the topic sentence.
Following are three paragraphs from the same essay which demonstrate how the overall thesis is introduced, developed, and supported. In this first paragraph, see if you can identify the topic sentence and the different kinds of support that are provided for it.
The global struggles today show that a new definition for patriotism is needed — a global definition. Patriotism must encompass compassion for our fellow human beings, regardless of where they live. In the words of James Bryce, a British jurist, historian, and statesman, "Our country is not the only thing to which we owe our allegiance. It is also owed to justice and humanity" (Barnaby 12). Patriotism is not the supreme ideal that many politicians claim that it is, and it isn't merely a source of evil in the world. Its true definition must incorporate both of these ideas. Patriotism should not only mean love of one's country, and it should not require suspicion of foreigners. A modern definition must include compassion and ethics. The world needs patriotism to mean love for all people, regardless of their nationality.
Although a number of ideas are presented, the thesis is likely contained in the second sentence: "Patriotism must encompass compassion for our fellow human beings, regardless of where they live." Don't worry if you identified another part of the paragraph as the thesis. This paragraph doesn't just introduce the essay's thesis, it also presents some of the other main ideas.
EXAMPLEThe sentence that includes the quotation that refers to allegiance to other ideals besides "country" will come up again, as will a discussion of compassion and ethics. Each of these expansions will work in one way or another to support the thesis.
Now, read this paragraph, taken from a later point in the same essay.
To see evidence that in many ways, love does indeed stop at the borders of our country, all you have to do is listen to the closing words of most presidential speeches. George W. Bush ended the speech in which he accepted the Republican Party's nomination for president with the traditional "God bless America." These three words indicate that it is acceptable to ask God to favor our nation over those of our neighbors. Why don't we hear "God bless the world," "God bless everyone," or "God bless us all" more often? By neglecting to pray for others, we are saying that we do not care about them, whether we mean it or not.
The phrasing of the first sentence clearly identifies this paragraph's main idea, doesn't it? Although it's not always indicated this clearly, the topic sentence is often the first sentence in a paragraph, and the support for it is often everything else in the paragraph. Support for the claim that love stops at the borders is provided by the reference to the Bush acceptance speech, as well as the writer's interpretation of "God bless America" and his or her statements about the assumptions we make as a country.
In the following paragraph, a different type of evidence is offered. See if you can recognize the topic sentence and its support.
Though our situation today is not so drastic, it is important to remember that patriotic injustices are not a thing of the past, or of other, failed governments. While the Holocaust was in progress, over 80,000 Japanese-Americans were legally imprisoned in internment camps in America, though they were only guilty of sharing a race with a country with which the U.S. was at war. Today, the Patriot Act enables federal investigators to disregard civil rights to pursue terrorists by monitoring telephone and electronic communications of people who are not suspected of having committed crimes. The presence of the right "keywords" in your email messages allows investigators to violate your right to privacy and read, record and archive your personal correspondence.
Again, the first sentence of this paragraph is the topic sentence. It makes the claim that patriotic injustice is not just a thing of the past, or of other countries. By means of the first example — the U.S. government's imprisonment of Japanese-Americans while fighting a war against Nazi Germany — this paragraph makes clear the writer's assertion that America has performed terrible acts in the name of patriotism. Next, a more current example is presented: the reference to the Patriot Act and the power it gives government officials to spy on U.S. citizens.
Whether or not you agree with the writer's assertions or reasoning, this paragraph supports its topic sentence, as well as the essay's thesis.
Source: Adapted from Sophia Instructor Gavin McCall