CARS Lesson 6  —  What is an argument?
Claims backed by reason and evidence

Some arguments aim to convince, others to inform, and other arguments are an invitation to learn about a topic or an idea. Some arguments are looking for common ground. Some arguments make proposals for action. Every CARS passage is an argument. In choosing the particular CARS passage and designing the questions for it, the test-writers have created a kind of game you play well by giving the passage a close reading and then demonstrating in the questions that you understood how the argument justified its claims and whether the argument is persuasive.

Learning the various ways arguments are traditionally structured will make you stronger in CARS. Structure is central to communication in essay writing. The structure represents the map of the world each passage has invited you to explore. Understanding the structure of an argument is a big step to understanding what the author set out to accomplish in writing the passage.

CARS passages don't conform to textbook rules. Nevertheless, once you start looking, you will find the following traditional ways to structure arguments within many MCAT passages. The three most influential ways to structure argument in the humanities and social sciences are classical, Rogerian and Toulmin.


Aristotle's Rhetoric is an ancient Greek treatise dating from the 4th century BCE. In these lectures, Aristotle developed the basis of a system that has influenced argumentation from ancient through modern times. The Rhetoric is regarded as the most important single work on persuasion ever written.

Why are we taking the time to review an ancient philosopher's ideas when we have all that organic chemistry to review? Like the other styles of argument we discuss in this lesson, we're looking at Aristotle's Rhetoric because it will give you some perspectives that make the strategies the authors employ in CARS passages more transparent. Still, we will try to be concise.

Rhetorical Appeals

To understand how classical argument works, you start with the three means of persuasion that the essay writer relies on: those grounded in credibility (ethos), in the emotions and psychology of the audience (pathos), and in patterns of reasoning (logos).

  • Ethos

    An appeal to ethos is an appeal to credibility. How does the author present themselves to the audience? Authors build credibility by citing professional sources, and by sharing credentials or background. Authors also build credibility by qualifying claims reasonably and presenting evidence in full. They also acknowledge important objections to their position.

  • Pathos

    An appeal to pathos is an appeal to emotion. How does the work evoke feelings? Authors may achieve pathos in an argument through vivid imagery, story-telling or an impassioned style of writing.

  • Logos

    An appeal to logos is an appeal to logic. It persuades the audience through reason and evidence. Logos develops through rational premises and conclusions in logically sequenced arguments or it involves inferences backed by data and statistics.


There are six components to the classical argument, usually in the following order:

  • Introduction (Exordium)

    The author captures the attention of the audience with the exordium. The exordium gains the interest of the reader, situates the argument, and sets the stylistic tone.

  • Background (Narratio)

    The narratio provides a brief account of the circumstances, conditions, or events the audience needs to be made aware of. What is the current situation? What created the situation? Who is affected by this? Who is researching this?

  • Proposition (Partitio)

    Partitio presents the main idea or thesis. Partitio transitions from the narratio and outlines the reasoning that will follow in confirmatio to support the thesis.

  • Evidence and Proof (Confirmatio)

    The confirmatio is the main body of the argument. Logic and evidence based reasoning is presented to support the claims and subclaims of the thesis. The appeal to logos is emphasized in confirmatio.

  • Counterarguments (Refutatio)

    This section answers counterarguments to the thesis. With refutatio the author demonstrates that they really have considered the issue thoroughly and have reached the only reasonable conclusion.

  • Conclusion (Peroratio)

    The argument ends with a summary of the most important points. Peroratio will often also include appeals to values and emotions to encourage the reader to agree with the author's thesis.


Influenced by the humanistic psychology of Carl Rogers, the Rogerian method of argument is based on empathizing with others and seeking mutual understanding, while avoiding the unproductive effects of polarization. Rogerian argument carefully acknowledges and seeks to understand opposing viewpoints, rather than aiming to defeat or dismiss them.

In the 1970 textbook Rhetoric: Discovery and Change, the University of Michigan professors Richard E. Young, Alton L. Becker, and Kenneth L. Pike developed an influential structure for argumentation that is now known as Rogerian argument.

  • Introduction

    The argument begins with a description of the problem in terms that are rich enough for opponents to identify with. The introduction is an invitation for everyone to see the benefits of positive change and want to work to solve the same problem.

  • Summary of opposing views

    In as fair and neutral a way as possible, the views of opposing positions are stated in a way that demonstrates true consideration of their merits.

  • Statement of validity

    The writer describes the contexts in which the opposing views may be justified. There may be conditions under which the writer may share the views.

  • Writer's position

    The writer states their own position and the circumstances or conditions in which their opinion would be valid.

  • Statement of benefits

    Appeal is made to the interest of opponents in adopting the writer's position.

It is extremely valuable in CARS passages to recognize when an author shifts into a Rogerian mode. There may only be a few subtle indications that the author is presenting a position they actually don't fully agree with. Sometimes you have to see the entire structure of the argument to understand that the author doesn't actually share the position. In Rogerian argument, different points of view may be tried on for a while like clothes to see if they fit. A formation within Rogerian argument can sometimes move from thesis (maybe it's this way) to antithesis (oh wait, maybe it's that way instead) then on to synthesis (here's what I really think). In a wrong multiple choice answer, MCAT question-writers love to see if you will attribute a point of view to the author that the author actually argues against later in the passage. Speed readers can get punished in questions like this. Sometimes the main idea will depend on the whole structure of the argument, not a particular point of view explored within a part of it.


Developed by the British philosopher Stephen Toulmin and published in his 1958 book The Uses of Argumentation, the Toulmin model of argument is not only for analyzing arguments but also for constructing them. If you can internalize this framework so that it becomes natural and intuitive, you will become both a stronger reader and writer. On the CARS section of the MCAT, you will find you are predicting many of the questions before you get to them.

The starting point for the Toulmin framework is that for an argument to succeed, it needs to provide rational justification for the claims it makes. Such an argument can stand up to a critical reading. Toulmin proposed six interrelated components for analyzing arguments to see if they provide rational justification for belief.

  • Claim

    This is the statement of fact or opinion the author is asking their audience to believe to be true. What's the author's position? What's their point? The aim of an argument is to establish a claim as a justified belief. In some arguments the claim takes the form of a thesis statement.

  • Evidence

    The evidence (grounds) are the facts or rationale that the author will appeal to as the basis for the claim. The evidence makes the case for the claim.

  • Warrant

    The warrant establishes the connection between the claim and the facts supporting it. The warrant is the underlying link between the evidence and the claim. If the warrant is strong, the claim is warranted by the support provided.

  • Backing

    Backing refers to additional support of the warrant. It tells the reader why the warrant is a rational one. The warrant asserts that the evidence is sufficient to obtain assent to the claim, but in many cases, the warrant is implied. Backing may be a specific example that justifies the warrant.

  • Rebuttal

    Rebuttal acknowledges another valid view of the situation. This is where the author addresses potential objections to the claim.

  • Qualifier

    A qualifier shows that a claim may not be true in all circumstances. Words like “presumably,” “some,” and “many” help the author communicate they know there are instances where your claim may not be correct. A qualifier adds nuance and specificity to the claim, helping to counter rebuttals.

The Toulmin model is a heuristic that helps you evaluate the substance and quality of an argument. One of the preoccupations with CARS, for example, is the concept of the main idea of the passage. In the Toulmin model, this is the argument's claim along with qualifiers and exceptions.

Additionally, reading critically means evaluating the effectiveness of evidence. The Toulmin model gives us a framework for evaluating evidence. You interrogate the evidence for its warrant. Sometimes the warrant will be a value judgement. If you restate the value being invoked as clearly as possible you might see the author waving their hands to distract you from the weakness of their argument. When you spot a weakness in the passage author's argument, you know a question is coming.

Putting it all together

Please don't take this lesson to mean that every CARS passage exactly conforms to one of the above structures and it is a productive exercise to figure out which one it is. That would be distracting! Most passages actually possess aspects of all three - classical, Rogerian and Toulmin. The purpose of learning about the structure of argument is to be more sophisticated in critical reading. Understanding traditional structures of argumentation helps you understand the challenges the author is trying to overcome in effective communication, and it helps you understand the point of view the test-writers at AAMC. This is the perspective they bring to writing the questions.

When you are reading critically, you are asking questions like - What is the purpose of this argument? What does it hope to achieve? Does this argument appeal to me? If it does appeal, then what strategies did the author employ? Why does it succeed? What kinds of appeals does it make? To ethos, pathos, or logos? Does it anticipate and give respectful hearing to counter-arguments? What claims does it make? Are they warranted by evidence? How is the argument structured?

Let's practice

Students often make a mistake in MCAT preparation assuming that because they complete a passage and review the answers carefully, they are done with that passage forever. On the contrary, you can learn a great deal from the passages and questions you have already done. You are starting to know those passages pretty well, but think of how well the person at AAMC knew the passage when they wrote the questions. Try to reach that state, where you can see a passage all the way to the bottom. Try to get to that place with a few of the passages we completed in earlier modules.

At this stage we have completed all passages in CARS Question Pack 1 as well as the first seven passages of CARS Question Pack 2. Choose three or four passages you have already done and take some time to read those again carefully. Study them in the light of the content of this lesson, structures of argumentation. Study a few passages in the light of the classical, Rogerian, and Toulmin models of argument. Next, imagine you were the question-writer and then go to the questions and review what the actual question writer came up with.

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