2.2 Explaining and analyzing the line of reasoning of an argument

8 min readdecember 30, 2022

Minna Chow

Minna Chow

AP Research 🔍

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In this guide, we'll cover how to explain the line of reasoning for an argument. This is a concept that was first introduced in AP Seminar, but continues to be relevant for AP Research. Not only will you need to understand the line of reasoning for other people's arguments, you'll also need to understand your own line of reasoning in your paper. We're also gonna be talking about
Definitions and Information come from page 20 of the AP Research CED.
So, let's recap! What is a line of reasoning?

Line of Reasoning

A line of reasoning is defined by College Board as one or more claims justified through evidence (for an argument.)
Sometimes, the line of reasoning consists of only one piece of evidence and reasoning.
For a silly example, suppose you were arguing with a friend about if pineapple belongs on pizza. You argue yes (go with me) and your claim is that pineapple belongs on pizza because it's delicious. You know because you've had pineapple on pizza before.
In this example...
  • Your argument is that pineapple belongs on pizza.
  • Your claim is that pineapple on pizza tastes good.
  • Your evidence is that you've eaten pineapple on pizza before.
In this case, your line of reasoning is one claim-evidence pair long.
However, with more complicated arguments (like the thesis statement of a whole paper, or a section of a paper) the line of reasoning will be much longer.

What does a Line of Reasoning Look Like?

Not every line of reasoning is organized in the same way. They'll differ based on the purpose of the argument.
  • For example, if your argument is meant to show causality, you might start by defining the issue, then claiming A causes B, then give your reasons, and at the end explain why they matter.
  • However, if you want to propose a solution, you might present a shortened version of a causality essay so you have space for evidence that supports your solution.
So, how can you tell what the line of reasoning is? Start by looking at the argument's purpose! Ask yourself, what is this argument trying to do? Once you have the answer, look at how the paper attempts to accomplish its goal to establish causation or propose a solution or create a call to action... It will generally do this through a series of claims with (hopefully) evidence attached to said claims; that series is your line of reasoning.
Research Tip: Art can also have lines of reasoning. According to College Board, Scholars analyze artistic works in terms of internal coherence and alignment of the purposes, goals, and methods of inquiry, all of what we look for when looking at line of reasoning. (Admittedly, it's much easier to do this with a written work like a novel than a painting.)
It might help to understand what some types of reasoning are.

Types of Reasoning

The College Board wants you to at least be aware of two types of reasoning: Inductive and Deductive Reasoning. Inductive reasoning uses specific observations and/or data points to identify trends, make generalizations, and draw conclusions. You can think of it as "bottom up" reasoning; it takes examples to prove the rule. For example, in the pineapple on pizza argument, the specific fact that "I think pineapple on pizza is delicious" is used to come to the broad conclusion that "pineapple belongs on pizza."
With inductive reasoning, you want to watch out that your specific observations do lead to your larger conclusion. In my pineapple on pizza argument, you can easily argue against it by saying that just because I like pineapple on pizza doesn’t mean it belongs on pizza.
Deductive reasoning uses broad facts or generalizations to generate additional, more specific conclusions about a phenomenon. This is "top down" reasoning; it uses facts that are assumed to be true to come to specifics.
Let's look at an example from pop fiction! Famously, Arthur Conan Doyle's Sherlock Holmes was able to use deductive reasoning to deduce information about people. In the Red-Headed League, he deduces that his client has done a lot of writing because his sleeve cuffs are shiny from rubbing on a desk. This is an example of deductive reasoning because Holmes is taking a generalization (a shiny sleeve cuff indicates that someone writes often) to generate specific conclusions (my client has done a lot of writing recently.)
How could we make this a case of inductive reasoning?
Imagine if Holmes's client says that he's done a lot of writing recently. Later, Holmes observes that his client has a shiny sleeve cuff. After seeing many writers with shiny sleeve cuffs, Holmes concludes that shiny sleeve cuffs are an indication that someone's a writer.

GIF from Giphy.com

With deductive reasoning, you want to watch out that the assumed facts are actually true (or as true as they can be.) If it can be proven that shiny sleeve cuffs don't indicate that someone writes often, or could indicate something different, then Holmes's specific deduction about his client wouldn't be true.
Research Tip: You don't need to know the types of reasoning inside and out, and you won't be directly tested on them. However, they are important to know in order for you to understand how you're structuring your essay. They can also help you understand the arguments of others.

Validity of an Argument

It's important to understand the line of reasoning of an argument because once you do, you can tell if the argument is valid or not. People generally have a sense for lines of reasoning. We can tell if an argument isn't quite right or if there seems to be a hole in the logic. However, that sense isn't always well developed, and can be confused. A writer or speaker can deliver a message so dazzlingly well that they can conceal logical contradictions, errors, and just plain bad argumentation.
How do they do this? Have you ever heard the saying, "it's not what you say but how you say it?" Writers have a variety of rhetorical strategies to get their message across. Let's cover them briefly here.

Rhetorical Strategies

Here are some examples of rhetorical strategies:
  • word choice (ex: loaded language)
  • appeal to authority/emotion/logic (ex: appealing to the audience's compassion, appealing to one's wealth and success)
  • qualifiers (words like probably, mostly, and so on; these prevent arguments from sounding too conclusive if they're actually not.)
  • fallacies like No True Scotsman (only a fake pizza lover could stand pineapple on pizza!) or Slippery Slope (if we allow pineapple to be on pizza, it will cause a chain reaction that leads to the destruction of the pizza industry!)
  • emphasis words like absolutely, necessary, conclusively, highlight, emphasize, etc
With the exception of fallacies, these strategies are not by themselves bad things. In fact, they're efficient tools to get one's message across!
Research Tip: We cover rhetorical devices and strategies in our AP Lang Guides, which you can find here.
Rhetorical devices can be a tool for "evil" when they're used to manipulate, mislead or deceive an audience. In order to tell if an argument is valid, we need to look beyond flashy rhetorical strategies and focus on the meaning of the arguments we’re presented.

Looking for Logical Alignment

In short, an argument is valid when there is logical alignment between the line of reasoning and the conclusion. This means that you as the reader can understand how the line of reasoning naturally leads to the conclusion presented. You're looking to see...
  • Does the evidence makes sense?
  • Does this evidence do what the author says it does?
  • Is this really evidence or just a very strong opinion without anything to back it up? (This happens more often than you'd think.)
Of course, it's possible not to understand an argument that is still valid. Some arguments take time to work through, and sometimes you just don’t have the background understanding needed to tackle a certain argument.
However, if you detect misalignment between the line of reasoning and the conclusion, if you don't understand how the author got from point A to point B or you feel that point A doesn't lead to point B, it's perfectly healthy to doubt the conclusion you've been given.
Research Tip: Diagramming the Line of Reasoning visually, such as making a flowchart on a sheet of paper, can help cut away the argument to its bare bones and make it easier to understand. I highly recommend making a diagram when you want to analyze the Line of Reasoning.

Acknowledgement of Complexity

Another indicator of whether or not an argument is valid is if it acknowledges complexity or not. While not a dealbreaker, it's a red flag if the argument you're reading doesn't acknowledge its context, limitations, implications, or other arguments on the same topic. What does this look like?
  • Context: Generally, papers will have an introduction and/or a place for a topic overview, where the author discusses what's already been said and done about this subject. This context doesn't have to be all-inclusive — indeed, it's almost impossible to be — but the context should be at least acknowledged.
  • Limitations: No single research project or paper can cover everything, and papers should announce where the limits of their research are.
  • Implications: Why should we care about this conclusion or solution? We'll discuss more about implications here.
  • Other arguments: Effective arguments acknowledge opposing or qualifying arguments. They can just be accepted or they can be countered (such as refuting or rebutting them.) It doesn't make an argument weaker to say that not everyone agrees with it; on the contrary, it shows that the author acknowledges the complexity of the work they're handling.

Why Does This Matter?

If you don't understand an argument's line of reasoning, it can be hard to deal with its complexity as well. If you don't understand the complexity of an argument you want to use in your paper, you might oversimplify or generalize it in your writing. This will make your final paper weaker.
In this guide, we've covered lines of reasoning and ways to analyze the big-picture claims of an argument, paper or section of a paper. In the next guide, we'll be looking specifically at how evidence can be analyzed.

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