The parts of arguments

A lot of what we cover in this course is already familiar to you. Everyone knows what reasons, objections, and conclusions are – in a vague sort of a way. But they struggle to apply this vague understanding to more complex arguments. This course will help you systematize and generalize your commonsense understanding of arguments and critical thinking.

Argument analysis is a practical skill and it can only be mastered via practice. There isn’t a lot of theory to be covered, but we do want to be clear about the terminology that we use.

This chapter provides a quick summary of the components of arguments. More detailed discussion of the important features of each will follow in later chapters.


The word argument often refers to a heated debate. But we will not be studying that sort of argument. Instead, we are interested in arguments that are intended to show that a claim is true or false. The cases put forward by lawyers in court are of this sort.

At a minimum, an argument consists of a conclusion and at least one reason or objection. Most interesting arguments consist of many reasons and objections. This complexity makes having a visual representation of an argument’s structure very helpful. Such representations are called argument maps.

To properly evaluate an argument you need to understand the relationship between the reasons and objections and the conclusion. An argument map visually represents these relationships.

Conclusions, reasons and objections

Here’s a simple argument:

Samantha: I think John Doe will be elected President. He is currently the most popular candidate, and the most popular candidate currently will be elected.

The conclusion is “John Doe will be elected President“. Samantha provides us with a reason to believe it: “He is currently the most popular candidate, and the most popular candidate currently will be elected“. In an argument map, this very simple argument would be represented like this.

The conclusion is put at the top of the map, and the reason in a green box below it, with a green line connecting them, showing that the reason aims to support the conclusion. Let’s look at Neil’s contribution:

Neil: I’m not so sure if John Doe will be elected, I heard that he will soon be caught up in a sex scandal and someone caught up in a sex scandal will not be elected President.

Neil has provided an objection to the conclusion. Objections are represented by red boxes; they aim to weaken the conclusion. So our argument map now looks like this:


You’ll see that each claim (for example, “John Doe will soon be caught up in sex scandal“) is in a separate white box, called a claim box. Claims are the basic building blocks of arguments.

A claim states that something is the case. Claims can be true or false. Obviously, if what the claim states is in fact the case, then the claim is true; if not, then it is false.

Everything in an argument consists of claims, related to one another in a certain way. Our argument about John Doe’s election chances consists of five claims. The conclusion is a claim. The reason and objection are each made up of two claims. When claims form a reason or an objection, they are called premises.

Complex arguments

Each premise is a claim that is potentially debatable. In other words, we can attach reasons or objections to each premise and our map can continue to grow. Here, we’ve added some additional reasons and objections:

This map also shows how a claim can be both a premise and a conclusion. Claim 1A-a “John Doe is currently the most popular candidate” is a premise for the final conclusion “John Doe will be elected President”, and it is also a conclusion for Reason 2A. We will call these conclusions intermediate conclusions to help distinguish them from the final conclusion.

Claims are only premises or conclusions relative to other claims, just as a woman is only a mother relative to her children, a daughter relative to her parents, a sister relative to her siblings, and so on. In the above argument 1A- a is a conclusion relative to 2A-a, a co-premise relative to 1A- b, a disputed claim relative to 2B-a, and a premise relative to the final conclusion.


When we start assessing the quality of arguments we focus on just an individual reason and its conclusion. We will call an individual reason and its conclusion an inference as this is a handy way to refer to the individual steps in an argument. We also use it to refer to an objection and the claim it disputes, as an objection is a actually a reason for the negation of the conclusion. (E.g. The claim that “John Doe will soon be caught up in a sex scandal” is a reason to believe that “It is not the case that John Doe will be elected president.“)

In an argument map, the green and red connecting lines show the inferences or steps in the argument. Our example consists of the five inferences (you will notice that some of these share the same conclusion/disputed claim).

Argument maps enable us to isolate individual argument units. This allows us to break down the huge complexity of many arguments into more bite-sized bits that can be considered one by one.

Argument Signposting

Often authors are kind enough to signpost how their arguments fit together – what their final and intermediate conclusions are, what reasons they have for their various conclusions, etc. They do this by using words such as “therefore”, “because”, and phrases such as “hence we assess that” and “I object because”. These indications are called appropriately enough, argument signposts. Signposts help the reader locate and follow the reasoning. This is often helpful when an argument is expressed in prose, but argument maps make the structure of the reasoning clear and vivid, so there is no need to include such phrases in the map. The green lines indicating the connection between reasons and conclusions and the red lines indicating the connection between objections and disputed claims replace the argument signpost phrases.

For instance:

David is rich. There are two reasons for thinking this: firstly, he drives a sports car, and only rich people drive sports cars; and secondly, he lives in a mansion, and only rich people live in mansions.

The extended phrase “There are two reasons for thinking this: firstly… secondly…” is argument signposting. It tells the audience that there are two reasons and what they are. But the map directly shows this:

This map conveys all the information that the signposting in the original prose conveys. It is clear from the map that two reasons are being put forward to support the conclusion. So there is no need to include “There are two reasons for thinking this: firstly… secondly… “.

Here is another example:

Some people argue that the Moon landing was faked. But this is false. If the Moon landing was faked the Russians would’ve found this out, but the Russians didn’t find this out.

Here, “but this is false” is a signpost. It indicates that the arguer disagrees with a certain claim, and signals that an objection is coming. The map makes it clear that the claim is being objected to, so there’s no need to include “but this is false”:

Notice also that the disputed claim in the map is “The Moon landing was faked“, not “Some people argue that the Moon landing was faked“. No one is objecting to the claim that some people argue it was faked – this is clearly true! The objection is to the claim that the Moon landing was faked. “Some people argue that” is a type of signpost as it points out the disputed claim.

Other words that are used to point out reasoning in a text include “therefore”, “hence”, “because”, “thus”, “so”, “since”, “for”, “as”:

John Doe is the most popular candidate therefore John Doe will win.

You should play chess because it is intellectually stimulating.

She must have left as her car isn’t here.

You should follow Mandy’s advice rather than Sue’s since Mandy has more experience than Sue in these matters.

Things are complicated however by the fact that some of these terms are not always used to signal reasoning. The following are examples of “since”, “for” and “as” used in a non-argumentative way:

Bob has limped since the accident.

Jones is currently working for the government.

He is as busy as a bee.

You can see that when such words are used in these ways, they do form part of the claims, and so could appear in a map. For example:

Bob has limped since the accident; if Bob has limped since the accident he must have been injured in the accident; thus Bob was injured in the accident.


Critical thinking and sophisticated reasoning requires an understanding of how logical arguments work.

An argument is a set of reasons for or against a conclusion that attempts to establish that either the conclusion is true of false. Arguments can have any number of steps or inferences. The order of the steps is called the structure of an argument. An argument map is a graphical representation of the structure of an argument. Arguments are made up of claims.

A claim is a statement that can either be true or false. In an argument map a claim is represented in a white box.

A conclusion or contention is a claim that is being supported by reasons. In an argument map, the main conclusion is placed at the top of the map, but an argument can contain any number of “intermediate” conclusions lower the map.

A premise is a claim that is offered in support of a conclusion.

A reason is a set of premises that work together logically in support of a conclusion. General, a single premise itself does not imply a conclusion, so most premises will be part of a reason with other premises. Mapping an argument and individuating reasons shows us which premises work together to form a reason and hence need to be acceptable for that reason to establish its conclusion. In an argument map a reason is represented by a green box that groups the premises together and line that connects to the conclusion.

An objection is a reason against the conclusion. In an argument map, objections are represented by red boxes and lines. (Please note that for ease of communication we will often use the word “reason” to refer to both reasons for and against a claim, i.e. the positive reasons that support it and the objections that oppose it.)

In the context of argument mapping, we often use the word ‘inference‘ to refer to a reason and its conclusion. Argument evaluation takes place at the level of these inferences or steps, so it’s important to be able to refer to them. In an argument map, the green and red lines connecting reasons and objections to conclusions so the inferences. Argument maps contain reference numbers that can be used to refer to specific references easily when pointing is not possible. e.g. “There is a fallacy in the inference 2A to 1A-a”. We can also use the term ‘argument unit‘ to refer to a conclusion and its reason.

Argument signposting is the words in the argumentative text such as “therefore” and “because” that tells the reader what the intended argument structure is. It can be useful to pay attention to the signposting when mapping an argument, but aren’t included in the argument itself because they are replaced by the lines indicating the argument structure.


Most of the lessons will have two types of practice.

  1. Brief quizzes on some of the key points raised in the lesson.
  2. Argument mapping practice activities of variously levels of challenge.

It is the argument mapping practice where you will hone your skills and understanding, and the reading and quizzes are primarily to help you understand these mapping activities. If you are comfortable with the concepts covered in the text, the quizzes can be skipped.