2.2 The Structure of Arguments

To see all of this more clearly, we need to take a look at how arguments work. But first things first – we need a more precise definition of what we mean by an argument in the first place. That’s easy enough:

An argument is a series of statements where some of these statements are intended to provide evidence or support for others. When we argue we are attempting to establish some claims on the basis of other claims.

As sets of statements, arguments involve the declarative use of language. Declarative statements (or propositions) are just sentences that state stuff, they make claims, and so they can be either true or false. So when we are looking at arguments we are deliberately ignoring the many other ways we can use language, such as asking questions, making commands, expressing feelings. When we are offering an argument we are making a series of claims in which some are supposed to provide support for others. The statements that are doing the supporting are known as premises. The statement that is being supported, the point of our argument is called the conclusion.

It is, however, sometimes difficult to tell whether a set of sentences is an argument or not. Let us consider a few examples:

Parents should have the right to make decisions about their own children’s healthcare.
Why should other people mess around in their business?
And please, let’s keep the lawyers out!

This may seem like an argument, so how can we tell for sure? Simply by checking whether this set of sentences is a set of statements where some are intended to provide support for others. So, how many statements are there here? Only one: the first sentence is a statement, the second is a question and the third is a command. In other words, even though this looks at first like an argument it is really just a single claim with no real argument given in support.

What about the next example? How many statements are in these sentences? And do any of them really offer support for any of the others?

I am convinced that aliens are living among us and you should be convinced as well.
I have really good evidence for this claim.

Well this is almost an argument, but not quite. There is a claim being made here: aliens are living among us. But there is no real support given for this claim, only the insistence that this person has some unknown evidence. Before we can start to evaluate this evidence to see whether it really supports the claim, we need to see it. So here we have only two separate statements without a real argument yet.

Now consider the following example:

Christopher Columbus was a criminal, because anyone who kills innocent people, kidnaps others, and steals their valuables is a criminal and that is just what he did.

Here the grammatical form is a little misleading. This is an argument in spite of the fact that there is only one sentence. Why? Because this one sentence expresses a few different claims or propositions and some of these claims are offered as supports for others. We can see this if we break it up into individual claims and change the order around like so into standard form with the premises listed as individual statements and the conclusion written last.

Anyone who kills people, kidnaps other people and steals their valuables is a criminal.
Christopher Columbus did all of those things.

So Christopher Columbus was a criminal.

Perhaps this is not yet a very convincing or complete argument, but at least it is an argument unlike the first examples.

It is not always so clear which statements in an argument are the premises and which statement is the conclusion. Often, but not always, these are signaled with one of a number of typical words or phrases that function as premise or conclusion indicators. Paying attention to these typical words and phrases can help you to disentangle the argument from the peculiarities of a writer’s style.


To help guide us through an argument a writer or speaker who is presenting an argument might use the following expressions and phrases to show what the argument rests on. These are premise indicators.

  • Because
  • Since
  • In light of the fact that
  • In view of the following evidence

This is not an exhaustive list. Basically, when reading an argument you can pick out the premises by asking yourself where the writer is starting from and where he or she is going. The first is the set of premises and the second is the conclusion.


It is often the case that arguments are presented with the conclusion first in order to emphasize where the discussion is supposed to be going. The following common words are often used to indicate a statement that is supposed to play the logical role of the conclusion of an argument.

  • Therefore
  • It follows that
  • Thus
  • It should be clear that

These words and phrases indicate that this is where the writer (or speaker) is going with the argument and they are often used at the beginning of an informal argument to orient us, even though logically speaking they are last. For example, when a lawyer begins her argument in court with the claim, “Your honor, ladies and gentlemen of the jury, my client is not guilty,” and then goes on to present the evidence, she is reversing the logical order for rhetorical effect. This is fine in everyday life, but since it can be confusing, when we look at arguments explicitly here we will look at them in standard form with the premises first and conclusion last.

Pattern of reasoning

One other thing to watch for when looking at arguments is words and phrases that indicate the structure of the reasoning itself. These are ways of pointing out exactly how the premises are supposed to support the conclusion, and so are indicators of the pattern or form of reasoning involved. Some examples are:

  • Because of these, that has to be true.
  • If this then that, otherwise this.
  • All of the above is true so this means…
  • This is the only option that makes sense.
  • If we assume that this is true we get a ridiculous result so it can’t be true.

These indicate the general logic form of argument being followed. Is it a matter of necessity, other conditions present or absent, summation of influences, or a process of elimination, or are we showing something indirectly by showing that denying it makes no sense? The more formal study of logic looks carefully at these and many other different patterns of reasoning, and we will meet them at various points in our discussions of arguments about topics in ethics.