Logical Arguments

Anything you read that includes an attempt to persuade you to think a certain way is likely to include logical argument as part of that persuasion. Philosophers are trained to study arguments, the reasoning and logic behind them, and the validity of their claims. In an English course, you will not analyze arguments in as much depth or detail as you would in a course on Philosophy or Logic, but you should still be familiar with key components of argumentation. Knowing the basic elements of an argument will help you identify the logic behind any arguments you read and also help you construct effective arguments in your own writing.

Elements of an Argument

An argument is a claim that contains premises which support a conclusion. In analyzing arguments, you can first look for the claim, or a statement or opinion on a topic. Claims are also called statements or propositions. For example, all of the following are claims:

1. 1. • This class is easy.
      • The Detroit Lions have the potential to make the NFL playoffs.
      • Democratic socialism is superior to a pure democracy.

Each of these could be the start of an argument, but they are incomplete arguments as-in; an argument needs both a claim and a conclusion. A premise is a claim, or piece of evidence, that supports the conclusion, and a conclusion is the main idea (or the “so what?”) of the argument, which is supported by the premises. Now let’s look at the examples above as premises, and we add in a conclusion to make them an argument. For example:

1. 1. • This class is easy so it should not be mandatory.
      • The Detroit Lions have the potential to make the NFL playoffs because they have three of the best players in the league.
      • Democratic socialism is superior to a pure democracy because it results in better outcomes and greater equality for more people.

An argument is an assertion that contains both a conclusion and a supporting premise. It is a statement of fact or opinion that is based on evidence, or premises. Keep in mind that not all statements are arguments, and some statements may contain multiple arguments.

A conclusion is the main claim of an argument that is supported by one or more premises. It is the logical result of the relationship between the premises. Identifying the conclusion is the first step in understanding the argument.

But how do you identify the conclusion? Follow these steps:

1. 1. 1. Ask, “Is the statement the main point, or is it a claim given to support another statement in the argument?”
      2. Identify the indicator word that often precedes the conclusion, such as:
         • therefore
         • thus
         • this means
         • this shows
         • as a result
         • it follows that
         • that’s why
         • this suggests
         • consequently
         • hence
         • so
         • accordingly

A premise is a reason offered as support, or evidence, for another claim. It is often indicated by these words:

1. 1. • because
      • for
      • as
      • since
      • inasmuch as
      • as shown by
      • given that
      • as indicated by
      • the reason is that

Consider the following statement:

1. 1. • Today’s freshmen cannot write very well. Joe is a freshman, so he must be a poor writer.

The premises and conclusion are identified as follows:

Practice identifying the premises and conclusions

In order to identify the premises and conclusion, you should first rewrite the argument in standard form. You do this by identifying which claim is the conclusion, then working backward to identify which claims are premises that support the conclusion. It should look like this:

Standard Form
Premise 1:
Premise 2:
Conclusion:

Figure 1. Breaking down an argument into the standard form can help you identify the premises and conclusion.

Evaluating Arguments

A formal argument may be set up so that, on its face, it looks logical. However, no matter how well-constructed the argument is, the premises must be true or any inferences based on the premises will be unsound.

One way to test the accuracy of a premise is to determine whether the premise is based upon a sample that is both representative and sufficiently large, and ask yourself whether all relevant factors have been taken into account in the analysis of data that leads to a generalization. Another way to evaluate a premise is to determine whether its source is credible. Are the authors identified? What is their background? Was the premise something you found on an undocumented website? Did you find it in a popular publication or a scholarly one? How complete, how recent, and how relevant were the studies or statistics discussed in the source? Take all of these things into consideration when evaluating an argument.