5.3 Arguments

Components and Analysis of Arguments

Arguments are the building blocks of philosophical reasoning. Every argument has the same basic setup: one or more premises that provide reasons or evidence, leading to a conclusion that those premises are meant to support. Learning to pull apart arguments into these pieces is one of the most useful skills you'll pick up in philosophy.

Elements of an Argument

An argument has two types of components:

• Premises are statements that provide evidence or reasons supporting the conclusion. In the classic example: All men are mortal and Socrates is a man are both premises.
• The conclusion is the main claim the argument is trying to prove. In that same example: Therefore, Socrates is mortal is the conclusion.

Indicator words help you spot which statements are premises and which is the conclusion. This matters because arguments don't always put the conclusion at the end.

• Premise indicators signal that a reason or piece of evidence is coming: because, since, given that, as, for
• Conclusion indicators signal the main claim: therefore, thus, hence, so, consequently, in conclusion

For example, in the sentence "Since all men are mortal, and Socrates is a man, it follows that Socrates is mortal," the word since flags the premises, and it follows that flags the conclusion.

Identifying Components in Sample Arguments

When you're handed an argument and asked to break it down, follow these steps:

1. Find the conclusion first. Ask yourself: What is this person ultimately trying to convince me of? Look for conclusion indicator words, and check the beginning and end of the passage, where conclusions most often appear. For instance, in an argument about criminal justice, the conclusion might be The death penalty should be abolished.

2. Identify the premises. These are the reasons offered in support of that conclusion. Each premise should be a distinct claim. For the death penalty example, the premises might be: The death penalty is irreversible and The death penalty does not deter crime.

3. Determine how the premises connect to the conclusion. Do the premises, if true, actually give you good reason to accept the conclusion? The premises should logically lead to or support the conclusion. If a premise seems unrelated to the conclusion, that's a sign the argument may have a problem.

Evaluating Arguments

Once you've identified the parts of an argument, the next question is: Is this a good argument? There are two separate things to evaluate, and keeping them distinct is one of the trickiest parts of this unit.

Logical Structure vs. Truth of Claims

Evaluating logical structure means asking whether the conclusion follows from the premises, regardless of whether those premises are actually true. This is about the form of the argument.

• A valid argument has a structure where, if the premises are true, the conclusion must be true. The classic form: All A are B; C is A; therefore C is B. No matter what you plug in for A, B, and C, that structure guarantees the conclusion.
• An invalid argument has a structure where the conclusion does not necessarily follow, even if the premises happen to be true. Consider: All dogs are mammals; all cats are mammals; therefore all cats are dogs. Both premises are true, but the conclusion obviously doesn't follow. The logical structure is broken.

Assessing the truth of claims means asking whether the premises are actually true in the real world. This is about the content of the argument.

• A sound argument is valid and has all true premises. Example: All men are mortal; Socrates is a man; therefore Socrates is mortal. The structure is valid, and both premises are true, so the conclusion is guaranteed to be true.
• An unsound argument fails on at least one count: it's either invalid, or it has at least one false premise (or both). Example: All birds can fly; penguins are birds; therefore penguins can fly. The structure is valid, but the first premise is false, so the argument is unsound.

Here's where students often get tripped up. These two dimensions are independent, which creates some counterintuitive combinations:

• Valid but unsound: All mammals lay eggs; platypuses are mammals; therefore platypuses lay eggs. The logical form works perfectly, but the first premise is false, making it unsound.
• Invalid with true premises and a true conclusion: Socrates is a man; Socrates is mortal; therefore all men are mortal. Every statement here happens to be true, but the conclusion doesn't logically follow from those specific premises. The structure is invalid because those two facts about Socrates don't prove a universal claim about all men.

Reasoning and Critical Thinking

A few related terms worth keeping straight:

• Inference is the process of drawing a conclusion from premises or evidence. It's the mental step from "here's what I know" to "here's what follows."
• Reasoning is the broader activity of using logic to form judgments or reach conclusions.
• Logic is the systematic study of valid inference and sound argumentation. It gives you the rules for telling good arguments from bad ones.
• Argumentation is the practice of constructing and evaluating arguments.
• Critical thinking ties all of this together: it's the skill of analyzing and evaluating arguments to form well-reasoned judgments. Everything in this unit builds toward it.