2.9 - Argument Anatomy

Here, we’re diving into the nuts and bolts of arguments. On the LSAT, think of an argument as a series of statements meant to persuade or convince the reader.

Keep in mind that you need virtually no training in formal logic to understand arguments. We encounter arguments all the time, whether we realize it or not.

In this lesson we'll:

• Define premises and conclusions
• Teach you how to spot them
• Provide some indicator words that will help your spotting skills
• Introduce intermediate conclusions and compare them to main conclusions
• Touch on background information, a.k.a. when facts don't affect conclusions

Let's get started.

Conclusions and Premises

Arguments are made up of one or more premises and a conclusion.

You could think of premises and conclusions sort of like building blocks. Premises are the individual blocks that, once assembled, give us a structure—the conclusion.

On the LSAT, we must accept premises as true but argue viciously against the conclusions they attempt to support. In other words, grant the passage its facts without buying what it's trying to sell.

Premises

A premise is a piece of evidence or support. Support for what? Well, conclusions!

They can be facts, observations, or data. They can even be conclusions used in support of other conclusions (see Intermediate Conclusions below).

An argument’s strength relies heavily on its premises. Weak premises? Weak argument. Strong premises? Strong argument. It‘s that simple.

Spotting Premises

Spotting premises boils down to understanding when one idea supports another.

If you’re confused about whether a given clause or sentence is a premise, just ask yourself, ”Does this support something else in the passage?” If so, you‘ve got yourself a premise.

Consider the following information:

There's been a murder.
Tom has no alibi.
Tom was caught on security footage outside the crime scene.
Traces of the victim's DNA were on the shirt Tom was wearing in the footage.

If you read this and thought "Tom's in for a bad day," you're probably right. Why? Because each of these bits of information adds to the probability that Tom committed this murder.

In other words, if a clause or sentence improves the chances of something else being true, it's a premise.

Conclusions

A conclusion is an argument's central claim—what the author is trying to convince you of.

In other words, conclusions are the main point, the 'so what?' part of an argument. They attempt to persuade and therefore must be substantiated with evidence.

Conclusions can be explicit, stated for all to see, or implicit, an unstated consequence of the argument's premises (think back to Tom, our likely murderer).

Spotting Conclusions

Learning to spot conclusions is the first step to mastering arguments on the LSAT.

The conclusion's going to be what the passage builds toward—what the author's trying to convince you of. So spotting the conclusion is as simple as identifying which idea is supported by the rest.

Remember, though, the conclusion doesn't have to be stated explicitly.

Let's revisit the murder scenario:

There's been a murder.
Tom has no alibi.
Tom was caught on security footage outside the crime scene.
Traces of the victim's DNA were on the shirt Tom was wearing in the footage.

Each piece of information provides varying degrees of support to the unstated conclusion that Tom committed the murder. When put together, they make an even stronger case.

Be careful, though. In an earlier lesson, we discussed how the what-ifs are your job as a future attorney.

What if our boy Tom was second on the scene and saw the true murderer run off, holding the victim as they passed? Nothing in our fact set denies this possibility outright and we must keep it (and other alternatives) in mind.

Intermediate Conclusions

Intermediate conclusions are conclusions, too, but ones that provide support to an argument's overall conclusion. In other words, they're both a conclusion and a premise.

How might this look in Tom's case from earlier? Let's inject an intermediate conclusion and another premise.

There's been a murder.
The murderer will have been at the crime scene.
So the murderer must be someone with access to the crime scene and no alibi.
Tom has no alibi.
Tom was caught on security footage outside the crime scene.
Traces of the victim's DNA were on the shirt Tom was wearing in the footage.

The third sentence is an intermediate conclusion. But how can we be sure?

For starters, it tries to convince us of some characteristics the murderer must have. It's also supported by the second sentence—since the murderer will have been at the crime scene, the murderer must be someone with access and no alibi.

But the argument's main conclusion, while still unstated, remains that Tom committed the murder.

Consider the other premises about Tom in particular. Does Tom having no alibi support the idea that the murderer must be someone without an alibi and crime scene access? No, of course not. Moreover, our injections only add support to the idea that Tom's our perp because he fits the description provided by our intermediate conclusion.

That is to say, you can differentiate between main and intermediate conclusions by thinking about which one supports the other.

Indicator Words

As you study, you'll likely come across resources that suggest using indicator words to hunt for premises and conclusions.

While I admit these indicator words can be useful, I caution you from relying on them. The LSAT loves to sneak in little traps that break LSAT prep industry conventions. Rely on understanding, not test prep gimmicks.

That said, here are some indicator words that commonly introduce premises:

• Because
• Since
• For
• Given that
• As indicated by
• Due to
• In view of
• As
• In light of

And here's a list of indicator words that commonly introduce conclusions:

• Therefore
• Thus
• Consequently
• As a result
• Hence
• So
• Accordingly
• It follows that
• For this / these reason(s)

Background Information

All facts are not made equal on the LSAT. Occasionally, you'll read information in a passage that's completely unrelated to the conclusion being drawn.

I've heard other LSAT luminaries call these fun facts or filler, but I tend to think of these as background information.

Recall our murderer example. If I'd added something like "The temperature was 41 degrees at the time of the murder," into the mix, it wouldn't affect the likelihood that Tom committed the murder, at least not on its own.

These facts aren't meant to trick or mislead you. Remember, the test primarily evaluates your ability to understand what you read. In these instances, your job is to understand that what you've read has no bearing on the argument. That's it.

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That's it for Argument Anatomy. What would you add to this lesson? What would you remove? Leave me a comment to help me improve this course for you and your peers.

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Now that we understand the building blocks of arguments, we'll be learning how to put our understanding into practice by analyzing arguments. See you there!