Deep Dive: Causality on the LSAT


Manhattan Prep LSAT Blog - Deep Dive: Causality on the LSAT by Ben Rashkovich

Causality is one of the biggest, baddest, trickiest topics on the LSAT—and it happens to be one of the most interesting, as well. (In fact, it’s my third-biggest LSAT crush!)

It’s a difficult concept in theory, but also in practice: causality shows up a lot in Strengthen/Weaken questions, which are statistically the most difficult questions in Logical Reasoning.

So let’s break it down.

What is Causality?

Causality is a directional relationship between two things. It implies that one thing “acts, happens, or exists in such a way that some [other] specific thing happens as a result,” to crib from

In other words, if A causes B, then we can say A brings about B in some way. This is abstract, so let’s use an example:

Sugar causes cavities.

Is this different from conditionality?

Yes! Let’s look at our above example that sugar causes cavities.

Can we conclude that having sugar is sufficient to say we have cavities? (In other words, can we say Sugar → Cavities?)

The answer is no—although we know sugar causes cavities, we don’t know that it alone causes cavities. It might be one of multiple causes that each independently are not sufficient, but together may be.

How about the other direction? Can we conclude that having cavities is sufficient to say we have sugar? (In other words, can we say Cavities → Sugar?)

This may be tempting, but we can’t conclude this either… Just because sugar causes cavities, doesn’t mean that only sugar causes cavities. Maybe you can develop cavities from multiple things, and sugar is just one of those things.

So causality and conditionality are separate concepts. They can certainly relate to one another, and in fact we sometimes see causality nested within conditional logic. (Example: If Ben causes the Earth to explode, then I will be sad.) But we want to be aware of their differences on the LSAT.

3 Types of Causality on the LSAT

On the LSAT, we see 3 related but distinct types of causality.

1. Causality As Fact

Most of the time, causality is cause for alarm—it’s almost always a flaw on the LSAT. But there are times when we can take a causal relationship for true. Consider the following argument:

Sugar causes cavities. Therefore, sugar is bad for you.

Now, our highly-trained, lawyer-like, LSAT-obsessed brains can spot the gap: the conclusion introduces a new term, “bad for you,” and links it to sugar. To make this argument valid, we’d need a sufficient assumption that resembles “having cavities is bad for you” or something similar.

More important for the current discussion, though, is our realization that the causal relationship is a fact. It’s given to us in a premise—so it’s unquestionable. This shows up not infrequently, so don’t discount any and all causal relationships as flaws—make sure they’re in the conclusion first.

Which brings us to…

2. Correlation/Causation Flaw

A correlation is a statistical relationship between two variables. Maybe when A goes up, B goes up. Maybe when A goes up, B goes down. Maybe when A goes down… You get the picture.

Correlations are evidence for causations, but they’re not proof. (This is a big topic in philosophy—read more here if you’d like!) If you’re wondering why they’re only evidence, consider that causality implies the relationship always holds, while correlations involve a fixed amount of data. (There’s room to quibble here philosophically, again, but let’s keep it to the LSAT for now.)

So our Correlation/Causation Flaw occurs when we have a correlation in a premise and a causal relationship in our conclusion. In other words, the speaker of the stimulus assumes that correlations prove causations. For example:

The more sugar you eat, the more cavities you get. Therefore, sugar causes cavities!

The flaw here is that the arguer moves from the correlation (as sugar increases, cavities increase) to a causation (sugar causes cavities).

How do we know that cavities don’t cause sugar? Or that something doesn’t cause both of them together, like soda high in sugar but with the special cavity-inducing Chemical X?

We don’t! And that’s where the flaw lies.

In ID the Flaw questions, this is our answer choice. In Strengthen/Weaken questions, this tells us how to find our answer choice. More on that in the last section.

3. Subtle Causal Conclusions

If you’re a real LSAT aficionado, you may have noticed that it’s possible to have a causal conclusion without a correlation in the stimulus… And what’s more, without clear causal indicators!

This shows up way more on Strengthen/Weaken questions, because ID the Flaw questions with the Correlation/Causation flaw need a correlation in the premises and causal language in the conclusion. It might be implied, so it could still be tough to spot, but this is a bigger danger zone for Strengthen/Weaken.

And as a result, noticing these subtle causal conclusions will go a long way to helping us identify correct answers in difficult Strengthen/Weaken questions.

Rather than looking for correlations in the premises that get turned into causations in the conclusion, we want to look for an event in the premises (defined loosely) and an explanation in the conclusion (defined similarly loosely).

In abstract terms:

X happened, therefore Y is the explanation.

This assumes Y causes X. (You can make an argument that it also might assume a conditional relationship… And depending on the language, you could be right. But recall that even if we had X → Y , we still don’t know Y explains X, just that having X tells us that we also have Y. Conditionality vs. Causality, folks! It’s a blast!)

Here are a few examples:

That bar is super crowded! Therefore, their drinks must be tasty.

(Causal assumption: Tasty drinks are causing people to patronize the bar. Maybe they have delicious $1 sliders and terrible drinks?)

My kid isn’t doing well in school. Thus, it must be all those darned video games, rotting her brain!

(Causal assumption: Playing video games causes one to do poorly in school. Maybe they’re playing video games to release the stress of under-performance in school, instead?)

Beep boop! My robo-dog has eaten my math homework. So I’ve got to conclude that he finds math homework delicious.

(Causal assumption: You figure it out for this one!)

Notice that we don’t have a correlation in our premise, and the causal language in the conclusion is, well, basically nonexistent.

Instead, what we’re looking for is the type of relationship established between the new term in the conclusion and the way the preceding argument functions. These are exceedingly tough, but with practice, you can figure out how to spot these types of causal arguments!

Recognizing Causality

Despite the fact that some causal arguments are hard to spot, there are some common cues that will tip us off in many instances. This list of causal indicators is by no means complete, but you might find it useful nonetheless:

  • Due to
  • By means of
  • Because of
  • As a result of/can result in
  • Explains
  • Contributes to
  • Leads to
  • Has led to
  • Stimulates
  • Causes
  • Induces
  • Produces
  • Has the byproduct of
  • Changes/increases/decreases in reaction to
  • Is a factor of
  • Has the effect of
  • Affected by
  • As a consequence of
  • If you want to _____, then you should ________

Some of these are overt. Some of them are subtle. Sometimes there’ll be very little in the way of explicitly warning you that you’re dealing with causality. Which brings us to…

Dealing with Causality

As mentioned above, when you’ve got a causal conclusion in an ID the Flaw question, you’ve pretty much got your answer. Bravo!

When it comes to Strengthen/Weaken, it’s a bit more complicated. However, we do have a handy-dandy system for dealing with causality on this question type as well:

To strengthen, we:

  • Eliminate an alternative cause
  • ID another situation where the cause and effect go together (Cause and Effect – furthering the correlation)
  • ID a situation where the cause is absent, and so is the effect (Control group)

To weaken, we:

  • ID an alternative cause
  • ID a counterexample (either a situation that gives us the cause but not the effect, or the effect but not the cause)
  • Point out reversed causality

You want to have these strategies at your fingertips to tackle the toughest causal arguments that the LSAT can throw at you. 📝

Don’t forget that you can attend the first session of any of our online or in-person LSAT courses absolutely free. We’re not kidding! Check out our upcoming courses here.

Ben Rashkovich is a Manhattan Prep LSAT instructor based in New York, NY. He’s a graduate of Columbia University, and he scored a 172 on the LSAT. He enjoys the mental challenge and logical acrobatics of the LSAT—and he feels that studying for the test can teach everyone to approach problems more rationally. You can check out Ben’s upcoming LSAT courses here!

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