Common logical fallacies and reasoning errors - Causation an...

Learning Outcomes

By the end of this article, you will be able to identify, explain, and evaluate arguments that confuse correlation with causation on the LSAT. You will understand core reasoning errors, distinguish valid from flawed causal claims, and apply effective techniques to expose or resolve causation/correlation fallacies in exam questions. These skills are essential for answering LSAT logical reasoning and reading comprehension items that test the validity of argumentation.

LSAT Syllabus

For LSAT, you are required to understand the distinction between correlation and causation, recognise standard forms of fallacious causal reasoning, and analyze or evaluate arguments accordingly. This article will support your revision, especially by focusing on:

• recognising the difference between correlation and causation in argument stimuli
• identifying reasoning errors involving flawed causal claims
• applying techniques for strengthen and weaken questions involving causality
• differentiating between valid and invalid reasoning in LSAT argument passages
• avoiding common traps in LSAT logical reasoning questions related to cause/effect thinking

Test Your Knowledge

Attempt these questions before reading this article. If you find some difficult or cannot remember the answers, remember to look more closely at that area during your revision.

1. When does an argument commit a correlation vs. causation fallacy?
   1. When it provides sufficient evidence for causation
   2. When it assumes correlation proves causation
   3. When it distinguishes between the two
   4. When it offers alternative explanations
2. Which of the following is a valid way to weaken a causal argument on the LSAT?
   1. Prove the effect doesn't occur
   2. Identify a possible third factor explaining the correlation
   3. Assume the cause occurred in every case
   4. Ignore the data presented

3. True or False? If two events occur together, it always means one is the cause of the other.

4. What is the "post hoc ergo propter hoc" fallacy and why is it flawed reasoning on the LSAT?

Introduction

Many LSAT arguments involve claims about what causes what. However, the exam frequently tests your ability to spot mistakes in reasoning where correlation is confused with causation. Understanding how to analyse these errors, and knowing the classic traps, is critical for success in LSAT logical reasoning and reading comprehension sections.

In this article, you will learn the hallmark signs of correlation/causation errors, how to analyze flawed causal reasoning, and the best strategies for answering LSAT questions that involve arguments about causes and effects.

Key Term: correlation
A statistical relationship or pattern where two variables or events tend to occur together or change together; does not imply that one causes the other.

Key Term: causation
A direct relationship where a change in one event or variable directly brings about a change in another; cause leads to effect.

Key Term: post hoc ergo propter hoc fallacy
The reasoning mistake of assuming that because one event followed another, the first event must have caused the second—a classic LSAT fallacy.

Correlation vs. Causation: The Difference

Arguments often begin with an observed association between two phenomena. For LSAT, it is essential to determine whether the evidence supports only a correlation or if a true causal relationship is established. Remember: correlation alone does not justify a claim of causation.

Worked Example 1.1

Study: "People who drink more coffee are more likely to score highly on standardized exams."
Argument: "Therefore, drinking more coffee causes higher exam scores."

Answer:
This argument confuses correlation with causation. There may be a link (e.g., students who study more both drink coffee and get higher scores), but coffee is not necessarily the direct cause of better results.

Recognising Causation Errors on the LSAT

LSAT arguments that make causal mistakes commonly do one or more of the following:

• infer causation based solely on the fact that two things occur together (correlation)
• fail to consider possible alternative explanations (e.g., a third factor causes both)
• treat changes in one variable as definite proof it caused change in another
• ignore the possibility of reverse causation (the effect might actually cause the supposed cause)
• assume temporal order alone shows causation ("after X, therefore because of X")

Key Term: alternative explanation
A different possible cause that could explain the observed correlation instead of the one claimed in the argument.

Common Causal Reasoning Flaws

Flawed arguments about causation often appear in several forms on the LSAT, including:

1. Simple Correlation Assumed to Show Causation
   "Event A and Event B occur together. Therefore, A causes B."

2. Temporal Sequence = Causal Relationship
   "Event A happened before Event B; therefore, A caused B."
   This is the "post hoc ergo propter hoc" fallacy.

3. Overlooking Third Variables
   "A and B occur together, so A causes B"—but perhaps C causes both.

4. Ignoring Possible Reverse Causation
   "A and B are linked; must be A causes B."
   But perhaps actually, B causes A.

Worked Example 1.2

A college observes: "Applicants who visit campus are more likely to accept our admission offers. Therefore, visiting campus causes applicants to choose our college."

What is wrong with this reasoning?

Answer:
The argument ignores alternative explanations. For instance, students already invested in the college are both more likely to visit and more likely to accept the offer. The visit may reflect interest, not cause the decision.

Strategies for Analysing Causal Arguments

When you see a causal claim on the LSAT, ask:

• Is there direct experimental evidence, or just an observed correlation?
• Could there be another cause (a third variable)?
• Is reverse causation possible?
• Does the argument rule out coincidence or random chance?

Strengthen and Weaken Causal Arguments

• To strengthen: Show the effect does not occur when the cause is absent, or rule out alternative causes.
• To weaken: Introduce a plausible alternative explanation or evidence that the cause is not always followed by the effect.

Worked Example 1.3

Argument: "Whenever the power plant operates, fish deaths in the river increase. Thus, the power plant's operation causes fish deaths."

Which of the following would most weaken this argument?

A) A new chemical factory upstream began dumping waste just before the increase in fish deaths
B) Fish deaths occurred only after the power plant began using a new cooling method
C) The power plant operated at the same capacity last year, but fish deaths were much lower
D) The same species died in other rivers with no power plant

Answer:
Option A most weakens the argument by introducing a plausible alternative cause (upstream chemical waste), showing the correlation could be due to a third factor.

Exam Warning

Many LSAT questions will present tempting answer choices that restate the observed correlation in new words—be careful not to pick these unless the question asks for a summary of results, not a causal justification.

Revision Tip

On the LSAT, always question the leap from "Event A and Event B occur together" to "A causes B". Most arguments require more than a temporal link or simultaneous occurrence to establish causality.

Summary

Table: Common Causal Fallacies and Their LSAT Triggers

Key Point Checklist

This article has covered the following key knowledge points:

• Correlation (association) is not the same as causation (cause-effect)
• Arguments assuming causation from observed correlation commit a logical flaw
• The "post hoc ergo propter hoc" fallacy treats sequence as causation without justification
• LSAT strengthen/weaken questions involving causality often hinge on identifying alternative explanations or reverse causation
• Always look for other possible causes, reverse causality, and overlooked third factors in LSAT causal passages

Key Terms and Concepts

• correlation
• causation
• post hoc ergo propter hoc fallacy
• alternative explanation