Common logical fallacies and reasoning errors - False dilemm...

Learning Outcomes

After reading this article, you will understand what a false dilemma is, how false dichotomy reasoning undermines logical arguments, and be able to identify and evaluate such fallacies in LSAT questions. You will also know strategies to avoid falling for the trap of oversimplified “either/or” choices and to recognize when arguments incorrectly limit options. This knowledge will help you answer LSAT flaw and assumption questions with greater confidence.

LSAT Syllabus

For LSAT, you are required to understand how arguments can be flawed by only presenting limited options and how to challenge these errors.

• Identifying false dilemmas and dichotomies in written arguments
• Recognizing when arguments improperly restrict or misrepresent possible options
• Evaluating reasoning that presents only two choices when more may exist
• Applying these concepts to flaw, weaken, and assumption question types on the exam

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. Which of the following best describes a false dilemma fallacy?
   1. Arguing from anecdotal evidence
   2. Presenting only two possible choices when other alternatives exist
   3. Relying on circular reasoning
   4. Using ad hominem attacks

2. True or false? Arguments that present "either A or B" always fairly describe all possible options.

3. In an LSAT flaw question, why is it important to spot when an argument restricts the range of alternatives?

4. If an argument states, "We must either ban social media entirely or allow all content without limits," what fallacy is present?

Introduction

Arguments often rely on presenting alternatives. When an argument limits the options to just two—when more exist—it can commit a logical error known as a false dilemma or false dichotomy. On the LSAT, you must recognize when a stimulus or answer imposes an "either/or" structure that unfairly narrows possibilities, leading to poor conclusions and flawed reasoning.

Key Term: false dilemma
A fallacy where an argument claims only two options exist, ignoring other possible choices.

Key Term: dichotomy
Treating two things as mutually exclusive or exhaustive when they aren't necessarily so.

Arguments that fall into these traps can trick you into overlooking viable solutions, or persuade you by making alternatives seem unthinkable or implausible. This fallacy appears in LSAT flaw, weaken, and assumption questions, and is sometimes presented using extreme language or misleading phrasing.

Recognizing False Dilemmas

A false dilemma occurs when an argument says you must choose between two options—often phrased as "either X or Y"—when more options actually exist. This restricts the discussion and prevents proper evaluation of the issue.

Worked Example 1.1

A stimulus reads:
"Either we implement a four-day school week or education standards will drop dramatically. The only way to save our schools is to reduce the week to four days."

What’s the flaw?

Answer:
The argument presents just two alternatives—four-day weeks or falling standards—and ignores that other reforms (such as teacher training, improved materials, or different schedules) could also address education standards. This is a false dilemma.

Identifying Dichotomy Errors

Dichotomy errors occur when an argument splits possibilities into two sharply distinct categories—when other, more complex options are possible.

Worked Example 1.2

An author claims:
"A government is either completely honest or totally corrupt. Since this government has been caught in a minor scandal, it is corrupt."

Why is this reasoning flawed?

Answer:
The argument assumes only two states (honest/corrupt) exist, overlooking the range of conduct a government might display between those extremes. This forced dichotomy leads to an invalid conclusion.

How False Dilemmas Are Framed

Look for cues such as:

• "Either... or..."
• "The only way..."
• "We must choose between..."
• "Nothing else is possible..."

Often, strong or absolute terms ("always," "never," "must," "only") mark up a false dilemma.

Key Term: exhaustive options
A set of alternatives is exhaustive if it completely covers all possibilities.

Key Term: mutually exclusive
Two possibilities are mutually exclusive if they cannot be true at the same time.

Revision Tip

When you see an argument offering just two choices, ask yourself: are there other plausible alternatives? Consider if the argument unfairly narrows the scope of options.

False Dichotomy and Assumption Questions

False dichotomies are particularly relevant in assumption questions, where the argument relies on the idea that if one option is ruled out, the other must follow.

Worked Example 1.3

Stimulus:
"The proposed public transport plan is expensive, so we should not implement it; the only alternative is to keep using private cars."

What does the argument assume?

Answer:
The argument assumes no other affordable or efficient transport options exist. It ignores possible modifications, other transit plans, or improvements, making a false dichotomy assumption.

Exam Warning

On the LSAT, tempting wrong answers may state, "the argument presumes only two courses of action are available," or may themselves frame solutions in a binary manner—watch for answer choices that repeat the false dilemma.

Applications to LSAT Question Types

• In flaw questions, the false dilemma often appears as:
  "Fails to consider other possible explanations/alternatives,"
  or
  "Presumes that only two courses of action are available."
• In weaken questions, a correct answer may introduce or suggest a third alternative, showing that more options are possible.
• In strengthen questions, a correct answer may support the claim that the two options presented are truly exhaustive.

Worked Example 1.4

Argument:
"Citizens must either accept higher taxes or lose public parks. Since tax hikes are unpopular, we will lose our parks."

Which answer weakens the argument?
A) Suggests seeking private funding or other cost-saving reforms.

Answer:
Option A. By providing a third alternative, this answer shows the false dilemma in the argument—there are more than just higher taxes or park closure available.

Summary

Table: False Dilemma at a Glance

Key Point Checklist

This article has covered the following key knowledge points:

• False dilemma occurs when an argument illegitimately limits options to two
• Dichotomy errors are forced splits where a spectrum of possibilities exists
• Cues include "either/or" phrasing and extreme language
• Flaw, weaken, and assumption questions often test your ability to spot and address this reasoning error
• Good answers frequently challenge the completeness of the dichotomy or supply additional options

Key Terms and Concepts

• false dilemma
• dichotomy
• exhaustive options
• mutually exclusive