Table of Contents
Informal fallacies of presumption occur when an argument quietly assumes something that it still needs to prove.
The reasoning looks neat, but the support is missing because a hidden assumption is doing the main work.
In Real Life: people accept such claims quickly because the assumption feels “obvious” and saves thinking effort.
Exam Point of View: NET questions often ask you to identify the fallacy and underline the exact assumed line or forced assumption.
1. Informal Fallacies of Presumption
These fallacies are called “of presumption” because they start by presuming (taking as true) what is not yet established.
A good test is simple: if you remove the hidden assumption, the argument collapses.
1.1 Core Idea Behind Presumption Errors
Presumption errors usually appear in one of these ways.
- The conclusion is already inside the premise in a disguised form.
- The question forces you to accept an accusation or claim before you answer.
- A cause is declared without proper proof of causation.
- A general rule is applied to an exception case without care.
- A general rule is created from a tiny or biased sample.
1.2 Quick Classification Table
| Fallacy | What is wrongly assumed | One-line test |
|---|---|---|
| Begging the question | Conclusion is already true | “Did you prove it or repeat it?” |
| Complex question | Hidden claim is already accepted | “Why must I accept that assumption?” |
| False cause | Causation is already established | “Is the cause really tested?” |
| Accident | Rule applies to every case | “Is this an exception case?” |
| Converse accident | Few cases represent all cases | “Is the sample big and fair?” |
2. Begging the Question
Begging the question is also called petitio principii, which means “assuming the principle.”
In simple words, the argument assumes what it needs to prove, so it moves in a circle.
2.1 What Exactly Goes Wrong
The premise does not give independent support. It only restates the conclusion using the same idea.
- The conclusion is repeated with slightly different words.
- A key term is defined using itself.
- The “reason” is only a synonym of the claim.
2.2 Common Forms You Must Know
2.2.1 Direct Circularity
This is the most obvious form.
- “This rule is correct because it is the right rule.”
- “He is honest because he never lies.”
2.2.2 Restating the Conclusion as Evidence
Here the words change, but the meaning stays the same.
- “This policy is beneficial because it is good for society.”
- “She is a great teacher because she teaches very well.”
2.2.3 Circular Definition
A term is explained using the same term again, so nothing new is learned.
- “Justice means being just.”
- “Democracy is a democratic system of governance.”
2.3 Quick Recognition Signals
Begging the question often hides behind confident words.
- Words like “obviously,” “clearly,” and “everyone knows” appear as fillers.
- The explanation feels like a re-labeling, not real proof.
- If you replace fancy words with simple words, it becomes a loop.
2.4 How to Correct It
A good correction asks for independent evidence.
- Ask for a reason that does not contain the conclusion.
- Ask for an example, data, or observation from outside the claim.
- Ask the speaker to define key terms without using the same idea again.
3. Complex Question
A complex question is also called a loaded question because it “loads” a hidden assumption into the question itself.
It forces you into an unfair choice because any direct answer makes you accept the hidden claim.
3.1 How the Trap Works
A single question secretly contains two parts.
- Part one is an unstated assumption.
- Part two is the question you are asked to answer.
When you answer part two directly, you accidentally accept part one as true.
3.2 Typical Patterns of Complex Questions
3.2.1 “Stop” and “Again” Triggers
These words assume something already happened.
- “Have you stopped wasting time in class?”
- “Why did you again submit the assignment late?”
3.2.2 “When” and “Why” Accusation Triggers
These words can assume guilt or a negative habit.
- “When did you start copying homework?”
- “Why do you always disturb the lecture?”
Situational Example: A student is asked, “When did you start cheating?” If the student says “last week,” the student accepts cheating. If the student says “today,” the student still accepts cheating.
3.3 How to Answer Safely
The correct logical move is to reject the assumption first.
- Say that you do not accept the hidden claim.
- Request a fair question that does not carry an accusation.
- Answer only after the question is corrected.
3.4 Complex Question vs Simple Question
A simple question asks for information.
A complex question demands acceptance of an assumption before information is given.
4. False Cause
False cause happens when an argument claims a cause without proving the causal link properly.
Two events may occur together, or one may follow the other, but that does not automatically prove causation.
4.1 Why Causation Is Hard
Causation means the cause truly produces the effect.
Correlation means two things happen together. Correlation can happen even when there is no causal link.
A common reason for confusion is a confounder, which means a third factor that influences both events in a hidden way.
4.2 Post Hoc Ergo Propter Hoc
Post hoc means “after this.” The fallacy claims that because B happened after A, A caused B.
4.2.1 Typical Pattern
- A happens.
- B happens later.
- Therefore, A caused B.
4.2.2 Examples
- “I started using a new pen and then I scored high, so the pen caused my marks.”
- “After the new timetable started, students became disciplined, so the timetable caused discipline.”
4.2.3 Why It Is Wrong
Sequence is not proof. You still need evidence that the effect depends on the cause and not on some other factor.
4.3 Non Causa Pro Causa
Non causa pro causa means “a non-cause is treated as the cause.”
Here a cause is provided, but it is the wrong cause.
4.3.1 Common Ways It Appears
- An irrelevant factor is given as a cause.
- A coincidence is promoted as a cause.
- A visible factor is blamed while the real factor remains hidden.
4.3.2 Examples
- “Students failed because the classroom walls are blue.”
- “He got fever because he studied mathematics.”
- “The project succeeded because the team used a lucky slogan.”
4.4 Quick Cause Testing Steps
Use this simple testing idea before accepting a causal claim.
- Check whether the effect can happen without the claimed cause.
- Check whether the cause can happen without the effect.
- Check whether a third factor can explain both events.
- Check whether the cause logically and scientifically connects to the effect.
Exam Point of View: In NET, statements with “after that,” “since then,” “because of this only,” and “as soon as” often hide post hoc. If the claim ignores other factors, it usually fits false cause.
5. Accident
Accident is a fallacy where a general rule is applied to a special case where the rule does not fit properly.
The rule might be mostly true, but real life contains exceptions.
5.1 Structure of Accident
- A general rule is stated.
- A special case appears.
- The rule is applied without considering the exception.
- A wrong conclusion is produced.
5.2 Examples with Explanation
- “Cutting a person is a crime, so surgeons are criminals.”
This is wrong because surgery is a justified exception with a different purpose and consent. - “Phones are banned in class, so a student cannot call an ambulance during an emergency.”
This is wrong because emergencies are special cases where the rule is not meant to block safety.
5.3 How to Catch Accident Quickly
- Ask whether the rule is being applied to an exception situation.
- Ask whether context changes the meaning of the action.
- Ask whether the rule itself was created with an implied exception.
6. Converse Accident
Converse accident is the reverse movement of accident.
Instead of applying a rule to an exception, it creates a rule from a few special cases.
This is popularly known as hasty generalization because the conclusion is too broad for the evidence.
6.1 Why It Happens
People rely on quick experience, stories, and a few observations.
They treat personal experience as if it is equal to proper sampling.
6.2 Typical Structure
- A few cases are observed.
- The cases are not representative.
- A general claim about everyone is made.
6.3 Examples with Explanation
- “Two students from that college were rude, so all students of that college are rude.”
This is wrong because two students cannot represent the entire college population. - “I met one dishonest shopkeeper, so all shopkeepers are dishonest.”
This is wrong because the sample is tiny and biased, and it ignores base rates.
6.4 Sample Problems You Must Mention in Answers
These are the exact weaknesses exam questions expect you to point out.
- Sample size is too small.
- Sample selection is biased.
- Only extreme cases are noticed.
- Anecdotes are treated as statistics.
7. Accident vs Converse Accident
These two are commonly confused, so learn the direction of error.
7.1 Direction Rule
- Accident moves from rule to exception.
- Converse accident moves from cases to rule.
7.2 Comparison Table
| Point | Accident | Converse accident |
|---|---|---|
| Movement | Rule to special case | Special cases to rule |
| Main mistake | Ignores exceptions | Ignores representativeness |
| Typical clue | Strict rule applied blindly | “All,” “always,” from few cases |
Key Points – Takeaways
- Presumption fallacies occur when an argument depends on a hidden assumption instead of real evidence.
- Begging the question repeats the conclusion in the premise, so the argument becomes circular.
- Circular definition is a common form of begging the question and it gives no new information.
- Complex question forces acceptance of a hidden claim before you can answer properly.
Exam Point of View: In MCQs, check whether the “reason” contains the same idea as the “claim.” If yes, it is usually begging the question. If the question contains an accusation, it is usually complex question.
- Post hoc treats “after that” as “because of that,” which is a timing mistake.
- Non causa pro causa blames a wrong factor as the cause and ignores the real explanation.
- Accident applies a general rule to an exception case where context changes meaning.
- Converse accident generalizes from a small or biased sample to a broad conclusion.
Exam Point of View: When options include both accident and hasty generalization, identify the direction. If a rule is misused on an exception, choose accident. If a broad rule is made from a few cases, choose converse accident.
- Words like “always,” “everyone,” and “never” often signal hasty generalization when evidence is weak.
- Words like “stopped,” “again,” and “still” often signal complex question because they carry hidden assumptions.
- A good correction method is to ask for independent evidence, a fair question, or a representative sample.
How to Spot These Fallacies in 10 Seconds
Use this practical checklist while solving NET questions.
- If the reason repeats the claim, it is begging the question.
- If the question forces you to accept an assumption, it is complex question.
- If timing is used as proof, it is post hoc.
- If an irrelevant factor is blamed, it is non causa pro causa.
- If a rule ignores an exception, it is accident.
- If a big conclusion comes from a few cases, it is converse accident.
Summary Table for Fast Identification
| Clue words | Most likely fallacy |
|---|---|
| “clearly,” “obviously,” rewording the claim | Begging the question |
| “stopped,” “again,” “still,” “why are you always” | Complex question |
| “after that,” “since then,” “as soon as” | Post hoc |
| “because of X” where X is irrelevant | Non causa pro causa |
| Strict rule used in emergency or special case | Accident |
| “all,” “always,” “everyone,” from a few examples | Converse accident |
Examples
Example 1
In a classroom discussion, a student says, “Group study is best because it is the most effective way to study.”
This does not prove anything because “best” and “most effective” carry the same idea.
The statement only restates the conclusion using different words, so it fits begging the question.
Example 2
A teacher asks, “Have you stopped coming late to class?” and expects a yes or no answer.
This question assumes that the student was coming late earlier, even if there is no proof.
A logical response should first reject the assumption and then ask for a fair question.
Example 3
A person says, “After I installed a new app, my phone started hanging, so the app caused the problem.”
This claim depends only on timing, not on testing.
The real cause could be low storage, background updates, or a hardware issue, so this is post hoc.
Example 4
Ravi failed a mock test after wearing a new watch.
He told friends that the watch was unlucky and it caused his failure.
Later he realized he had not revised the weak topics at all.
He blamed the watch because it was easier than accepting poor preparation.
Example 5
Someone says, “Two online classes were boring, so online education is always boring.”
This is a broad conclusion based on a tiny and biased experience sample.
A proper conclusion needs many classes from different teachers, subjects, and formats.
Quick One-shot Revision Notes
- Presumption fallacies depend on an assumption that is not proved.
- Begging the question happens when the premise restates the conclusion without independent support.
- Circular definitions create the illusion of explanation but they add no new meaning.
- Complex question forces acceptance of a hidden claim inside the question.
- Post hoc confuses sequence with causation and uses “after” as proof.
- Non causa pro causa blames a wrong or irrelevant factor as the cause.
- Accident applies a general rule to an exception case where the rule is not suitable.
- Converse accident creates a general rule from a few special cases.
- Hasty generalization becomes stronger only when sample size is large and representative.
- A representative sample reflects the whole group fairly, not just one corner of it.
- Confounders are hidden third factors that can explain both events in false cause claims.
- In MCQs, always locate the hidden assumption before selecting the fallacy name.
Mini Practice
Q1) A student says, “This rule is correct because it is the right rule.” Which fallacy is this?
A) Begging the question
B) Complex question
C) Accident
D) False cause
Answer: A
Explanation: The “reason” repeats the conclusion in different words and gives no independent support.
Q2) A teacher asks, “Have you stopped copying in exams?” Which fallacy is this?
A) Begging the question
B) Complex question
C) Post hoc
D) Converse accident
Answer: B
Explanation: The question assumes the student copied earlier, so a direct answer accepts the hidden claim.
Q3) “After the new principal joined, results improved, so the principal alone caused the improvement.” Which fallacy is this?
A) Accident
B) Post hoc
C) Begging the question
D) Complex question
Answer: B
Explanation: It uses “after that” as proof of causation and ignores other factors like teaching methods and student effort.
Q4) “Cutting a person is a crime, so surgeons are criminals.” Which fallacy is this?
A) Accident
B) Converse accident
C) Non causa pro causa
D) Post hoc
Answer: A
Explanation: A general rule is applied to a special exception case where context and purpose change the meaning.
Q5)
Assertion (A): Converse accident is also called hasty generalization.
Reason (R): It draws a broad conclusion about a whole group from a few unrepresentative cases.
A) Both A and R are true, and R explains A
B) Both A and R are true, but R does not explain A
C) A is true, R is false
D) A is false, R is true
Answer: A
Explanation: The reason states the exact logic behind why it becomes a hasty generalization.
FAQs
What are informal fallacies of presumption?
They are reasoning errors where a hidden assumption replaces real proof and makes the argument look valid.
How do I identify begging the question quickly?
Check whether the reason repeats the claim using the same meaning or a synonym.
Why is a complex question unfair?
It forces you to accept a hidden claim, so any direct answer makes you agree with an assumption.
What is the key mistake in post hoc?
It assumes that if one event happens after another, the earlier event must be the cause.
Accident and hasty generalization look similar. What is the easiest distinction?
Accident misuses a rule on an exception, while hasty generalization makes a rule from a few cases.
What should I write in an exam answer for hasty generalization?
Mention small sample size, biased selection, lack of representativeness, and an over-broad conclusion.