Fallacies and Truth Theories - Comprehensive Study Notes
Fallacies: Definition and Purpose
Fallacy defined as a flaw or error in reasoning. It refers to a defect in the reasoning of an argument that causes the conclusion(s) to be invalid, unsound, or weak. Fallacies are faulty arguments that, although incorrect, are subjectively convincing.
Importance of studying fallacies:
Helps you learn what to avoid and what to pursue.
Analogous to doctors studying diseases to fight and prevent them.
Provides a foundation for evaluating and critiquing other arguments.
Formal vs Informal (Content) Fallacies
Formal fallacies: flaws rooted in invalid deductive structure; they are structural defects.
Informal (content) fallacies: flaws not in the structure but in the content or meaning of the argument.
Subtype distinction:
Structural fallacies (formal): faulty logical form.
Content fallacies (informal): faulty content or questionable content.
Formal Fallacies: Inductive Principles and Types
Two principles for higher probability in inductive reasoning: \begin{aligned}
&\quad \text{The wider the scope of the premises, the higher probability.}\
&\quad \text{The more representative the scope, the higher probability.}
\end{aligned}
Inductive Fallacy of Hasty Generalization:
Occurs when these principles are violated.
Example: A socio-economic study in Manresa involved four respondents (John, Mark, Chester, Ray) who are children of multimillionaire industrialists. Concluding that all Manresa students are children of multimillionaires would be a hasty generalization because the sample (4 out of ~2000 students) is a tiny fraction.
Deductive Fallacies
These fallacies are faulty patterns of deductive reasoning and include:
The Four-Term Fallacy
The Fallacy of Faulty Exclusion
The Fallacy of the Undistributed Middle
The Fallacy of Illicit Distribution
Faulty Conditional Syllogism
Faulty Inclusive Disjunctive Syllogism
The Four-Term Fallacy
A valid categorical syllogism must use exactly three terms, each used twice to refer to the same class. The four-term fallacy occurs when an argument uses more than three terms, breaking the term-usage rule.
Example (illustrative):
All dogs are animals. All cats are mammals. Therefore, all cats are dogs.
This uses four distinct terms: Dogs, Animals, Cats, Mammals; invalid due to mislinked categories.
The Fallacy of Faulty Exclusion
A valid syllogism must not unfairly exclude relevant possibilities; when exclusion is used to make a conclusion look more valid, the argument commits faulty exclusion.
Example #1:
All traditional politicians are not honest. The speaker of the lower house is not a traditional politician. So, he is honest.
This ignores other possibilities and over-simplifies by excluding relevant alternatives.
Example #2:
"The only reason the company is successful is because of its marketing team." Excludes factors like product quality, customer service, leadership, or market demand.
Conclusion wrongly attributes sole cause to marketing.
The Fallacy of the Undistributed Middle
In a valid syllogism, the middle term must be distributed at least once.
Undistributed middle occurs when the middle term (the term appearing in both premises) is not distributed, so the link between the two other terms is not properly established.
Example #1:
All high-quality goods are expensive. This product is expensive. Therefore, this product must have high quality.
Middle term "expensive" is not properly distributed.
Example #2:
All dogs are animals. All cats are animals. Therefore, all cats are dogs.
Middle term "animals" is not distributed; fails to connect cats to dogs.
The Fallacy of Illicit Distribution
Occurs when a term that is undistributed in a premise is distributed in the conclusion, improperly extending its scope.
Example #1:
All engineers are professionals. All engineers are logical. Therefore, all logical people are professionals.
Term "logical people" is not distributed in Premise 2 but is distributed in the conclusion.
Example #2:
All dogs are animals. No cats are dogs. Therefore, no cats are animals.
"Animals" is undistributed in the premise but distributed in the conclusion, unjustifiably broadening the claim.
Faulty Conditional Syllogism
Occurs when the causal link between premises and conclusion is wrong, commonly by affirming the consequent or denying the antecedent.
Example #1:
If I study, I will pass the test. I did not study. Therefore, I will not pass the test.
Reasoning is faulty because prior knowledge or luck could still lead to passing.
Example #2 (Consequence):
If it rains, the ground gets wet. The ground is wet. Therefore, it rained.
Other causes (sprinkler, dew) could explain wet ground.
Faulty Inclusive Disjunctive Syllogism
A faulty inclusion/disjunction fallacy occurs when one assumes that a disjunction excludes the other when it may be inclusive (both may be true).
Example #1:
Either Mary is at the gym, or she is studying. Mary is at the gym. Therefore, she is not studying.
She could be at the gym and studying simultaneously.
Example #2:
You can either go to college or get a job. You got a job. Therefore, you didn't go to college.
It is possible to both work and study.
Informal (Content) Fallacies
These fallacies are not primarily about form but about content or language manipulation.
Three groups:
Linguistic manipulation
Psychological warfare
Logical maneuvers
Linguistic Manipulations
Fallacies exploiting language, especially denotation vs connotation:
Denotation: the objective meaning of a word.
Connotation: the subjective attributes and emotional associations of a word.
These fallacies exploit connotation to mislead, persuade, or intimidate.
Prestige Jargon
Jargon = technical language used among experts; acceptable within a field but fallacious when used to intimidate non-experts or obscure points.
Mechanisms:
Can intimidate opponents by sounding like expert authority.
Can obscure arguments, making counter-argument difficult.
Examples:
A hospital note: replacing simple terms with overly technical phrasing to sound authoritative.
Consequences:
Twofold: impedes counter-argument and creates perceived expertise where there is none.
The Use of Jargon: Illustrative Example
When a school physician says: "circumorbital hematoma, regulated application of low-temperature compress, prognosis highly positive within ample time frame" instead of saying "black eye with cold compress; recovery in a few days." This is prestige jargon.
The Use of Jargon: Dual Effects
First effect: signals expert status to discourage disagreement.
Second effect: obscures points, hindering counter-argument.
Emotional Words
Fallacy of using emotionally loaded words to secure sympathies.
Context: political speeches and advocacy often rely on high-emotion terms and symbols.
Example: appeals to national heroes or oppressed groups to elicit emotional response rather than rational argument.
Double Talking (Euphemism)
Hides unpleasant denotations by using positive connotations.
Examples:
Gambling framed as "play here".
Tax increase described as "tax enhancement"; inflation as "price enhancement".
Marcos-era martial law described as "constitutional authoritarianism" instead of dictatorship.
Psychological Warfare
Targets sensuousness, emotions, will, and subconscious drives to mislead or persuade.
Main idea: people may be led by feelings rather than reason.
Subtypes include:
Meaning from Association
Misuse of Authority
Repeated Assertion
Attitude Fitting
Tokenism
Poisoning the Well
Rationalizing
Argumentum ad Baculum (appeal to force)
Argumentum ad Hominem (against the person)
Popularity/Ad Populum fallacy (appeal to the many)
Meaning from Association
Advertising tactic pairing products with unrelated, desirable ideas to transfer meaning.
Example: Alcohol and cigarettes associated with macho lifestyle.
Misuse of Authority
Citing an authority outside their field or expertise to support a claim.
Examples:
A national artist speaking on architecture or literature.
An actress recommending a fashion brand.
Repeated Assertion
The psychological effect of repeated claims, which can make falsehoods seem true over time (easier to accept when heard often).
Notably used historically (e.g., propaganda banners).
Attitude Fitting
Naming places or things to evoke desired attitudes (attraction or repulsion) to manipulate decisions.
Historical example: Greenland (ice) vs Iceland (fertile) naming to attract settlers and deter others.
Tokenism
Superficial gestures used to appear responsive while deferring real action and expenditure.
Campaign imagery of hugging a child or meeting with the poor to signal care while neglecting real policies.
Poisoning the Well
Pre-emptively discounting an opponent’s evidence or counter-arguments to block engagement.
Example: A professor discredits open-notes exams to bias future responses.
Rationalizing
Creating pleasant reasons to justify unpleasant actions when genuine reasons are unavailable.
Metaphor: "grapes sour, lemon sweet" illustrating biased rationalization.
Argumentum ad Baculum (Appeal to Force)
Forcing or threatening force instead of using reason.
Historical example: Galileo and Copernicanism confronted by edict and imprisonment rather than scientific argument.
Argumentum ad Hominem
Attacking the person instead of addressing the argument.
In forensic settings, sometimes admissible to challenge credibility, but generally a logical flaw when used to dismiss arguments.
Popularity (Ad Populum)
The fallacy that if many people do something, it must be true or effective (e.g., a diet pill with many users).
Logical Maneuvers: Subtle Reasoning Tricks
This group aims to fool the cognitive and analytical parts of the mind; often requires knowledge of logic.
Fallacy of Composition
What is true for parts is assumed to be true for the whole.
Example #1: If Mark, Jun, Carl, and Jim are good vocalists, their quartet must be good.
Example #2: If five point guards are good, their basketball team must be good.
Example #3: All atoms in a book are invisible; therefore, the book is invisible.
Fallacy of Division
Opposite of composition: what is true of the whole is assumed true for each part.
Example: Yemen is poor; therefore, Ali Abdullah Saleh is poor.
False Dilemma (False Dichotomy)
Presents only extreme choices, omitting middle ground; pressuring to accept one option.
Examples:
"If you think education is expensive, try ignorance."
"An increase in military budget means more safety; a cut means less safety."
Note: Often ignores neutral or intermediate positions.
Argument of the Beard
Exaggerates the middle ground by arguing that if you can add one more, you can keep adding more, ad infinitum.
Purpose: highlight that gradual changes do not necessarily eradicate real differences between extremes.
The Strawman
Misrepresents an opponent’s position to attack a weaker version (a strawman) rather than the actual position.
Example: Ridiculing evolution as if it claimed humans descend from apes in a simplistic way; the strawman misrepresents the theory.
Slippery Slope
Claims that a small first step will lead to a chain of related events culminating in a significant (often negative) outcome.
Also known as the grand domino theory.
Example: A judge case argument that one action will inevitably lead to widespread corruption or catastrophe.
Diversion (Red Herring)
Diverts attention from the main issue to a related but irrelevant issue.
Examples: In budget debates, arguments about salaries or unrelated promises. In politics, discussing promises or celebrity anecdotes instead of policy.
Begging the Question
Circular reasoning: the conclusion is assumed in the premises without proper supporting evidence; the argument rests on its own claim.
Example #1:
Question: What is an honest person? Answer: An honest person is someone who is honest.
Example #2:
Cartoon claim: Government teachers are not well-paid because those responsible for the budget are not competent; they are not competent because their teachers are not enthusiastic; they are not enthusiastic because they are not well-compensated. It loops back to the premise without independent support.
Appeal to Ignorance
The fallacy of assuming that a lack of evidence proves a claim true or false.
Examples:
If we cannot prove aliens don’t exist, it does not prove they do exist.
The existence of God is not proven or disproven by lack of proof alone.
Post Hoc ergo Propter Hoc (False Cause)
Mistakenly linking two events due to chronological order; assuming A caused B simply because A occurred before B.
Example: Drinking bottled water and then getting sick; inferring the water caused the illness without a causal explanation.
Contradictory Assumption
Presenting two assumptions that cannot both be true at the same time.
Example: Promising to cut taxes in half while doubling government services.
Two Wrongs Make a Right
Justifying a fault by pointing to another fault by others; comparing ill-advised actions to justify similar wrongs.
Example: Responding to human rights criticisms by pointing to other countries’ abuses.
Lifting Out of Context
Distorting meaning by cutting words or phrases from their original context; context shapes meaning.
Example: A pro-gun leaflet quotes a mayor suggesting guns are a must, but the full statement concerns a society with high crime and disorder, i.e., a broader context.
What Is an Argument? Basic Structure
An argument is a system of claims intended to support a conclusion.
Core elements:
Conclusion: the claim the argument aims to establish.
Premises: supporting reasons or claims used to justify the conclusion.
Inference: the mental process of drawing a conclusion from the premises (not a visible part of the argument).
The Theories of Truth (Epistemology)
Epistemology: the philosophy of knowledge; concerned with how we know what is true and the standards used to evaluate claims.
Four classical theories of truth:
1) The Correspondence Theory
Truth corresponds to observable reality.
Dominant in science: what we observe in experiments is taken as true if it matches reality.
2) The Coherence Theory
Truths are true if they follow logically and coherently from a set of axioms or accepted propositions.
Arguments must flow logically from premises to conclusions; a fallacious argument is false because it violates logic.
3) The Consensus Theory
Truth is what is agreed upon by a community or by experts.
Example: mask-wearing during COVID-19 is accepted based on expert consensus.
Note: Consensus is not infallible and can evolve with new evidence.
4) The Pragmatic Theory
Truth is what is useful or beneficial in practice.
Propositions are true if they work satisfactorily or help achieve goals.
Means-end orientation: meaning is in practical consequences, not merely theory.
Example: belief in religion may be true for an individual if it helps them become a better person; truth is evaluated by usefulness.
Overall takeaway on the theories of truth:
No single theory is universally superior.
Each theory is suitable for different kinds of truth, and each has flaws.
The purpose of presenting these theories is to show that we use different standards for truth depending on the context.
Additional Notes and References
The content draws on multiple sources including:
Demeterio III, F.P.A. (2001) The Fallacies, Metro Manila: Department of Philosophy and HRD, San Beda College.
Frontlearners: Introduction to the Philosophy of the Human Person (DOST–STARBOOKS).
General reminder: Use awareness of these fallacies as tools for critical thinking, argument evaluation, and ethical reasoning in real-world contexts such as media literacy, politics, and academia.
Practical Takeaways
When evaluating arguments, check for:
Structural validity (for deductive forms) and inductive strength (for generalizations).
Any use of linguistic manipulation, emotional appeals, or psychological tactics that bypass rational analysis.
Whether conclusions depend on a single fallacious move (e.g., hasty generalization, false dilemma) or a chain of moves (e.g., slippery slope, red herring).
Use the four theories of truth as lenses to assess claims in different domains (science, philosophy, policy, everyday reasoning).
Quick Reference: Selected Examples (Condensed)
Hasty Generalization: 4 respondents imply universal conclusion about all students.
Four-Term Fallacy: Dogs, Animals, Cats, Mammals used incongruently.
Faulty Exclusion: Excluding relevant factors to falsely isolate a cause.
Undistributed Middle: Middle term not distributed, undermining inference.
Illicit Distribution: Conclusion uses a distributed term not justified by premise.
False Dilemma: Only two extreme options presented.
Beard Argument: Gradual escalation used to blur differences.
Strawman: Misrepresentation to attack a weaker version.
Slippery Slope: One action leads to inevitable extreme consequences.
Red Herring: Diverting from main issue to a related but irrelevant issue.
Begging the Question: Circular reasoning without external justification.
Appeal to Ignorance: Lack of evidence is used as proof of truth or falsehood.
Post Hoc: Chronology used to infer causation without evidence.
Ad Hominem: Attacking the person rather than the argument.
Lifting Out of Context: Distorting meaning by removing surrounding text.
Composition vs Division: Whole vs part reasoning errors.
False/Mutual Dilemmas: Over-simplified choices ignore nuance.