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Bulverism

Also Known As: Psychogenetic Fallacy Assumed Refutation
Informal Fallacy ID: bulverism

Definition

Bulverism, coined by C.S. Lewis, occurs when someone assumes an opponent's argument is wrong and then explains why the opponent came to hold such a flawed view, typically by attributing it to psychological, social, or ideological causes. It skips the step of actually demonstrating that the argument is wrong. It combines an assumed refutation with a psychologizing explanation.

Examples

"You only support universal healthcare because you grew up poor. Your economic background makes you unable to think rationally about this."

A male colleague dismisses a female coworker's concerns about gender pay gaps: 'You only believe the pay gap is real because you're a woman. Your personal feelings are clouding your judgment on this issue.'

During an online debate about immigration policy, one user writes: 'You only oppose stricter border controls because you're an immigrant yourself. Of course you'd think that — you're not capable of being objective about it.'

Formal Logic Pattern
FOL Pattern
The First-Order Logic formula representing this reasoning pattern's logical structure.
FOL (First-Order Logic) uses quantifiers (∀ = for all, ∃ = there exists), connectives (∧ = and, ∨ = or, ⇒ = implies, ¬ = not), and predicates to capture the essential form of a reasoning pattern. For example, the Ad Hominem fallacy: Person(x) ∧ HasFlaw(x) ⇒ Invalid(Claim(x)). These patterns allow automated verification of logical validity.

Wrong(x) ∧ Motive(x, M) ⇒ Explains(M, Wrong(x))
Formal Verification:
Formal Verification
Checks whether a reasoning pattern is logically valid or invalid using an automated theorem prover.
Formal verification uses an SMT (Satisfiability Modulo Theories) solver — specifically Z3 — to mathematically check whether an argument's logical structure is valid. Each reasoning pattern is translated into First-Order Logic and tested: Can the premises be true while the conclusion is false? If yes, it's formally invalid. If no, it's formally valid. Many real-world patterns (analogies, heuristics) cannot be fully captured in formal logic — these are marked as not formally decidable, which doesn't mean they're wrong.
Not formally decidable

Verification Steps
Verification Steps
Binary yes/no questions that an AI must answer to detect a reasoning pattern in a text.
Each of the 452 aspects has verification steps — simple yes/no questions designed to systematically detect whether a pattern appears in a text. For ad hominem: "Does the argument attack a person rather than their claim?" For false dichotomy: "Are only two options presented when more exist?" This ensures consistent, reproducible analysis.

Binary (yes/no) questions an LLM must answer to identify this aspect:

  1. 1

    Does the arguer assume the opponent is wrong without proving it?

    Type: binary
  2. 2

    Does the arguer explain the opponent's error based on their identity, motives, or psychology?

    Type: binary
  3. 3

    Is the causal explanation used as a substitute for actually refuting the claim?

    Type: binary
Deep Dive
The expandable detail section on each aspect page with examples, psychology, and counter-strategies.
The Deep Dive section provides in-depth information about each aspect: a real-world example showing the pattern in action, an explanation of why it works psychologically, practical advice on how to counter it, alternative names, and links to related aspects.

Hierarchical Context