equiprobabilism
C2academic/technical/philosophical
Definition
Meaning
the philosophical or statistical doctrine that all possibilities or hypotheses should be regarded as equally probable when no evidence distinguishes them.
In decision theory or moral theology, a principle where, when reasons for opposing choices are equally balanced, one is permitted to choose either option. In probability theory, it can refer to the assignment of equal prior probabilities to all simple events in the absence of prior information.
Linguistics
Semantic Notes
Primarily used in specialized fields: moral theology (Catholic casuistry), probability theory, decision theory. The core concept is the equality of epistemic probability under conditions of ignorance or symmetric evidence. It is a principle of reasoning under uncertainty, not a description of physical frequencies.
Dialectal Variation
British vs American Usage
Differences
Usage is equally rare in both variants; the term is field-specific, not region-specific. The spelling is consistent. The theological application may have slightly more historical currency in British academic writing due to older scholastic traditions, while the probability/decision theory application is equally present in American academia.
Connotations
In theology, can carry connotations of a specific, debated method of resolving moral doubt. In secular contexts, it is a neutral technical term for a principle of indifferent reasoning.
Frequency
Extremely low frequency. Likely encountered only in advanced academic texts in philosophy, theology, statistics, or game theory.
Vocabulary
Collocations
Grammar
Valency Patterns
[Subject] adheres to equiprobabilism.[Subject] applies equiprobabilism to [problem].The argument from equiprobabilism suggests that...Vocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Phrases
Idioms & Phrases
- “a toss-up (informal analogue for a binary choice)”
- “six of one, half a dozen of the other (informal analogue)”
Usage
Context Usage
Business
Virtually never used.
Academic
The primary context. 'The philosopher argued that, in the complete absence of evidence, equiprobabilism provides the only rational starting point for Bayesian updating.'
Everyday
Never used.
Technical
Used in statistical decision theory. 'The algorithm was initialised with an equiprobabilistic prior over all possible states.'
Examples
By Part of Speech
noun
British English
- The debate between equiprobabilism and probabiliorism was central to 18th-century casuistry.
- His thesis explored the mathematical foundations of equiprobabilism.
American English
- Equiprobabilism is often cited as the default rule for assigning priors in Bayesian statistics.
- Critics argue that equiprobabilism can lead to paradoxes if the set of possibilities is not carefully defined.
Examples
By CEFR Level
- Equiprobabilism is a very advanced concept from philosophy.
- If you have no information, equiprobabilism suggests treating all options as the same.
- The ethical dilemma was resolved by invoking a form of equiprobabilism, as the arguments for both courses of action seemed equally compelling.
- In the absence of any data, the researcher adopted an equiprobabilistic prior distribution.
- Modern critiques of the classical Principle of Indifference often trace its lineage back to the simpler formulations of equiprobabilism.
- The theologian's adherence to equiprobabilism led her to conclude that either charitable donation was permissible, given the equipoise of reasons.
Learning
Memory Aids
Mnemonic
Think: EQUI (equal) + PROBABILITY + ISM (doctrine) = the doctrine of equal probability.
Conceptual Metaphor
A LEVEL PLAYING FIELD for hypotheses; a BLANK SLATE of probability.
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Не переводите дословно как "равовероятность" (хотя это близко по смыслу). Стандартный философский/математический термин — "принцип безразличия" (principle of indifference). "Эквипробабилизм" — узкий историко-богословский термин.
Common Mistakes
- Misspelling: 'equiprobabalism' (incorrect vowel).
- Confusing it with 'probabilism' (a related but distinct doctrine).
- Using it to describe physical events known to be equally likely (e.g., a fair coin toss) rather than as an epistemic principle for handling ignorance.
Practice
Quiz
Equiprobabilism is LEAST likely to be discussed in which field?
FAQ
Frequently Asked Questions
Essentially, yes. 'Equiprobabilism' is a less common term, often used in specific historical or theological contexts, while 'Principle of Indifference' is the standard term in probability theory and philosophy of science.
In theory, yes, but it's a formal principle for reasoning under complete uncertainty. In everyday life, we rarely have truly zero information, so its strict application is limited. Informally, it's like flipping a coin when you can't decide.
The main criticism is that the 'set of possibilities' can be described in different ways, leading to contradictory probability assignments (e.g., Bertrand's paradoxes). It requires a careful specification of the basic, symmetric alternatives.
It is primarily a philosophical and logical concept that informs scientific (particularly statistical) reasoning. It provides a normative rule for how one *should* assign probabilities in the absence of evidence, which is a foundational question in epistemology and the philosophy of probability.