Basic limiting principle¶

A usually tacit general assumption that bounds what an explanatory framework treats as possible or knowable.

Version: v1 · 2026-09-28 · History
Domain-specific #: 8126
Domain group: Humanities
Origin domain: Philosophy
Subdomains: Philosophy of Science, Epistemology → Philosophy

Core Idea¶

C. D. Broad called a usually unquestioned, general constraint on what can happen or be known a basic limiting principle. Such a principle functions as a boundary of an explanatory framework: for example, a background assumption about causal order or how one person can know another's experience. Its role is not that it has been proven beyond revision, but that it is normally presupposed when ordinary and scientific accounts are constructed.

Broad proposed identifying the principle and then examining an apparently conflicting report in stages: did the event occur as described, could chance or a familiar cause explain it, and would a new but still compatible mechanism suffice? Only a robust unresolved case would pressure the framework itself. His historical card-guessing example was later discredited by evidence of data manipulation. That failure reinforces the distinction between an analytic tool for locating assumptions and evidence that an extraordinary counterexample exists.

How would you explain it like I'm…

The Rules We Don't Question

Some rules we almost never question, like 'you can't know what someone else is thinking unless they show or tell you.' A thinker named C. D. Broad called these basic limiting principles. When a story seems to break one, you check carefully: did it really happen, could it be luck or an ordinary explanation, or could a new but normal reason explain it? Only if nothing else works would you start questioning the rule itself.

Taken-for-Granted Big Rules

A basic limiting principle is a big background rule about what can happen or what can be known, one that almost everyone takes for granted, such as 'causes come before their effects.' The philosopher C. D. Broad gave these rules that name. They aren't proven forever; they're just the edges we build our everyday and scientific explanations inside. When someone reports something that seems to break such a rule, Broad suggested checking step by step: did it really happen as described, could chance or a familiar cause explain it, and could a new explanation fit within the rules? Only a strong case that survives all those checks should make us rethink the rule.

Presupposed Framework Constraints

C. D. Broad used 'basic limiting principle' for a general, usually unquestioned constraint on what can happen or be known, such as an assumption about causal order or about how one person can know another's experiences. These principles act as boundaries of an explanatory framework: not because they've been proven beyond revision, but because ordinary and scientific explanations normally presuppose them. Broad proposed a staged way of handling a report that seems to violate one: first, did the event actually occur as described; second, could chance or a familiar cause explain it; third, would a new mechanism that is still compatible with the framework be enough? Only a robust case left unresolved after all this would put pressure on the framework itself. Broad's own historical card-guessing example was later discredited when evidence of data manipulation emerged, which highlights the difference between a tool for locating assumptions and evidence that an extraordinary counterexample exists.

A basic limiting principle, in C. D. Broad's usage, is a general and usually unquestioned constraint on what can happen or be known, functioning as a boundary of an explanatory framework; examples include background assumptions about causal order or about how one person can know another's experience. Its status is not that of a proven, unrevisable truth but of a presupposition built into ordinary and scientific accounts. Broad's method was first to identify the principle and then to examine an apparently conflicting report in stages: whether the event occurred as described, whether chance or a familiar cause explains it, and whether a new mechanism compatible with the principle suffices. Only a robust, unresolved case would then pressure the framework itself. His historical card-guessing example was later discredited by evidence of data manipulation, a failure that reinforces the distinction between the principle as an analytic tool for locating assumptions and evidence that an extraordinary counterexample actually exists.

Scope of Application¶

This is Broad's philosophical term for background limits, not an endorsement of purported extraordinary counterexamples.

Philosophy of science. Expose tacit constraints in explanatory frameworks.
Epistemology. Ask what routes to information a theory permits.
Historical analysis. Read Broad's causal and mind–brain assumptions in context.
Evidence assessment. Separate apparent conceptual conflict from reliability of a reported observation.

Clarity¶

Broad used basic limiting principle for a deep, usually tacit assumption about what can happen or be known. An apparent violation must first be checked for error, chance, ordinary causes, and evidence quality. His famous card-guessing case was later discredited, so it illustrates his method's historical use, not a genuine exception.

Manages Complexity¶

A framework can hide its own limits by treating them as obvious. Naming the assumption clarifies what a purported anomaly would actually challenge. Yet an apparent violation may be an error, fraud, chance, or a new mechanism compatible with the old framework; philosophical revision is a much later inference.

Abstract Reasoning¶

State the assumed limit, specify what would conflict with it, verify the reported event and competing explanations, and distinguish a real conceptual challenge from weak or manipulated evidence.

Knowledge Transfer¶

Other fields also rely on tacit constraints, but literal use of Broad's term concerns broad metaphysical or epistemic limits. A local statistical model assumption can be analogous without being a basic limiting principle in his historical sense. The method of surfacing assumptions transfers more widely than the exact list he proposed.

Relationships to Other Abstractions¶

Current abstraction Basic limiting principle Domain-specific

Parents (1) — more general patterns this builds on

Basic limiting principle is a kind of Assumption Prime

Broad's usually tacit possibility limit is a load-bearing proposition held in explanatory reasoning.

Hierarchy path (1) — routes to 1 parentless root

Basic limiting principle → Assumption → Epistemic Mode Of A Proposition

Neighborhood in Abstraction Space¶

Basic limiting principle sits in a crowded region of the domain-specific corpus (38^th percentile for distinctiveness): several abstractions share nearly its structure, so a description that fits it tends to fit its neighbors too.

Family — Critical & Continental Social Theory (18 abstractions)

Nearest neighbors

Computed from structural-signature embeddings · 2026-10-08