circularity
circularity — noun
1. a problem in an argument or explanation in which the conclusion that you want to
a problem in an argument or explanation in which the conclusion that you want to prove is already present in the starting point, so no real evidence or new information is introduced
The judge saw a clear circularity in the lawyer's argument — it proved nothing new.
uncountable: circularity in [someone's] argument
Yasmin's essay pointed out that the theory's circularity made it impossible to test.
pattern: [possessive] circularity
Professor Hugo showed how the journalist's argument suffered from circularity — it used the claim itself as proof of the claim.
Elena noticed the circularity in the committee's report, which assumed the very policy it was supposed to evaluate.
To avoid circularity, Chiara based her argument on test results rather than on the assumption she was trying to prove.
- tautology
more specific — a statement that is true by definition but says nothing new; circularity is the broader structure of which tautology can be a part
- vicious circle
more concrete — refers to a chain of events where solving one problem creates another, rather than a logical flaw in reasoning
- self-reference
broader — not necessarily flawed; self-reference can be valid (e.g. 'This sentence is in English.') while circularity is always a defect
- linear reasoning
a style of argument that moves step by step towards a conclusion without returning to the starting point
- empirical support
evidence drawn from observation or experiment, which is the opposite of the self-contained nature of a circular argument
用法筆記
Frequently used in academic or formal writing about logic, philosophy, and argumentation. The noun is uncountable in ordinary use; in very technical or logic-specific writing the countable form 'a circularity' is sometimes used to refer to one specific instance of the flaw.
常見錯誤
2. a measure of how completely round something is; how closely an object's shape ma
a measure of how completely round something is; how closely an object's shape matches that of a perfect circle
The engineer checked the circularity of each metal ring before using it in the assembly.
pattern: check/test/measure the circularity of [object]
Kenji used a digital gauge to measure the circularity of the ceramic bowl.
The quality inspector checked the circularity of each pipe flange before signing off on the shipment.
Nila was impressed by the near-perfect circularity of the handmade plates.
Laser tools can test a ball bearing's circularity to within a thousandth of a millimetre.
- roundness
less technical and more general; 'roundness' can describe shapes that are not perfectly circular (e.g. an egg), while 'circularity' usually implies an exact circle
- rotundity
formal or humorous — more often used for three-dimensional roundness or plumpness, not engineering precision
- sphericity
for three-dimensional objects (balls/spheres), not for flat circles
- distortion
a deviation from the intended round shape, often used in manufacturing
- ellipticity
the quality of being oval rather than circular, used in geometry and astronomy
用法筆記
Common in engineering, manufacturing, and technical drawing. The noun can be used with a precise measurement: 'a circularity of 0.02 mm' means the object deviates from a perfect circle by at most 0.02 millimetres.