valid
VAL-id
/ˈvæl.ɪd/
Describing an argument whose structure guarantees that if its premises are true, its conclusion must be true.
Validity is purely structural; an argument can be valid even if its premises are completely absurd (e.g., 'All pigs fly; Barnaby is a pig; therefore Barnaby flies' is valid, but unsound).
The story behind the word. From Latin 'validus' ('strong, effective'), derived from 'valere' ('to be strong'). A valid argument has internal strength—its structural skeleton holds firm regardless of external facts.
Word relationships
- cogent: Cogent implies persuasive power to human readers, whereas valid refers strictly to formal logical structure.
- invalid: Invalid means the conclusion does not follow logically from the premises.
Commonly confused with
- sound: Validity refers only to correct structural logic, whereas soundness requires both valid logic and factual truth.
Word family
- validity (noun): The quality of being logically valid.
- validate (verb): To confirm or prove the validity of something.
Collocations
- valid argument
- valid inference
- logically valid
- valid point
Idioms & expressions
- null and void
Example sentences
- "The deduction was valid because the conclusion followed directly from the premises, even though the starting assumption was flawed." Logical Evaluation
- "A valid inference is one in which it is impossible for the conclusion to be false if the premises are true." Academic Discourse
Memory hook
VAL-id arguments possess structural VAL-ue and strength. Unbreakable logical structure.
When not to use
Do not confuse 'valid' with 'true'. Statements are true or false; arguments are valid or invalid.
Fun facts
- The Latin root 'valere' gives us 'valor', 'value', and 'validate' as well as 'valid'.
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