What does ampliative mean?
Ampliative is an adjective from logic and philosophy describing reasoning whose conclusions contain more information than its premises do. When we reason deductively, the conclusion is already implicit in what we started with; ampliative inference, by contrast, genuinely extends our knowledge, reaching claims that go beyond anything the premises strictly guarantee. Induction is the classic example: observing many white swans supports, but does not entail, the conclusion that all swans are white. The term was used by medieval logicians under the related notion of ampliation and was later taken up by the American philosopher Charles Sanders Peirce, for whom ampliative reasoning was the engine of all real inquiry and scientific progress. Because it marks the crucial difference between merely unpacking what we know and actually learning something new, ampliative remains a valuable term in discussions of induction, probability, and the philosophy of science, though it seldom appears outside academic writing.
adjectiveOf an inference or argument: extending to conclusions that go beyond what is contained in the premises, thereby adding new information rather than merely unpacking it.
- (Logic) Of an inference, judgment, or argument: extending beyond the content of its premises so as to yield new information, as opposed to merely explicating what is already contained in them.
"Induction is an ampliative form of reasoning because its conclusions reach beyond the evidence given in the premises."
"Because no finite set of observations guarantees a universal law, all inductive science rests on ampliative reasoning."
"The philosopher distinguished mere deduction from ampliative argument, insisting that only the latter could enlarge our knowledge of the world."
Coined in medieval logic and revived by Charles Peirce, 'ampliative' names the kind of thinking that actually teaches you something new — every scientific discovery is ampliative.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of ampliative
Ampliative derives from the Latin verb ampliare, meaning 'to enlarge', formed on amplus ('large' or 'spacious'), the same root that gives English ample, amplify, amplitude, and amplification. It entered English through the tradition of scholastic logic, where the noun ampliation named the widening of a term's range in a proposition, with the adjective attested from around the sixteenth century. Charles Sanders Peirce gave the word its modern currency in nineteenth-century American philosophy, using 'ampliative' to characterise any inference that adds to our knowledge. Its cognates share the Latin enlarging sense rather than any logical one.
Related word forms
How ampliative is actually used
A technical term used almost exclusively in philosophy, formal logic, and epistemology; rare in everyday speech. It carries no emotional connotation but signals scholarly register.
Easily confused with ampliative
Explicative (or explicative) inference merely makes explicit what is already contained in the premises, whereas ampliative inference adds genuinely new information.
Ambiguous means open to multiple interpretations, while ampliative describes reasoning that extends beyond its given premises; the two are unrelated in meaning despite a superficial sound resemblance.