- a process of reasoning in which a conclusion follows necessarily from the premises presented, so that the conclusion cannot be false if the premises are true.
- a conclusion reached by this process.Compare induction(def 4).
- deductible clause,
- deduction theorem,
Origin of deduction
Examples from the Web for deduction
True, making an Item 24 deduction requires me to “Attach Form 2106.”Up to a Point: I Do My Own Taxes With No Help, Except From a Couple of Bloody Marys|P. J. O’Rourke|April 15, 2014|DAILY BEAST
But it would represent a deduction of nearly 20 percent from fiscal 2012.The Sequester Is Proof that Washington Thinks We Are All Idiots|Daniel Gross|March 14, 2013|DAILY BEAST
Master of deduction Sherlock refuses to put together the evidence that his girlfriend Alyssa is cheating on him.
National Review's editors would rather end the deduction for state and local taxes than increase rates.
The deduction for state and local taxes does not much interest Texans.
The deduction cannot be legitimately drawn until the possibility of any other cause of specific modification has been excluded.Darwin, and After Darwin, Volume II (of 3)|George John Romanes
Why, Mary Louise, in this deduction we have all the necessary elements of the usual crime.Mary Louise Solves a Mystery|L. Frank Baum
We do criticise individual cases very freely, yet make no deduction from our own wide observations.Concerning Children|Charlotte Perkins Gilman
They are finding out things by experimentation or thought; by induction or deduction.A Librarian's Open Shelf|Arthur E. Bostwick
From this the deduction is easy that greatness depends on the possession of formidable military power.Armageddon--And After|W. L. Courtney
- the process of reasoning typical of mathematics and logic, whose conclusions follow necessarily from their premises
- an argument of this type
- the conclusion of such an argument
- a systematic method of deriving conclusions that cannot be false when the premises are true, esp one amenable to formalization and study by the science of logic
- an argument of this typeCompare induction (def. 4)
early 15c., "action of deducting," from Middle French déduction or directly from Latin deductionem (nominative deductio), noun of action from past participle stem of deducere (see deduce). Meaning "that which is deducted" is from 1540s. As a term in logic, from Late Latin use of deductio as a loan-translation of Greek apagoge.
The logical processes known as deduction and induction work in opposite ways. In deduction general principles are applied to specific instances. Thus, using a mathematical formula to figure the volume of air that can be contained in a gymnasium is applying deduction. Similarly, applying a law of physics to predict the outcome of an experiment is reasoning by deduction. By contrast, induction makes generalizations based on a number of specific instances. The observation of hundreds of examples in which a certain chemical kills plants might prompt the inductive conclusion that the chemical is toxic to all plants. Inductive generalizations are often revised as more examples are studied and more facts are known. If certain plants that have not been tested turn out to be unaffected by the chemical, the conclusion about the chemical's toxicity must be revised or restricted. In this way, an inductive generalization is much like a hypothesis.
A process of reasoning that moves from the general to the specific. (Compare induction.)
A cost or expense subtracted from revenue, usually for tax purposes.