# logic

(redirected from*logical expression*)

Also found in: Thesaurus, Medical, Encyclopedia.

## log·ic

(lŏj′ĭk)*n.*

**1.**The study of principles of reasoning, especially of the structure of propositions as distinguished from their content, and of method and validity in deductive reasoning.

**2.**

**a.**A system of reasoning: Aristotle's logic.

**b.**A mode of reasoning: By that logic, we should sell the company tomorrow.

**c.**The formal, guiding principles of a discipline, school, or science.

**3.**Valid reasoning: Your paper lacks the logic to prove your thesis.

**4.**The relationship between elements and between an element and the whole in a set of objects, individuals, principles, or events: There's a certain logic to the motion of rush-hour traffic.

**5.**

*Computers*

**a.**The nonarithmetic operations performed by a computer, such as sorting, comparing, and matching, that involve yes-no decisions.

**b.**Computer circuitry.

**c.**Graphic representation of computer circuitry.

[Middle English, from Old French

`logique`, from Latin`logica`, from Greek`logikē (tekhnē)`,*(art) of reasoning, logic*, feminine of`logikos`,*of reasoning*, from`logos`,*reason*; see`leg-`in the Appendix of Indo-European roots.]## logic

(ˈlɒdʒɪk)*n*

**1.**(Logic) the branch of philosophy concerned with analysing the patterns of reasoning by which a conclusion is properly drawn from a set of premises, without reference to meaning or context. See also formal logic, deduction

^{4}, induction

^{4}

**2.**(Logic) any particular formal system in which are defined axioms and rules of inference. Compare formal system, formal language

**3.**the system and principles of reasoning used in a specific field of study

**4.**a particular method of argument or reasoning

**5.**force or effectiveness in argument or dispute

**6.**reasoned thought or argument, as distinguished from irrationality

**7.**the relationship and interdependence of a series of events, facts, etc

**8.**(Logic)

**chop logic**to use excessively subtle or involved logic or argument

**9.**(Computer Science)

*electronics*

*computing*

**a.**the principles underlying the units in a computer system that perform arithmetical and logical operations. See also logic circuit

**b.**(

*as modifier*): a logic element.

[C14: from Old French

*logique*from Medieval Latin*logica*(neuter plural, treated in Medieval Latin as feminine singular), from Greek*logikos*concerning speech or reasoning]## log•ic

(ˈlɒdʒ ɪk)*n.*

**1.**the science that investigates the principles governing correct or reliable inference.

**3.**a particular method of reasoning or argumentation.

**4.**the system or principles of reasoning applicable to any branch of knowledge or study.

**5.**reason or sound judgment, as in utterances or actions.

**6.**the consistency to be discerned in a work of art, system, etc.

**7.**any connection between facts that seems reasonable or inevitable.

**8.**

**a.**the arrangement of circuitry in a computer.

**b.**a circuit or circuits designed to perform functions defined in terms of mathematical logic.

[1325–75; Middle English

*logik*< Latin*logica,*n. use of neuter pl. of Greek*logikós*of speech or reason. See logos, -ic]**log′ic•less,**

*adj.*

## log·ic

(lŏj′ĭk) The study of the principles of reasoning.

## Logic

the process of reasoning from effect to cause, based upon observation.

**1.**the method of

*a priori*reasoning, i.e., deductive reasoning, from cause to effect or from the general to the particular.

**2.**an

*a priori*principle.

a mnemonic word to represent a syllogistic argument in the first figure, in which there are two universal affirmative premises and a universal affirmative conclusion.

a mnemonic word to represent a syllogistic argument in the fourth figure, in which there are two universal affirmative premises and a particular affirmative conclusion.

a mnemonic word to represent a syllogistic argument in the second figure, in which there is one universal affirmative and one particular negative premise and a particular negative conclusion.

a mnemonic word to represent a syllogistic argument in the third figure, in which there is one particular negative and one universal affirmative premise and a particular negative conclusion.

a mnemonic word to represent a syllogistic argument in the second figure, in which there is one universal affirmative and one universal negative premise and a universal negative conclusion.

a mnemonic word to represent a syllogistic argument in the first figure, in which there is one universal negative and one universal affirmative premise and a universal negative conclusion.

a mnemonic word to represent a syllogistic argument in the second figure, in which there is one universal negative and one universal affirmative premise and a universal negative conclusion.

a mnemonic word to represent a syllogistic argument in the third figure, in which there are two universal affirmative premises and a particular affirmative conclusion.

a mnemonic word to represent a syllogistic argument in the first figure, in which there is one universal affirmative and one particular affirmative premise and a particular affirmative conclusion.

a mnemonic word to represent a syllogistic argument in the third figure, in which there is one universal affirmative and one particular affirmative premise and a particular affirmative conclusion.

**1.**an expression that has to be defined in terms of a previously defined expression.

**2.**anything that has to be defined. —

**definienda**,

*n., pl*.

Dimatis.

a mnemonic word to represent a syllogistic argument in the fourth figure, in which there is one universal affirmative and one affirmative premise and a particular affirmative conclusion. Also called

**Dimaris**.a mnemonic word to represent a syllogistic argument in the third figure, in which there is one particular affirmative and one universal affirmative premise and a particular affirmative conclusion.

a syllogistic argument that refutes a proposition by proving the direct opposite of its conclusion. —

**elenchic, elenctic**,*adj*.a syllogism in which the truth of one of the premises is confirmed by an annexed proposition

*(prosyllogism)*, thus resulting in the formation of a compound argument. See also**prosyllogism**.equality between two or more propositions, as when two propositions have the same meaning but are expressed differently. See also agreement.

a mnemonic word to represent a syllogistic argument in the third figure, in which there is one universal negative and one universal affirmative premise and a particular negative conclusion.

a mnemonic word to represent a syllogistic argument in the first figure, in which there is one universal negative and one particular affirmative premise and a particular negative conclusion.

a mnemonic word to represent a syllogistic argument in the third figure, in which there is one universal negative and one particular affirmative premise and a particular negative conclusion. Also

**Ferison**.Feriso.

a mnemonic word to represent a syllogistic argument in the fourth figure, in which there is one universal negative and one universal affirmative premise and a particular negative conclusion.

a mnemonic word to represent a syllogistic argument in the second figure, in which there is one universal negative and one particular affirmative premise and a particular negative conclusion.

a mnemonic word to represent a syllogistic argument in the fourth figure, in which there is one universal negative and one particular affirmative premise and a particular negative conclusion.

the metaphysics or metaphysical aspects of logic. —

**metalogical**,*adj*.a division of logic devoted to the application of reasoning to science and philosophy. See also classification; order and disorder. —

**methodological**,*adj*.a multiple dilemma or one with many equally unacceptable alternatives; a difficult predicament.

a syllogism connected with another in such a way that the conclusion of the first is the premise of the one following.

the form or character of a syllogism.

an elliptical series of syllogism, in which the premises are so arranged that the predicate of the first is the subject of the next, continuing thus until the subject of the first is united with the predicate of the last. —

**soritical, soritic**,*adj*.a form of reasoning in which two propositions or premises are stated and a logical conclusion is drawn from them. Each premise has the subject-predicate form, and each shares a common element called the

*middle term*.the principles or practice of synthesis or synthetic methods or techniques, i.e., the process of deductive reasoning, as from cause to effect, from the simple elements to the complex whole, etc.

ThesaurusAntonymsRelated WordsSynonyms

**Legend:**Switch to new thesaurus

Noun | 1. | logic - the branch of philosophy that analyzes inferenceconsistency - (logic) an attribute of a logical system that is so constituted that none of the propositions deducible from the axioms contradict one another completeness - (logic) an attribute of a logical system that is so constituted that a contradiction arises if any proposition is introduced that cannot be derived from the axioms of the system corollary - (logic) an inference that follows directly from the proof of another proposition non sequitur - (logic) a conclusion that does not follow from the premises arity - the number of arguments that a function can take philosophy - the rational investigation of questions about existence and knowledge and ethics modal logic - the logical study of necessity and possibility logical quantifier, quantifier - (logic) a word (such as `some' or `all' or `no') that binds the variables in a logical proposition subject - (logic) the first term of a proposition predicate - (logic) what is predicated of the subject of a proposition; the second term in a proposition is predicated of the first term by means of the copula; "`Socrates is a man' predicates manhood of Socrates" proof - a formal series of statements showing that if one thing is true something else necessarily follows from it paradox - (logic) a statement that contradicts itself; "`I always lie' is a paradox because if it is true it must be false" postulation, predication - (logic) a declaration of something self-evident; something that can be assumed as the basis for argument explanandum, explicandum - (logic) a statement of something (a fact or thing or expression) to be explained explanans - (logic) statements that explain the explicandum; the explanatory premises proposition - (logic) a statement that affirms or denies something and is either true or false particular proposition, particular - (logic) a proposition that asserts something about some (but not all) members of a class universal proposition, universal - (logic) a proposition that asserts something of all members of a class negation - (logic) a proposition that is true if and only if another proposition is false posit, postulate - (logic) a proposition that is accepted as true in order to provide a basis for logical reasoning axiom - (logic) a proposition that is not susceptible of proof or disproof; its truth is assumed to be self-evident tautology - (logic) a statement that is necessarily true; "the statement `he is brave or he is not brave' is a tautology" contradiction in terms, contradiction - (logic) a statement that is necessarily false; "the statement `he is brave and he is not brave' is a contradiction" logic operation, logical operation - an operation that follows the rules of symbolic logic logical relation - a relation between propositions transitivity - (logic and mathematics) a relation between three elements such that if it holds between the first and second and it also holds between the second and third it must necessarily hold between the first and third reflexiveness, reflexivity - (logic and mathematics) a relation such that it holds between an element and itself quantify - use as a quantifier presuppose, suppose - require as a necessary antecedent or precondition; "This step presupposes two prior ones" analytical, analytic - of a proposition that is necessarily true independent of fact or experience; "`all spinsters are unmarried' is an analytic proposition" synthetical, synthetic - of a proposition whose truth value is determined by observation or facts; "`all men are arrogant' is a synthetic proposition" inductive - of reasoning; proceeding from particular facts to a general conclusion; "inductive reasoning" nonmonotonic - not monotonic categorematic - of a term or phrase capable of standing as the subject or (especially) the predicate of a proposition syncategorematic - of a term that cannot stand as the subject or (especially) the predicate of a proposition but must be used in conjunction with other terms; "`or' is a syncategorematic term" scopal - of or relating to scope; "scopal dependency" |

2. | logic - reasoned and reasonable judgment; "it made a certain kind of logic"common sense, good sense, gumption, horse sense, mother wit, sense - sound practical judgment; "Common sense is not so common"; "he hasn't got the sense God gave little green apples"; "fortunately she had the good sense to run away" | |

3. | logic - the principles that guide reasoning within a given field or situation; "economic logic requires it"; "by the logic of war"principle - a basic truth or law or assumption; "the principles of democracy" | |

4. | logic - the system of operations performed by a computer that underlies the machine's representation of logical operationssystem of rules, system - a complex of methods or rules governing behavior; "they have to operate under a system they oppose"; "that language has a complex system for indicating gender" computer science, computing - the branch of engineering science that studies (with the aid of computers) computable processes and structures | |

5. | logic - a system of reasoningsystem of rules, system - a complex of methods or rules governing behavior; "they have to operate under a system they oppose"; "that language has a complex system for indicating gender" Aristotelian logic - the syllogistic logic of Aristotle as developed by Boethius in the Middle Ages formal logic, mathematical logic, symbolic logic - any logical system that abstracts the form of statements away from their content in order to establish abstract criteria of consistency and validity extrapolate - gain knowledge of (an area not known or experienced) by extrapolating induce - reason or establish by induction negate, contradict - prove negative; show to be false elicit - derive by reason; "elicit a solution" |

## logic

*noun*

**1.**

**science of reasoning**, deduction, dialectics, argumentation, ratiocination, syllogistic reasoning Students learn philosophy and logic.

**2.**connection, rationale, coherence, relationship, link, chain of thought I don't follow the logic of your argument.

**3.**reason, reasoning, sense,

**good reason**, good sense, sound judgment The plan was based on sound commercial logic.

## logic

*noun*

**1.**Exact, valid, and rational reasoning:

**2.**What is sound or reasonable:

**rhyme or reason.**

*Idiom:*Translations

**عِلْم المَنْطِق**

**logika**

**logik**

**logiikka**

**logika**

**logika**

**rökfræîi; rökrétt hugsun**

**logika**

**loginis**

**logiškai**

**logiškas**

**loģika**

**logică**

**logika**

**logik**

## logic

(ˈlodʒik)*noun*

(the study and art of) reasoning correctly.

**ˈlogical**

*adjective*

(thinking or acting) according to the rules of logic. It is logical to assume that you will get a higher salary if you are promoted; She is always logical in her thinking.

**ˈlogically**

*adverb*

## logic

**, logical**

*a.*lógico-a, acertado-a.

Want to thank TFD for its existence? Tell a friend about us, add a link to this page, or visit the webmaster's page for free fun content.

Link to this page: