[W/K] :: logic

  Logic \Log"ic\, n. [OE. logike, F. logique, L. logica, logice,
     Gr. logikh` (sc. te`chnh), fr. logiko`s belonging to speaking
     or reason, fr. lo`gos speech, reason, le`gein to say, speak.
     See Legend.]
     1. The science or art of exact reasoning, or of pure and
        formal thought, or of the laws according to which the
        processes of pure thinking should be conducted; the
        science of the formation and application of general
        notions; the science of generalization, judgment,
        classification, reasoning, and systematic arrangement; the
        science of correct reasoning.
        [1913 Webster]
  
              Logic is the science of the laws of thought, as
              thought; that is, of the necessary conditions to
              which thought, considered in itself, is subject.
                                                    --Sir W.
                                                    Hamilton.
        [1913 Webster]
  
     Note: Logic is distinguished as pure and applied. "Pure logic
           is a science of the form, or of the formal laws, of
           thinking, and not of the matter. Applied logic teaches
           the application of the forms of thinking to those
           objects about which men do think." --Abp. Thomson.
           [1913 Webster]
  
     2. A treatise on logic; as, Mill's Logic.
        [1913 Webster]
  
     3. correct reasoning; as, I can't see any logic in his
        argument; also, sound judgment; as, the logic of surrender
        was uncontestable.
        [PJC]
  
     4. The path of reasoning used in any specific argument; as,
        his logic was irrefutable.
        [PJC]
  
     5. (Electronics, Computers) A function of an electrical
        circuit (called a gate) that mimics certain elementary
        binary logical operations on electrical signals, such as
        AND, OR, or NOT; as, a logic circuit; the arithmetic and
        logic unit.
        [PJC]

  logic
       n 1: the branch of philosophy that analyzes inference
       2: reasoned and reasonable judgment; "it made a certain kind of
          logic"
       3: the principles that guide reasoning within a given field or
          situation; "economic logic requires it"; "by the logic of
          war"
       4: a system of reasoning [syn: logical system, system of
          logic]

  72 Moby Thesaurus words for "logic":
     Aristotelian logic, Boolean algebra, Ramistic logic, admissibility,
     aesthetics, algebra of classes, algebra of relations, axiology,
     casuistry, common sense, cosmology, deduction, dialectic,
     dialectics, doctrine of inference, doctrine of terms,
     epistemological logic, epistemology, ethics, experimental logic,
     first philosophy, formal logic, gnosiology, good sense,
     intelligence, judiciousness, justifiability, justness, logicality,
     logicalness, logics, logistic, material logic, mathematical logic,
     mental philosophy, metaphysics, moral philosophy, ontology,
     phenomenology, philosophastry, philosophic doctrine,
     philosophic system, philosophic theory, philosophical inquiry,
     philosophical speculation, philosophy, plausibility, practicality,
     presence of mind, propositional calculus, psychological logic,
     psychologism, ratiocination, rationality, reason, reasonability,
     reasonableness, reasoning, school of philosophy, school of thought,
     science of being, sense, sensibleness, set theory, sophistry,
     sound sense, soundness, sweet reason, theory of beauty,
     theory of knowledge, value theory, wisdom
  
  

  logic
       
          1.  A branch of philosophy and
          mathematics that deals with the formal principles, methods and
          criteria of validity of inference, reasoning and
          knowledge.
       
          Logic is concerned with what is true and how we can know
          whether something is true.  This involves the formalisation of
          logical arguments and proofs in terms of symbols
          representing propositions and logical connectives.  The
          meanings of these logical connectives are expressed by a set
          of rules which are assumed to be self-evident.
       
          Boolean algebra deals with the basic operations of truth
          values: AND, OR, NOT and combinations thereof.  Predicate
          logic extends this with existential and universal
          quantifiers and symbols standing for predicates which may
          depend on variables.  The rules of natural deduction
          describe how we may proceed from valid premises to valid
          conclusions, where the premises and conclusions are
          expressions in predicate logic.
       
          Symbolic logic uses a meta-language concerned with truth,
          which may or may not have a corresponding expression in the
          world of objects called existance.  In symbolic logic,
          arguments and proofs are made in terms of symbols
          representing propositions and logical connectives.  The
          meanings of these begin with a set of rules or primitives
          which are assumed to be self-evident.  Fortunately, even from
          vague primitives, functions can be defined with precise
          meaning.
       
          Boolean logic deals with the basic operations of truth
          values: AND, OR, NOT and combinations thereof.  Predicate
          logic extends this with existential quantifiers and
          universal quantifiers which introduce bound variables
          ranging over finite sets; the predicate itself takes on
          only the values true and false.  Deduction describes how we
          may proceed from valid premises to valid conclusions, where
          these are expressions in predicate logic.
       
          Carnap used the phrase "rational reconstruction" to describe
          the logical analysis of thought.  Thus logic is less concerned
          with how thought does proceed, which is considered the realm
          of psychology, and more with how it should proceed to discover
          truth.  It is the touchstone of the results of thinking, but
          neither its regulator nor a motive for its practice.
       
          See also fuzzy logic, logic programming, arithmetic and logic unit,
          first-order logic,
       
          See also Boolean logic, fuzzy logic, logic programming,
          first-order logic, logic bomb, combinatory logic,
          higher-order logic, intuitionistic logic, equational
          logic, modal logic, linear logic, paradox.
       
          2.  Boolean logic circuits.
       
          See also arithmetic and logic unit, asynchronous logic,
          TTL.
       
          (1995-03-17)
       
       

  LOGIC, n.  The art of thinking and reasoning in strict accordance with
  the limitations and incapacities of the human misunderstanding.  The
  basic of logic is the syllogism, consisting of a major and a minor
  premise and a conclusion -- thus:
      _Major Premise_:  Sixty men can do a piece of work sixty times as
  quickly as one man.
      _Minor Premise_:  One man can dig a posthole in sixty seconds;
  therefore --
      _Conclusion_:  Sixty men can dig a posthole in one second.
      This may be called the syllogism arithmetical, in which, by
  combining logic and mathematics, we obtain a double certainty and are
  twice blessed.