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logic


  4  definitions  found 
 
  From  Webster's  Revised  Unabridged  Dictionary  (1913)  [web1913]: 
 
  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; 
  correct  reasoning. 
 
  From  WordNet  r  1.6  [wn]: 
 
  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}] 
 
  From  The  Free  On-line  Dictionary  of  Computing  (13  Mar  01)  [foldoc]: 
 
  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  {proof}s  in  terms  of  symbols 
  representing  {proposition}s  and  {logical  connective}s.  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 
  {quantifier}s  and  symbols  standing  for  {predicate}s  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  {proof}s  are  made  in  terms  of  symbols 
  representing  {proposition}s  and  {logical  connective}s.  The 
  meanings  of  these  begin  with  a  set  of  rules  or  {primitive}s 
  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 
  value}s:  AND  OR  NOT  and  combinations  thereof.  {Predicate 
  logic}  extends  this  with  {existential  quantifier}s  and 
  {universal  quantifier}s  which  introduce  {bound  variable}s 
  ranging  over  {finite}  sets;  the  {predicate}  itself  takes  on 
  only  the  values  true  and  false.  Deduction  describes  how  we 
  may  proceed  from  valid  {premise}s  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) 
 
 
 
  From  THE  DEVIL'S  DICTIONARY  ((C)1911  Released  April  15  1993)  [devils]: 
 
  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. 
 
 




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