Aristotle彭秀芬384-322BCBorninStagira,inThrace,nearMacedonia.SonofNicomachus,prominentphysicianofthekingofMacedonAristotlewaseducatedasamemberofthearistocracyPlato’sStudentAtage17,AristotlewassenttostudywithPlatoattheAcademy.HebecamePlato’smostimportantstudent,remainingattheAcademy20years,untilPlato’sdeath.•Inhisformeryears,hedevotedhimselftoPlatonism.ButafterPlato’sdeath,Aristotleimmersedhimselfinempiricalstudiesandshiftedtoempiricism(经验论).•“Platoisdeartome,butdearerstillistruth.”(吾爱吾师,吾更爱真理)Aristotlebecamearoyaltutor.•AristotletutoredPhillip’sson,Alexander,for5yearsuntilPhillipdiedandAlexanderassumedthethrone.•AlexandertheGreatwentontoconquermuchofthenearbyworld•AristotleencouragedAlexandertowardeasternconquestandhisattitudetowardsPersiawasunabashedlyethnocentric.•E.g.:hecounselsAlexandertobealeadertotheGreeksandadespot(专制者)tothebarbarians,tolookaftertheformerasafterfriendsandrelatives,andtodealwiththelatteraswithbeastsorplants.•In335BC,AristotlereturnedtoAthensandestablishedhisownschool,incompetitionwiththeAcademy.TheLyceumAristotle’sworks•WhatwehaveasAristotle’sworksareabout30closelywritten,terse,treatisesonafullrangeofphilosophicalandscientifictopics.•Thesemayhavebeenhismorninglectures,orevenstudent’snotesonthoselectures.AnEncyclopedicThinkerPhysicalscience:anatomy,astronomy,embryology,geography,meteorology,physics,zoology;Philosophy:aesthetics,ethics,government,metaphysics,politics,economics,rhetoricandtheology.Hisworkslaidthegroundworkforthesystematicdevelopmentofphilosophyandthebasicframeworkfortheunderstandingofnature.Empiricism(经验论)•Aristotlegroundsallknowledgeonexperience.–ThisisunlikePlatoforwhomknowledgecameonlywhenthephilosopherescapedfromtheworldofsenseperception,whichcouldmislead.–Reality,forAristotle,wastheworldaroundus,nottheobjectsofthemind,whichcouldbejustfantasy.Aristotle&PlatoAbasicdivisioninhowtheworldisunderstood:•Plato–(pointingup)trueknowledgecomesfromcontemplatingtheabstractideas.•Aristotle–(pointingdown)trueknowledgecomesfromcloseexaminationoftheworldaround.PlatoandAristotlefromRaphael’sSchoolofAthens.Logic•WiththePriorAnalytics,Aristotleiscreditedwiththeearlieststudyofformallogic,andhisconceptionofitwasthedominantformofWesternlogicuntil19thcenturyadvancesinmathematicallogic.Syllogisms(三段论)•ThekeycomponentofAristotelianlogicisthesyllogism.•Typicalformat:–Majorpremise–ageneraltruth,orobservation–Minorpremise–aparticularfact,orspecificobservation–Conclusion–aninferenceimpliedbythetwopremisestogether•Theclassicexampleofthesyllogism:–Majorpremise:Allmenaremortal.–Minorpremise:Socratesisaman.–Conclusion:Socratesismortal.•Inotherwords,whatappliestoallmembersofagroupappliestoeachandeverymember.Aristotle’sCosmos•Classification:Therearetwodifferentpartsoftheworld.–Sub-lunarWorld:thereistheworldallaround,wherethingscomeandgo;areborn,live,anddie;andmotionsstartandstop.–Thereistheworldupinthesky,wherethingshappenoverandoveragain:thesunrisesandsets,theseasonsreoccur,theplanetsrepeatcycles.TheMaterialoftheWorld•AristotleacceptedthepopularfourelementsofEmpedoclesasthematerialofthesub-lunarworld:–Earth,Air,Fire,Water.•Heproposedafifthelement——aether(乙醚)—thedivinesubstancethatmakestheheavenlyspheresheavenlybodies(starsandplanets)ErroneousIdeas•1)InhisHistoryofAnimalsheclaimedthathumanmaleshavemoreteeththanfemales;•2)Galileo,showedbysimpleexperimentsthatAristotle'stheorythataheavierobjectfallsfasterthanalighterobjectisincorrect.•3)Heisoneofthemajorcontributorstothegeocentrictheory(地心说).APhilosophyfor2000Years•Aristotle’sschemeprovidedalogicallyconsistentexplanationforthemotionsoftheheavensandlifeonEarth.•Itcombinedmostofthepreconceptionsofhistimeintoagrandsystem.•Hisviewremainedthestandardconceptionfornearly2000years.