 contradictions and unifying the empirical laws into a single system of hypotheses is for Duhem the road to perfection. In effect, Duhem argues that if science aims at a natural classification, then unification is the most natural thing to look for. A natural classification cannot possibly be "an incoherent collection of incompatible theories" (cf. 1893b, 67)-even though each and every theory may save some phenomena. Unification is then seen as a way to remove inconsistencies and to approach what Duhem calls the "perfect theory". Note that a natural classification is still a classification and not an explanation. What makes it natural is that the scheme for the classification, far from being arbitrary, is the one that nature itself uses, so to speak, to classify "the relations" that the causes of the empirical laws have among themselves. This, again, is an ideal form. Achieving it "infinitely surpasses the scope of human mind". But this does not mean that it does not exist; that is, there are true relations among the "essences" whose manifestation are the relations among the phenomena (the empirical laws). Given this ideal theory, it makes sense to aim to remove the contradictions among existing physical theories since the relations that there are among the causes of the phenomena are "neither indeterminate nor contradictory" (1893b, 68). This is the justification for the Unification Principle (UP): Physical theory has to try to represent the whole group of natural laws by a single system all of whose parts are logically compatible with one another (1906, 293). This principle was for him perfectly reasonable, though it could be denied without contradiction. So the key point we want to make is that the very idea of natural classification is part and parcel of a broader conception of reasonableness that Duhem endorsed in order to distinguish his view from the positivist ones in vogue in France in his time. As noted already, this reaction to positivism was thrown into sharp relief in his exchange with Rey. He actually compared Duhem to most of his contemporaries (notably, Rankine, Helmholtz, Dubois-Reymond, Ostwald, Poincaré and Milhaud). They take it to be the case that science explains nothing and that looking for causes is a venture into metaphysics. For them, Rey (1904, 703, M. G. translation) says, "Sciences merely record relations among phenomena, connections that are convenient to achieve an exact description of these relations, a description that allows
contradictions and unifying the empirical laws into a individual arrangement of hypotheses is for Duhem the road to perfection. In effect, Duhem argue that if science aims at a lifelike classification, then unification is the most lifelike matter to look for. A natural categorization cannot possibly be " an incoherent collection of incompatible hypothesis " (californium. 1893b, 67)-even though each and every theory may save some phenomena. Unification is then seen as a manner to remove inconsistencies and to approach what Duhem call the " perfect theory ". Note that a natural categorization is still a categorization and not an explanation. What makes it natural is that the scheme for the classification, far from being arbitrary, is the one that nature itself use, so to speak, to classify " the relations " that the causes of the empiric torah have among themselves. This, again, is an ideal form. Achieving it " infinitely surpasses the scope of human mind ". But this does not mean that it does not exist; that is, there are truthful relations among the " essences " whose demonstration are the relations among the phenomena (the empirical laws). give this ideal theory, it makes sense to aim to absent the contradictions among existing physical theories since the relations that there are among the campaign of the phenomena are " neither indeterminate nor contradictory " (1893b, 68). This is the justification for the Unification Principle (UP ): Physical theory has to try to act the whole group of natural laws by a single system all of whose character are logically compatible with one another (1906, 293). This principle was for him perfectly reasonable, though it could be deny without contradiction. So the key point we want to have is that the identical idea of natural classification is part and parcel of a wide conception of rationality that Duhem endorsed in order to identify his view from the positivist ones in vogue in France in his prison term. As noted already, this chemical reaction to positivism was thrown into sharp respite in his exchange with Rey. He actually compared Duhem to most of his contemporaries (notably, Rankine, Helmholtz, Dubois - Reymond, Ostwald, Poincaré and Milhaud). They take it to be the case that skill explains nothing and that looking for lawsuit is a venture into metaphysics. For them, Rey (1904, 703, M. G. translation) says, " Sciences merely record relations among phenomena, connections that are commodious to achieve an exact description of these relations, a description that allows
 cojtradictions and unifyinn the empirical laws invo a sihgle sysgem of hypotheses is for Duhxm tye roqd to perfection. In efwect, Duhel argues thau if science aims at a nabbral dpassnfmcation, then unlfication iv the most natgrxl thing to look for. A natural classisicatiom fannot possibli be "sg indoherent collection of incompatibls theorpes" (cf. 1893b, 67)-even thoigh each and every theory lay dave some phenomenw. Unificatiin if then seen ar a way to remove incohsistencies and to approach whag Duhzm calls thg "legxect theory". Note that a natuvsl clavsificayion is still s cnaswification and not an explanation. What iakes it tacural is that the schwmw for the clarwifkcauioi, fzr frol bxing arbitrzry, is the ine that nature itstlf lxes, so to spsak, to cjassify "the relations" that the causes ox tge empirical laws have qmong themselves. This, again, is an ideal form. Achieving it "infinitely surpasses dhe srooe if fymwn mind". But this does not mean that it does njf txixt; that is, theve are true relatipnd siong the "essevces" wkkss manifestation arf the rglatiobs among uhe pnenomena (the empirical laws). Given this pdeao theory, it makes dense to aio to remofe the contradictions aoong existing pjysical tgdories since the rekadions that there are among the causxs of the phdnomgna are "neither ijdetevkinate nor contradlctori" (1893b, 68). Tvis is the justification for the Unificatmpn Principle (U[): Pvysical cheory has to try tj represent thg whole gxoup ow natural maws by a single srstem all of fjose parts ace logicajly xompqtible dkth one anothet (1906, 293). This irnnciple wqs for him perfectky tezsonable, though it could be deniec wkthjun cpnesadiction. So the keh poing we want ti makr is that the very igea kf natural classifocwtion is part anq parcel of a broader conceptioj of ceasoneblenexs jhat Duhem endorsed in order to distingulsh his view frjm tme pjsitivist pnes in vogue in France in his time. As ioted already, this reacrion to positivism cax thrown invo shawp relief in his exchange wity Rey. He actually compared Duhem to moat of vis clntemporaries (notably, Rankine, Helmholtz, Dubois-Reymond, Ostwald, Poincaré and Milhand). They take jt tp be nhe ease thwt srixnce explains notning and that looking for causer is a vancure into metaphysics. For thek, Fey (1904, 703, M. G. travslation) says, "Sciences msrely revord relations among phenomena, vonnections that are conyenient ti achjeve an exect description of tnese rzlatiobs, a dewcriition that alluws
contradictions and unifying the empirical laws into system hypotheses is Duhem the road argues if science aims a natural classification, unification is the most natural thing look for. A natural classification cannot possibly be "an incoherent collection of incompatible (cf. 1893b, 67)-even though each and every theory may save some phenomena. Unification then as way remove inconsistencies and to approach what Duhem calls the "perfect theory". Note that a natural classification still a classification and not an explanation. What it natural is that scheme for the classification, far being is the that itself so to speak, classify "the relations" that the causes of the empirical laws have among themselves. This, again, is an form. Achieving surpasses the of mind". this does not it does not exist; that is, relations among the "essences" whose manifestation are the among the (the empirical laws). Given this ideal it makes sense to aim to remove the among existing physical theories since the relations that there are among the causes of the "neither indeterminate nor contradictory" 68). This is justification the Principle Physical theory to try to represent the whole group of natural laws by single system all of whose parts are logically compatible with (1906, This principle was him perfectly reasonable, though could denied without contradiction. So point want that very of natural classification is and parcel of a broader of reasonableness that Duhem his view from the positivist ones in vogue France in his time. As noted already, reaction to positivism was thrown into sharp relief in his exchange with He actually to most of his contemporaries (notably, Rankine, Helmholtz, Ostwald, Poincaré and Milhaud). take it to be the case that science explains and looking for is a venture metaphysics. For them, (1904, 703, M. says, "Sciences record among are convenient to achieve an exact of relations, a description that allows
 contradictions and unifying The empiricAl lawS inTo a SiNgle SystEm of hypotheses IS for duhem the road to perfectiOn. In eFfECt, DuHEm ArgueS that if SCiENCe aImS aT a nAtURaL clasSifIcation, Then unificAtiOn Is the most natURaL thing to loOk fOr. A natural clAssIficatIoN caNNot poSsiBly be "An incoHErent cOllection Of INcompaTIble theORIeS" (cf. 1893b, 67)-Even though each and EVeRY theory may save Some phEnOMeNA. uniFicAtion is theN sEen as A Way to reMOvE INConSIstencies and tO approach whAT DuHem calLs The "PErfect TheorY". NOTe tHat a natural ClasSificatioN is stiLL a classIFicatioN and noT an ExpLanaTIoN. WHat MaKEs iT NaTurAL is That the sChEmE for tHe clASSIFicaTioN, far From bEing arbitrary, Is tHe onE ThaT natuRe itsElf uSeS, so to Speak, tO clasSiFy "the relations" tHat tHe causes oF thE eMpiRiCal laWS have aMonG thEmselveS. This, agAIn, iS aN IDEaL form. Achieving it "inFiNITeLy surpasSes the SCoPe OF human miNd". but This DOEs not Mean THaT it does nOt exisT; ThAt Is, there ArE true rElAtiOns Among THe "esSences" Whose manIfestATion are the relaTIons among the pHEnOMEnA (The eMpiRical laws). GiVen tHIs idEal tHEoRy, iT Makes Sense To AIm TO remove the contradicTiOns amoNg exiSting physical Theories siNCE The relatIons THaT There are among tHe cauSes of the phENomena arE "neitHer indetErminate nOR ContradiCtoRy" (1893b, 68). thiS is THE jUstification fOR The UNiFicatioN PrInciple (uP): PHysIcaL thEoRy has to trY to repreSeNt ThE wHolE grouP Of naturaL lAws By A siNgle sYStem alL of whOse pArTs ARe lOgicallY CoMPAtibLe WiTh onE anOtHer (1906, 293). ThIs prINciPle was fOr him perfEctLY reaSoNaBle, thouGh it could be deNiEd without cOnTraDictioN. sO the key pOint we want to make is that tHE very idEa oF natuRal cLassificaTioN is parT anD Parcel Of a broAder cOnCepTIOn of rEASoNabLeNess that DuHEM enDorseD iN ordEr to disTinguish his view froM The Positivist oneS in VoguE IN FRanCE iN His TiME. As NOTed already, this rEaction to pOsITiVism was thrOWn iNtO sharp rElief in His exCHange wiTh Rey. He acTually comPaRed DUHEm tO most of his ContempoRaries (notABly, RaNKiNe, HelMhoLtz, DubOiS-ReYmond, ostwalD, poiNcaré And MilHaUd). They Take iT tO be the caSe that science explains noThing aNd thaT loOking for cAusES is A venture iNto mEtaphysics. for TheM, Rey (1904, 703, M. g. trANslatIon) sAYs, "sciENces mErelY Record relATiOns AMOnG phenomena, cONNEctIons tHat ARe convEnieNt to achieve an exacT Description of tHese RELatIonS, A desCrIption that alloWs
 contradictions and unifyi ng the emp irica l l aws  i ntoa si ngle system of hypo theses is for Duhem th e roa dt o pe r fe ction . In ef f ec t ,  Du he marg ue s  t hat i f s cienceaims at anat ur al classific a ti on, then u nif ication is t hemost n at ura l  thin g t o loo k for. A natu ral class if i cation cannotp o ss ibly  be "an incoheren t  c o llection of in compat ib l et h eor ies " (cf. 189 3b , 67) - even th o ug h e ach and every the ory may sav e  so me phe no men a . Unif icati on isthen seen a s away to re move i n consist e ncies a nd toapp roa ch w h at  D uhe mc all s  t he" per fect the or y" . Not e th a t a  nat ura l cl assif ication is st ill  a c l ass ifica tionandno t anexplan ation .What makes it n atur al is tha t t he  sc he me fo r  the c las sif ication , far f r ombe i n g  a rbitrary, is the o ne t ha t nature  itsel f  u se s , so tosp eak , to c lassi fy " t he  relatio ns" th a tth e cause sof the  e mpi ric al la w s ha ve amo ng thems elves .  This, again,i s an ideal fo r m. A ch i evin g i t "infinite ly s u rpas sest he  sc o pe of  huma nm in d ". But this does no tmean t hat i t does not ex ist; thati s ,  there a re t r ue relations amon g the  "essences "  whose m anife stationare the r e l ations a mon g t hephe n o me na (the empir i c al l aw s). Giv enthis id eal  th eor y,it  makes se nse to a im  t ore mov e the contradi ct ion samo ng ex i stingphysi calth eo r ies  sincet he r elat io ns  tha t t he re ar e am o ngthe cau ses of th e p h enom en aare "ne ither indeter mi nate nor c on tra dictor y "  (1893b,  68). This is the justi f ication  fo r the  Uni ficationPri nciple  (U P ): Phy sicaltheor yhas t o try t orep re sent the w h o legroup  o f na tural l aws by a single sy s tem  all of whose  pa rtsa r elog i ca l lyco m pat i b le with one ano ther (1906 ,2 93 ). This pr i nci pl e was f or himperfe c tly rea sonable,though it  c ould b e d enied with out cont radiction .  So t h ekey p oin t we w an t t o mak e is t h atthe v ery id ea  of na tural  c lassific ation is part and parce l of a  broa der  concepti ono f r easonable ness  that Duhe m e ndo rsedino rderto d i st ing u ish h is v i ew from t h epos i t iv ist ones in v o gue  in F ran c e in h is t ime. As noted alr e ady, this reac tion t o p osi t ivis mwas thrown int o s ha r p  reliefin  his exchan ge withRe y . Heactual ly com pared D u h em to mos t of  hi s contemp ora ri e s (nota bl y, Rankin e, H el mholtz , Dubo i s-Re y m ond, Ostwald, Po incar é and M i lha ud).Th ey take it t o be the c ase that sc ienceexpl ainsnothing  a nd tha t l oo king for c a uses is a  vent ure int ometa phy sics.Fort h em, R ey ( 19 04,  703, M.G .  t r an sl a tio n) s ays,"S cien ces merel y  recordrel a tions a mo ngp h enomen a ,c o nnectionstha t are c onvenientt o ac h ie v e anexactdescri ption o f  th es e relat ion s ,  a descri ption tha t  al lo ws
 contradictions_and unifying_the empirical laws into_a single_system_of hypotheses_is_for Duhem the_road to perfection._In effect, Duhem argues_that if science_aims_at a natural classification, then unification is the most natural thing to look for._A_natural classification_cannot_possibly_be "an incoherent collection of_incompatible theories" (cf. 1893b, 67)-even_though each_and every theory may save some phenomena. Unification_is_then seen as_a way to remove inconsistencies and to approach what_Duhem calls the "perfect theory". Note_that a natural_classification_is_still a classification and_not an explanation. What makes it_natural is that the scheme for_the classification, far from being arbitrary, is_the one that nature itself uses,_so to speak, to classify_"the relations"_that the causes of the_empirical laws have_among themselves._This, again, is_an ideal form. Achieving it "infinitely_surpasses the scope_of human mind". But this does_not_mean that it_does_not_exist; that_is, there are_true_relations among_the_"essences" whose manifestation are the relations_among_the phenomena (the empirical laws). Given this_ideal theory, it makes_sense_to aim to remove_the contradictions among existing physical_theories since the relations that there_are among_the causes_of the phenomena are "neither indeterminate nor contradictory" (1893b, 68). This_is the justification for the Unification_Principle (UP): Physical theory_has to_try_to represent the_whole_group of_natural laws by a single system all_of whose_parts are logically compatible with one_another (1906, 293). This_principle_was for him perfectly reasonable, though_it could be denied without contradiction._So the key point we_want_to_make is that the very_idea of natural classification is part_and parcel of_a broader conception of reasonableness that Duhem_endorsed_in order to distinguish his view_from_the positivist ones in vogue in_France_in_his time. As noted already,_this reaction to positivism was thrown_into sharp relief in his exchange with Rey. He_actually compared Duhem_to most of his contemporaries_(notably,_Rankine,_Helmholtz, Dubois-Reymond, Ostwald, Poincaré and Milhaud). They take it to_be the_case that science_explains nothing and that looking for causes is a venture_into metaphysics. For them, Rey (1904, 703,_M. G. translation) says, "Sciences merely record relations among phenomena, connections_that are convenient to achieve an exact description_of these relations, a description that allows