 our perceptions and come to know the essence and intimate nature of the objects of these perceptions". The "essence and intimate nature" of perceived object were the particles posited by theories as their micro-structure, e.g., "viewing the rapid movement of particles as constituting the essence of heat (1902b, 39). The only possible access to them is via hypotheses, but hypotheses are beyond the limits of experience. Hypotheses might well be indispensable in doing science but they are never a means to empirical knowledge. As he put it in an early piece: "let us never trust hypotheses for an instant, and in particular let us never attribute a body and a reality to the abstractions that the weakness of our nature imposes on us" (1892b, 177). How then can relations be knowable? For a start relations are captured by mathematical equations, which are constructed in such a way as to represent the formal properties of the empirical entities under investigation. For another, because of this formal character, resemblance is not required. It is worth repeating that for Duhem, theoretical physics starts with empirical objects and aims to "represent" their properties. But "in order to represent these properties, theoretical physics defines certain algebraic and geometric magnitudes and then establishes relations between these magnitudes which symbolize physical laws to which the system is subjected" (1892c, 39).These relations are among magnitudes which bear no resemblance to the actual physical properties; they are symbolic and abstract representations of these properties and as Duhem notes, stand in "no relation to [the] nature" of the properties they represent: "But we can put this non-quantitative property into correspondence with an algebraic magnitude which, without standing in any relation to its nature, will be a representation of it" (1892c, 47). Representation, then, cannot cut through relations. But of this representation something more can be said, if it meets the requirements noted above (viz., unity, simplicity and novel predictions): that it is (tends to be) natural. That the mathematical relations among the physical magnitudes express real relations among "hidden realities", of which "the essence"-what they are intrinsically so to speak-cannot be known. This kind of'relationist' approach to knowledge is not far from the one that Poincaré developed at roughly the same time in an attempt to defend the objectivity and value of science. In fact, Duhem himself spoke approvingly of Poincaré's attitude when he wrote: The logical analysis that he had made with
our perceptions and come to know the essence and suggest nature of the object of these perceptions ". The " essence and inner nature " of perceive object were the particles situate by theories as their micro - structure, for example, " watch the rapid movement of particle as constituting the essence of heating system (1902b, 39). The only possible access to them is via hypotheses, but hypotheses are beyond the limit of experience. Hypotheses might well be indispensable in doing skill but they are never a means to empirical cognition. As he put it in an early slice: " let us never hope hypotheses for an instant, and in particular get us never attribute a body and a reality to the abstractions that the weakness of our nature levy on us " (1892b, 177). How then can relations be knowable? For a start relations are captured by mathematical equations, which are constructed in such a way as to represent the formal property of the empirical entities under probe. For another, because of this conventional quality, resemblance is not required. It is worth duplicate that for Duhem, theoretical purgative starts with empirical objects and draw a bead on to " represent " their properties. But " in order to represent these properties, theoretical physics defines certain algebraic and geometric magnitudes and then establishes relations between these magnitude which symbolize forcible law to which the system is subjected " (1892c, 39).These relations are among magnitudes which hold no resemblance to the actual physical properties; they are symbolic and abstract representation of these property and as Duhem notes, stand in " no relative to [ the ] nature " of the properties they represent: " But we can frame this non - quantitative property into agreement with an algebraic magnitude which, without stand in any relation to its nature, will be a theatrical performance of it " (1892c, 47). Representation, then, cannot cut through relations. But of this representation something more can be said, if it meet the requirements noted above (viz. , unity, simplicity and novel predictions ): that it is (tends to be) natural. That the numerical relations among the physical magnitude express real relations among " hidden realities ", of which " the essence"-what they are intrinsically so to speak - cannot be sleep together. This kind of'relationist' approach to knowledge is not far from the one that Poincaré developed at roughly the same time in an attack to defend the objectivity and value of science. In fact, Duhem himself speak approvingly of Poincaré's attitude when he wrote: The logical analysis that he had made with
 oug perceptions and come tu know the esseuxe and intimzte natufe of the objects of these pxrceptionw". The "essence and intioate natuge" of perxeivtd object were thx particles poalted yy theories as tmeir micro-sdructure, e.g., "viawkny the rapid movement of particles as constiyuhing the essense og heaf (1902b, 39). The only possible access to tgem is nia hypotheses, buy hypotheses are beyond thf lilits of experience. Hypotheses migrr well be inaispensablt nn doing scjence but they are never a meanr to zmpirical kboqlefce. As he puv it ig an early plvce: "let us nevrr trust hypotmeses foe an instant, and in perticular let us nevgr attribude a body and a reaoiry to the absgeacgiohs tgat thf wxakness of kur nature umposes on us" (1892b, 177). Hoe eyen can relatjons bq hnowable? For a start relations are captlred by mathematical equatiins, which are construfted in stch a way as to represent the formal properties ox the dmpnvlcal wnhities under investigation. For another, becausq og nhis formal charagter, resemblance ix joy required. It ks worcg depeating that for Duhem, jheorerical phyfics starts with empirical objexts and aims ro "represent" their properties. But "in otder to represent these prolerties, thelretical lfysics defines cdrtsit algebraic and geometric iagnitudew anb then ertabkishes relations betwcan these magnituded whieh sykbolize phjsical laws to which the system is subjected" (1892v, 39).Dheve relatnons ave among magnittdes which beat no reseiblanze to the zctual 'hysical pro[erties; they dte symbolic aid abstrast rwprewentatiuvs of these prpperties cud as Duhwm notes, stand in "ko reuztion to [the] nacbrt" if the propertoes thqy rxpresqtt: "But we cat pug tfos nov-quantiuctiye oroprrty into correspondance with an algebraic mwgnitude which, wythout standimg in any relation to ivs natnre, wikl fe a representation of it" (1892c, 47). Rspresentahiok, then, cannot cut through relctions. But of this representation somethmng more can be said, if it meets the requitemtnts noted abpve (vyz., unity, vimplicity and novel predictions): that it is (tends to be) nafural. Dhat hhe mathematical relations among the physical magnitudes express real relqtions among "hiddeh reslitivs", jy which "the xssence"-what they sre intrinsically so to speak-cainot be knmwu. This kind of'relationist' apptoxch to knowleage is not far from the kne that Poincaré developed at roughly tne same time in an attemit to defwnd tge objvdtmvity and value of svience. In fqct, Duhwm hlmself spoke aoprpvlngly of Plinceré's attitude when he wrote: The logixal anqljsis that he had made with
our perceptions and come to know the intimate of the of these perceptions". of object were the posited by theories their micro-structure, e.g., "viewing the rapid of particles as constituting the essence of heat (1902b, 39). The only possible to them is via hypotheses, but hypotheses are beyond the limits of experience. might be in science but they are never a means to empirical knowledge. As he put it in an piece: "let us never trust hypotheses for an and in particular let never attribute a body and reality the abstractions the of nature imposes on (1892b, 177). How then can relations be knowable? For a start relations are captured by mathematical equations, are constructed a way to the properties of the under investigation. For another, because of resemblance is not required. It is worth repeating for Duhem, physics starts with empirical objects and to "represent" their properties. But "in order to these properties, theoretical physics defines certain algebraic and geometric magnitudes and then establishes relations between which symbolize physical laws which the system subjected" 39).These are magnitudes which no resemblance to the actual physical properties; they are symbolic and representations of these properties and as Duhem notes, stand in to nature" of the they represent: "But we put non-quantitative property into correspondence algebraic which, any to nature, will be a of it" (1892c, 47). Representation, cannot cut through relations. more can be said, if it meets the noted above (viz., unity, simplicity and novel that it is (tends to be) natural. That the mathematical relations among physical magnitudes relations among "hidden realities", of which "the essence"-what are intrinsically so to be known. This kind of'relationist' approach to knowledge is far the one Poincaré developed at the same time an attempt to objectivity and of In spoke approvingly of Poincaré's attitude when wrote: logical analysis that he had with
 our perceptions and come to knOw the essenCe and IntImaTe NatuRe of The objects of thESe peRceptions". The "essence and IntimAtE NatuRE" oF percEived obJEcT WEre ThE pArtIcLEs PositEd bY theoriEs as their mIcrO-sTructure, e.g., "viEWiNg the rapid MovEment of partiCleS as conStItuTIng thE esSence Of heat (1902B, 39). the onlY possible AcCEss to tHEm is via HYPoThesEs, but hypotheses arE BeYOnd the limits of ExperiEnCE. HYPOthEseS might well Be IndisPEnsable IN dOING scIEnce but they arE never a meanS To eMpiricAl KnoWLedge. AS he puT iT In aN early piece: "Let uS never truSt hypoTHeses foR An instaNt, and iN paRtiCulaR LeT uS neVeR AttRIbUte A BodY and a reaLiTy To the AbstRACTIons ThaT the WeaknEss of our naturE imPoseS On uS" (1892b, 177). How Then cAn reLaTions Be knowAble? FOr A start relations Are cAptured by MatHeMatIcAl equATions, wHicH arE constrUcted in SUch A wAY AS tO represent the formaL pROPeRties of tHe empiRIcAl ENtities uNdEr iNvesTIGatioN. For ANoTher, becaUse of tHIs FoRmal chaRaCter, reSeMblAncE is noT RequIred. It Is worth rEpeatINg that for Duhem, THeoretical phySIcS STaRTs wiTh eMpirical objEcts ANd aiMs to "REpResENt" theIr proPeRTiES. But "in order to represEnT these PropeRties, theoretiCal physics DEFInes certAin aLGeBRaic and geometrIc magNitudes and THen estabLisheS relatioNs between THEse magniTudEs wHicH syMBOlIze physical laWS To whIcH the sysTem Is subjeCteD" (1892c, 39).THesE reLaTions are aMong magnItUdEs WhIch Bear nO ResemblaNcE to ThE acTual pHYsical PropeRtieS; tHeY Are SymboliC AnD ABstrAcT rEpreSenTaTions Of thESe pRopertiEs and as DuHem NOtes, StAnD in "no reLation to [the] naTuRe" of the proPeRtiEs they REPresent: "BUt we can put this non-quantiTAtive prOpeRty inTo coRrespondeNce With an AlgEBraic mAgnituDe whiCh, WitHOUt staNDInG in AnY relation tO ITs nAture, WiLl be A represEntation of it" (1892c, 47). RepreSEntAtion, then, cannOt cUt thROUgH reLAtIOns. buT Of tHIS representation Something mOrE CaN be said, if iT MeeTs The requIrementS noteD Above (viZ., unity, simPlicity anD nOvel PREdiCtions): that It is (tendS to be) natuRAl. ThaT ThE mathEmaTical rElAtiOns amOng the PHysIcal mAgnituDeS expreSs reaL rElations Among "hidden realities", of wHich "thE esseNce"-What they aRe iNTriNsically sO to sPeak-cannot Be kNowN. This KinD Of'relAtioNIsT' apPRoach To knOWledge is nOT fAr fROM tHe one that PoINCAré DevelOpeD At rougHly tHe same time in an attEMpt to defend the ObjeCTIviTy aND valUe Of science. In facT, DuHeM HImself spOkE approvinglY of PoincArÉ'S attiTude whEn he wrOte: The lOGIcAL analySis tHat He had made WitH
 our perceptions and cometo know th e ess enc e a nd  int imat e nature of th e  obj ects of these percepti ons".  T h e "e s se nce a nd inti m at e nat ur e"  of  p e rc eived  ob ject we re the par tic le s posited by th eories asthe ir micro-str uct ure, e .g .," viewi ngthe r apid m o vement  of parti cl e s as c o nstitut i n gtheessence of heat ( 1 90 2 b, 39). The on ly pos si b le a cce ssto them is  v ia hy p otheses ,  b u t hyp o theses are be yond the li m its  of ex pe rie n ce. Hy pothe se s  mi ght well be  ind ispensabl e in d o ing sci e nce but  theyare  ne vera  m ea nsto emp i ri cal kno wledge.As  h e put  iti n a n ea rly  pie ce: " let us nevertru st h y pot heses  foran i ns tant,  and i n par ti cular let us ne verattribute  abo dyan d a r e alitytothe  abstra ctionst hat  t h e we akness of our natu re i mp oses onus" (1 8 92 b, 177). Ho wthe n ca n relat ions be  knowabl e? For ast art rel at ions a re  ca ptu red b y  mat hemati cal equa tions ,  which are con s tructed in su c ha wa y  astorepresent t he f o rmal  pro p er tie s  of t he em pi r ic a l entities under in ve stigat ion.For another,because of t h is forma l ch a ra c ter, resemblan ce is  not requi r ed. It i s wor th repea ting that f or Duhem , t heo ret ica l ph ysics startsw i th e mp iricalobj ects an d a ims  to  "r ep resent" t heir pro pe rt ie s.  Bu t "in order to  r epr es ent  thes e  prope rties , th eo re t ica l physi c sd e fine sce rtai n a lg ebrai c an d  ge ometric  magnitud esa nd t he nestabli shes relation sbetween th es e m agnitu d e s whichsymbolize physical laws to whic h t he sy stem  is subje cte d" (18 92c ,  39).T hese r elati on s a r e  amon g ma gni tu des whichb e arno re se mbla nce tothe actual physica l  pr operties; the y a re s y m bo lic an d  ab st r act r epresentationsof these p ro p er ties and a s  Du he m notes , stand  in " n o relat ion to [t he] natur e"  oft h e p ropertiesthey rep resent: " B ut we ca n put  th is non -q uan titat ive pr o per ty in to cor re sponde nce w it h an alg ebraic magnitude which,  witho ut st and ing in an y r e lat ion to it s na ture, will  be  arepre sen t ation  ofi t"  (1 8 92c,47). Represent a ti on, t he n, cannot c u t thr oughrel a tions.  But  of this represen t ation somethin g mo r e  ca n b e  sai d,  if it meets t here q u irements  n oted above(viz., u ni t y, si mplici ty and  novelp r ed i ctions ): t hat  it is (t end st o be) n at ur a l. Tha t th emathem atical rela t i ons among the ph ysica l magni t ude s exp re ss real rela tions amon g "hidden r ealiti es",  of w hich "t he  essen ce" -w hat they a r e intrins icall y so to  s peak -ca nnot b e kn o w n. Th is k in d o f'relatio n i st '  a pp r oac h to  know le dgeis not fa r  from th e o n e thatPo inc a r é deve l op e d  at roughl y t he sa m e  time in a n  att e mp t  to d efendthe ob jectivi t y a nd  valueofs c ience. In  fact, Du h emhi msel f spokeap prov in gly  o f Poincaré's at titude w hen he w r o te: Th e l o gica l  analy si s that he ha d mad ew ith
 our_perceptions and_come to know the_essence and_intimate_nature of_the_objects of these_perceptions". The "essence_and intimate nature" of_perceived object were_the_particles posited by theories as their micro-structure, e.g., "viewing the rapid movement of particles_as_constituting the_essence_of_heat (1902b, 39). The only_possible access to them is_via hypotheses,_but hypotheses are beyond the limits of experience._Hypotheses_might well be_indispensable in doing science but they are never a_means to empirical knowledge. As he_put it in_an_early_piece: "let us never_trust hypotheses for an instant, and_in particular let us never attribute_a body and a reality to the_abstractions that the weakness of our_nature imposes on us" (1892b,_177). How_then can relations be knowable?_For a start_relations are_captured by mathematical_equations, which are constructed in such_a way as_to represent the formal properties of_the_empirical entities under_investigation._For_another, because_of this formal_character,_resemblance is_not_required. It is worth repeating that_for_Duhem, theoretical physics starts with empirical objects_and aims to "represent"_their_properties. But "in order_to represent these properties, theoretical_physics defines certain algebraic and geometric_magnitudes and_then establishes_relations between these magnitudes which symbolize physical laws to which the_system is subjected" (1892c, 39).These relations_are among magnitudes which_bear no_resemblance_to the actual_physical_properties; they_are symbolic and abstract representations of these_properties and_as Duhem notes, stand in "no_relation to [the] nature"_of_the properties they represent: "But we_can put this non-quantitative property into_correspondence with an algebraic magnitude_which,_without_standing in any relation to_its nature, will be a representation_of it" (1892c,_47). Representation, then, cannot cut through relations._But_of this representation something more can_be_said, if it meets the requirements_noted_above_(viz., unity, simplicity and novel_predictions): that it is (tends to_be) natural. That the mathematical relations among the physical_magnitudes express real_relations among "hidden realities", of_which_"the_essence"-what they are intrinsically so to speak-cannot be known. This_kind of'relationist'_approach to knowledge_is not far from the one that Poincaré developed at_roughly the same time in an attempt_to defend the objectivity and value of science. In fact, Duhem_himself spoke approvingly of Poincaré's attitude when he_wrote: The logical analysis that he had_made with