 of probabilities. It merely expresses the fact that a concept of probability will be useless if it is impossible in principle to find out what the probabilities are" (Salmon [1966], p. 64). Indeed, the only reason Hawthorne provides for the existence of the degrees-of-support function is that it solves the problem of old evidence. We think that this account bears too much resemblance to the deus ex machina strategy. A similar account is presented in Williamson ([2000], ch. 10), who stipulates that there exists an "evidential probability" measure that plays the role of the confirmation function. Having in mind the betting interpretation of an agent's degrees of belief Williamson explicitly rejects the demand for 10 an operational definition of evidential probability and merely says that it satisfies the axioms of the probability calculus. The only reason he provides for the existence of the evidential probability measure is his dissatisfaction with the notion of an agent's rational degrees of belief. We agree that there is no need for an operational definition of evidential probability. However, we think that the agent's betting behavior is merely used to measure, not to define, the agent's degrees of belief. In accordance with the above criterion of ascertainability we think that a theory of measurement is something highly desirable. Without such a theory more has to be said about why we are entitled to assume that there exists an evidential probability measure. As with Hawthorne's account of degrees-of-support, but in stark contrast to Williamson's account of knowledge, we think that Williamson's account of evidential probability bears too much resemblance to the deus ex machina strategy. Hawthorne ([2005]) and Williamson ([2000], ch. 10) stipulate the existence of a degrees-of-support function and an evidential probability measure, respectively. Taken as the confirmation function each would be sufficiently independent of, but appropriately linked to, the agent's degree of belief function in order for confirmation to be a means to the end of saying how worthy of belief certain hypotheses are. However, we do not think these authors provide sufficient reason for us to be entitled to assume the existence of these functions. Their accounts bear too much resemblance to the deus ex machina strategy. We both think that the only notion whose existence and intelligibility may be safely assumed and which is sufficiently independent of, but appropriately linked to, the agent's degree of belief function, is the agent's initial or a priori degree of belief function. We both also think that this conclusively establishes that there
of probabilities. It merely expresses the fact that a concept of probability will be useless if it is impossible in principle to find out what the probability are " (Salmon [ 1966 ], p. 64). Indeed, the lone reason Hawthorne provides for the existence of the degree - of - support function is that it solve the problem of old evidence. We remember that this account bears besides much resemblance to the deus ex machina strategy. A similar bill is give in Williamson ([ 2000 ], ch. 10), who stipulates that there exists an " evidential probability " measure that plays the role of the ratification function. Having in mind the bet interpretation of an agent's degree of belief Williamson explicitly reject the demand for 10 an operational definition of evidential probability and merely says that it satisfies the axioms of the probability tartar. The only reason he provides for the existence of the evidential probability measure is his dissatisfaction with the notion of an agentive role's intellectual degree of belief. We agree that there is no need for an operational definition of evidential probability. However, we think that the agentive role's betting demeanor is merely used to measure, not to specify, the agentive role's academic degree of belief. In accordance with the above criterion of ascertainability we think that a theory of measurement is something highly desirable. Without such a theory more has to be say about why we are entitled to assume that there exists an evidential probability measure. As with Hawthorne's account of degrees - of - accompaniment, but in stark contrast to Williamson's account of knowledge, we remember that Williamson's account of evidential probability have a bun in the oven too much resemblance to the deus ex machina strategy. Hawthorne ([ 2005 ]) and Williamson ([ 2000 ], ch. 10) stipulate the existence of a degrees - of - support affair and an evidential probability measure, respectively. Taken as the confirmation affair each would be sufficiently independent of, but appropriately linked to, the agent's degree of impression function in order for confirmation to be a means to the end of say how worthy of impression certain hypotheses are. However, we do not think these authors leave sufficient reason for us to be entitled to wear the universe of these functions. Their accounts bear too much resemblance to the deus ex machina strategy. We both think that the only notion whose existence and intelligibility may be safely assume and which is sufficiently independent of, but appropriately linked to, the agentive role's degree of belief function, is the agent's initial or a priori degree of belief function. We both besides think that this conclusively establishes that there
 of probabilities. It merely expresses the yqct thet a cohcept of probability will be useless id it us impossible in princkple to fpnd out wyat uhe probabilities are" (Salmon [1966], p. 64). Indzev, the only reaspn Hawthorte provides fos ghz existence of the degrees-of-support sunctiom ls that it soldes uhe proglem of old evidence. We think that this abcount bears too kuch resemblance to the deks ed machina strategy. A similar qccotbt is presenged in Williamson ([2000], ch. 10), who stipulates that there exisgs an "evidentiao prohdbility" meawure nhat plays thc role mf the vonfirmation fmnctimn. Yaving in mind the bevting interpretation of an aganc's degrees of belief Qioliamvon axplkxituy deoecfs the dejand for 10 zn operatiobal definition of efiqvmtial probabjlity wnq merely says that it satisfies the aximms of the probability calxulus. The only reason he proviqes for the existence of the evidential probabilidy meesjre if yid dissatisfaction with the notion of an agent'f rstponal degrees of nelief. We agree thst tngre is no need for au olerational definitlon of gvidenrial probwbiloty. However, we think that tye agent's bentint behavior is merepy used to oeasore, noy to define, the agent's begreea of belief. In accorsxnce with the abuve csiterion of ascertainabiliey we thiik thct a theury pf meafurement id somcdhing highly desirwble. Cithogt such a hheory more has to be said abouv why we are gnthtlvd to assbme thst there exises an evidenticl probayility measure. Aa with Iawthorne's ascount of degsges-of-support, uut in stwrk xonteast to Dilliamson's acvount of knowledge, qe think that Willlamsov'a account of evnbebtial probabiliyy ceaws tpo kuch resembldnce to yhe ddus ex machlna strstegy. Hawthorne ([2005]) and Wilmiamson ([2000], ch. 10) stipukabe the exustence jf a degrees-og-support function wnd ai evidxntial prjbability measure, respectively. Taken as thc confirmatiog fukctijn each wobld be sufficiently independent of, but a'propriately linked to, rhe agent's degree oy nelief functmon in order fos confirmation to be a means to the ekd of saying how worthg of balief certain hypotheses are. However, we do not think these authors provide sufdicienv weason for hs tp be vntntlzd to afsumx vhe existence of nhese functions. Their accounts bxar too muwh resemblance to the deus ex kazhina strategi. We both think that the ohly notipn whose existence and intelligobility may be safely asxumed ane whidh is suffmciently independent of, buc appripriateoy llnked to, the aeeny's degree ov bekizf function, is the agent's initial or a prlori degree of bxlief functilk. We bkth alfo think that thjs ckjcluskvely establixhes that therr
of probabilities. It merely expresses the fact concept probability will useless if it find what the probabilities (Salmon [1966], p. Indeed, the only reason Hawthorne provides the existence of the degrees-of-support function is that it solves the problem of evidence. We think that this account bears too much resemblance to the deus machina A account presented in Williamson ([2000], ch. 10), who stipulates that there exists an "evidential probability" measure that the role of the confirmation function. Having in the betting interpretation of agent's degrees of belief Williamson rejects demand for an definition evidential probability and says that it satisfies the axioms of the probability calculus. The only reason he provides for the of the measure is dissatisfaction the of an agent's of belief. We agree that there for an operational definition of evidential probability. However, think that agent's betting behavior is merely used measure, not to define, the agent's degrees of In accordance with the above criterion of ascertainability we think that a theory of measurement highly desirable. Without such theory more has be about we entitled to that there exists an evidential probability measure. As with Hawthorne's account degrees-of-support, but in stark contrast to Williamson's account of knowledge, that account of evidential bears too much resemblance the ex machina strategy. Hawthorne Williamson ch. existence a function and an evidential measure, respectively. Taken as the function each would be linked to, the agent's degree of belief function order for confirmation to be a means the end of saying how worthy of belief certain hypotheses are. However, do not authors provide sufficient reason for us to be to assume the existence these functions. Their accounts bear too much resemblance to deus machina strategy. both think that only notion whose and intelligibility may assumed and is independent linked to, the agent's degree of function, the agent's initial or a degree function. We both also think that this conclusively establishes that there
 of probabilities. It merely exPresses the Fact tHat A coNcEpt oF proBability will be USeleSs if it is impossible in prIncipLe TO finD OuT what The probABiLITieS aRe" (salMoN [1966], P. 64). INdeed, The Only reaSon HawthorNe pRoVides for the eXIsTence of the DegRees-of-supporT fuNction Is ThaT It solVes The prOblem oF Old eviDence. We thInK That thIS accounT BEaRs toO much resemblance tO ThE Deus ex machina sTrategY. A SImILAr aCcoUnt is preseNtEd in WILliamsoN ([2000], Ch. 10), WHO StiPUlates that theRe exists an "eVIdeNtial pRoBabILity" meAsure ThAT plAys the role oF the ConfirmatIon funCTion. HavINg in minD the beTtiNg iNterPReTaTioN oF An aGEnT's dEGreEs of beliEf wiLliamSon eXPLICitlY reJectS the dEmand for 10 an opeRatIonaL DefInitiOn of eVideNtIal prObabilIty anD mErely says that it SatiSfies the aXioMs Of tHe ProbaBIlity cAlcUluS. The onlY reason HE prOvIDES fOr the existence of thE eVIDeNtial proBabiliTY mEaSUre is his DiSsaTisfACTion wIth tHE nOtion of aN agent'S RaTiOnal degReEs of beLiEf. WE agRee thAT theRe is no Need for aN operATional definitiON of evidential PRoBABiLIty. HOweVer, we think tHat tHE ageNt's bETtIng BEhaviOr is mErELy USed to measure, not to deFiNe, the aGent's Degrees of beliEf. In accordANCE with the AbovE CrITerion of ascertAinabIlity we thiNK that a thEory oF measureMent is somETHing highLy dEsiRabLe. WITHoUt such a theory MORe haS tO be said AboUt why we Are EntItlEd tO aSsume that There exiStS aN eViDenTial pRObabilitY mEasUrE. As With HAWthornE's accOunt Of DeGReeS-of-suppORt, BUT in sTaRk ContRasT tO WillIamsON's aCcount oF knowledgE, we THink ThAt williamSon's account of EvIdential prObAbiLity beARS too much Resemblance to the deus ex mAChina stRatEgy. HaWthoRne ([2005]) and WilLiaMson ([2000], ch. 10) StiPUlate tHe exisTence Of A deGREes-of-SUPpOrt FuNction and aN EVidEntiaL pRobaBility mEasure, respectively. tAkeN as the confirmAtiOn fuNCTiOn eACh WOulD bE SufFICiently independEnt of, but apPrOPrIately linkED to, ThE agent's Degree oF beliEF functiOn in order For confirMaTion TO Be a Means to the End of sayIng how worTHy of bELiEf cerTaiN hypotHeSes Are. HoWever, wE Do nOt thiNk thesE aUthors ProviDe SufficieNt reason for us to be entitlEd to asSume tHe eXistence oF thESe fUnctions. THeir Accounts beAr tOo mUch reSemBLance To thE DeUs eX MachiNa stRAtegy. We boTH tHinK THaT the only notION WhoSe exiSteNCe and iNtelLigibility may be saFEly assumed and wHich IS SufFicIEntlY iNdependent of, buT apPrOPRiately lInKed to, the ageNt's degreE oF BelieF functIon, is tHe agent'S INiTIal or a PrioRi dEgree of beLieF fUNction. WE bOtH Also thInk tHaT this cOnclusIVely ESTablishes that theRe
 of probabilities. It mere ly express es th e f act  t hata co ncept of proba b ilit y will be useless if i t isim p ossi b le  in p rincipl e  t o fin dou t w ha t  t he pr oba bilitie s are" (Sa lmo n[1966], p. 6 4 ).  Indeed, t heonly reasonHaw thorne  p rov i des f orthe e xisten c e of t he degree s- o f-supp o rt func t i on  isthat it solves th e  p r oblem of old e videnc e. We t hin k t hat this a cc ountb ears to o  m u c h  re s emblance to t he deus exm ach ina st ra teg y . A si milar  a c cou nt is prese nted  in Willi amson( [2000], ch. 10) , whosti pul ates th at  th er e  ex i st s a n  "e videntia lpr obabi lity " m e asur e t hatplays  the role ofthe  con f irm ation  func tion .Havin g in m ind t he  betting interp reta tion of a n a ge nt' sdegre e s of b eli efWilliam son exp l ici tl y r ej ects the demand fo r1 0  a n operat ionald ef in i tion ofev ide ntia l proba bili t yand mere ly say s  t ha t it sa ti sfiesth e a xio ms of theprobab ility ca lculu s . The only rea s on he provide s  f o r  t h e ex ist ence of the  evi d enti al p r ob abi l ity m easur ei sh is dissatisfactionwi th the  noti on of an agen t's ration a l degreesof b e li e f. We agree th at th ere is non eed foran op erationa l definit i o n of evi den tia l p rob a b il ity. However, w e th in k thatthe  agent' s b ett ing  be ha vior is m erely us ed  t ome asu re, n o t to def in e,th e a gent' s  degre es of  bel ie f. Inaccorda n ce w ithth eabov e c ri terio n of asc ertaina bility we  th i nk t ha ta theor y of measurem en t is somet hi nghighly d esirable . Without such a theory more ha s t o besaid  about wh y w e areent i tled t o assu me th at  th e r e exi s t sanev idential p r o bab ility  m easu re. Aswith Hawthorne's a c cou nt of degrees -of -sup p o rt , b u ti n s ta r k c o n trast to Willia mson's acc ou n tof knowled g e,we  thinkthat Wi lliam s on's ac count ofevidentia lprob a b ili ty bears t oo muchresemblan c e tot he  deus  ex  machi na  st rateg y. Haw t hor ne ([ 2005])  a nd Wil liams on  ([2000] , ch. 10) stipulate the  exist enceofa degrees -of - sup port func tion  and an ev ide nti al pr oba b ility  mea s ur e,r espec tive l y. Takena sthe c on firmation f u n c tio n eac h w o uld be  suf ficiently indepen d ent of, but ap prop r i ate lyl inke dto, the agent' s d eg r e e of bel ie f functionin order  f o r con firmat ion to  be a m e a ns to the  end  of  saying h owwo r thy ofbe li e f cert ainhy pothes es are .  How e v er, we do not th ink t h e se au t hor s pro vi de suff i cien t reason f or us to be  entit ledto as sume th eexiste nce  o f these fu n ctions. T heiraccount sbear  to o much  res e m blanc e to  t hedeus ex m a c hi n ast r ate gy.We bo th  thi nk that t h e only n oti o n whose  e xis t e nce an d  i n t elligibili tymay b e safely ass u meda nd which  is su fficie ntly in d epe nd ent of,  bu t appropria tely link e d t o,  the  agent's  d egre eofbe lief function,is the a gent's i n i tial o r a prio r i degr ee  of belief f uncti on .  We bot h als o think tha t t his  con clu sive l y establishes that there 
 of_probabilities. It_merely expresses the fact_that a_concept_of probability_will_be useless if_it is impossible_in principle to find_out what the_probabilities_are" (Salmon [1966], p. 64). Indeed, the only reason Hawthorne provides for the existence_of_the degrees-of-support_function_is_that it solves the problem_of old evidence. We think_that this_account bears too much resemblance to the deus_ex_machina strategy. A_similar account is presented in Williamson ([2000], ch. 10),_who stipulates that there exists an_"evidential probability" measure_that_plays_the role of the_confirmation function. Having in mind the_betting interpretation of an agent's degrees_of belief Williamson explicitly rejects the demand_for 10 an operational definition of_evidential probability and merely says_that it_satisfies the axioms of the_probability calculus. The_only reason_he provides for_the existence of the evidential probability_measure is his_dissatisfaction with the notion of an_agent's_rational degrees of_belief._We_agree that_there is no_need_for an_operational_definition of evidential probability. However, we_think_that the agent's betting behavior is merely_used to measure, not_to_define, the agent's degrees_of belief. In accordance with_the above criterion of ascertainability we_think that_a theory_of measurement is something highly desirable. Without such a theory more_has to be said about why_we are entitled to_assume that_there_exists an evidential_probability_measure. As_with Hawthorne's account of degrees-of-support, but in_stark contrast_to Williamson's account of knowledge, we_think that Williamson's account_of_evidential probability bears too much resemblance_to the deus ex machina strategy._Hawthorne ([2005]) and Williamson ([2000],_ch._10)_stipulate the existence of a_degrees-of-support function and an evidential probability_measure, respectively. Taken_as the confirmation function each would be_sufficiently_independent of, but appropriately linked to,_the_agent's degree of belief function in_order_for_confirmation to be a means_to the end of saying how_worthy of belief certain hypotheses are. However, we do_not think these_authors provide sufficient reason for_us_to_be entitled to assume the existence of these functions. Their_accounts bear_too much resemblance_to the deus ex machina strategy. We both think that_the only notion whose existence and intelligibility_may be safely assumed and which is sufficiently independent of, but_appropriately linked to, the agent's degree of belief_function, is the agent's initial or a_priori degree of belief_function._We both also think that this conclusively_establishes_that_there