The Validity of Aquinas'Third Wry BY REM B. ED\TARDS [Reprinted f.rom The l{eu Scholosticism, XLV, l, Winter, 1971.] I i I, DISCUSSION ARTICLE III: The Validity of Aquinas'Third Way by Rem B. Edvards In a recent ltind article,l I attempted to show that the basic argument in Aquinas' "third lraI " was not logically failacious, however questionable the truth of some of its premises uright be. Even more recentlv, Thomas Mautner 2 has attempted to show that I faiied to demonstrate the validity of the basic pattern of reasoning which I believe to be involved in this proof. I think that he has not succeeded, though he may have shown that in proclucing what I believe to be a logically valid version of the cosmological argument, I was more original than I had at first thought myself to be. Since his treatment of my positiou is very brief, I shaIl quote what he has to say and then try to give an appropriate response. (A) Suppose that we have an argument of the form P therefore C, and that this argument is invalid.-It could always be said that P, therefore C, is valid-although-enthymematic: the suppressed premiss being Q, where Q entails P I C. This would. be to say that there are no logical fallacies. (At worst, an argument would be enthymematic!)B This is an interesting problem, not just for mv treatment of the " third" wayr" but for logicians and" writers of introductory logic textbooks in general. Philo."ophers do have a problem of agreeing upon criteria to be used for " sameuess of argument." \1'e can makc these criteria very strict and insist upon evaluating each argument simply on the basis of what is explicitly given, just as it is given. \Yith such strict criteria we shall not find verv many good arguments outside of the conlines of textbooks on logic where we are told in advance to treat certain arguments as enthymemes and l Rem B. Ed.rvard.s, " Composition and the Cosmological Argument," Mi,nd, LXXVII, 115-17. 2 Thomas Mautner, " Aquinas's Third W'ay," Americom Philosophiaal Quorterly, 6, 298-304. 8 lbid,.,30t-302. 117 118 Rent, B. Ed,ward,s otirers as invalid or vaiicl, and ttre suspicion of manv unclelgraduates will ber c,onfirmed that logic is useless once l{e get outsicle thc confines of the contrived exercises at the end of the chalrter'. Mautner seems to be opting fol the Scylla oll such srrict criteria for " samertess of argument," fearing the Charv]-rdis of the r-rpposite extrerneitavinq to regarcl every " invalic1" argnmerrt as an enthyrneme. I1.: i*s quite coruect in maintaining that urittr the addition of just thc right premises, an.y invalid argurnent rna-v be converted into ir ralicl argument; so there is this rlanger to be ctrrearlecj as wcll. Elow shatrl we ever fincl examples oll invalid argriments to give as exercises in our logic textbooks if we gc this far ? ldorrever, ther:c i-q also the peril of having to rluit writins ancl talking about enthyrnemes altogr:thei', and this we mav also want to resist. Most professional 1rhilo.;ophers do not believe tirat recognizing some argurnents, n hiclr ar.'e othelwise invalicl, as enthvmernes rrnd supplying arllitional lrremises to boi.qter them ul) commits thern to the extreme view tliat, ail invalid argurnents are valitl enthymunes. Thi*q mav hrr on1.y because they do not -qee the end of the road however. ancl l:[arttner may be quite correci, in insisting that thi-q is w]rat it finall;.' conx:s to. Certainlv there are iuescapable element-q of subjectivitl, in ascertaining what an olisiual ar:guer might irave liad " in thrr back of his rnind " or: that he " u'oulrl have accepte cl if askecl " i'r " r,r,ould have accepterj it he hacl lefiecterl enoush " or the 1ike. M_v o\\'11 inclination woukl be to appl.y very genel.olls cr:iteria for 'l sanrn,rnss of algumcr)t." l{ tiris fina1lv implios that all invaiicl alguments are enthl,msmes, I think that rre should jrist harre to live with it. There are methodological considerations uncler'lying such generosity, holrever. Aside t'rom wanting logic to ire applicable beyonr[ the artificial exelcists sir.cn in logic textbooks, I also do rrot think that a philcsopher can talie any great p::ide in refuting his opponent at his weal<est. Eut i{ it is possibie to clo him in after givina hjm the benefit of the dolbt, then this is a significant lrhilosophicai achiei,ement. If at its strongest a philosophical position will not bear up nncler e,xamination, then we have the best of rr.asons for rejecting it. (ts) C'lor:rectlvr Edwards draws attention to the faet that although in g'eneral argurnents of the form: tr all parts of W are F; therefore \\r is l'," are invalid, some arg;uments r:f this form rnav still be valid, not in yirtue of having that forrn, but in virtue of some other feature.a 4 lbid., 302. The Valid,ity of Aquhws' Th,ird, Wo'y 119 Aithough l agree that al,l arguments of the suggested form are invalid,, I explicitly denu tha,t " sailLe arguments of this form may still be valicl." If I helcl such a position 1 rvould, be contradicting myself, and this I have not clone. Arguments from part tolvhole may he valicl b1, 1,11i1r. of having so111e other folm, but pot br riltue of having just tltat form. I also do not hold that such argrrments are "in general" invaUd. Tn the .qomeryhat technical and precise sense in rvlrich logicians 1ls€r the terms " valid " and " invalic'lr" tliele is no such thing as " in general " r.alidit"v or invalidity. If an arsument folm is srich that it is possible in only one instancc for all its premises to l:e true and its conclusions false, that form is sint,ltll1 invalicl, not just rareLq valicl but tm genernl invalici. trIaving ac.lmittetl that ail argriments o{ the form " aii parts of \V a::e 1'; therefore W i-* I"'are invalid, I rnust now point out that this is not the form of the argument which tr used in my re-wording oI Aquinas" " thircl w&-y." The form which I used rvas perfectly r.alid, having no possible substitution instances rvith ali true premises and a false conclusion. 'I'he form which I used was: " If rrll parts of W are L', tiLen \Y i.. .tr'; and, all parts of \Y are F; If follows tho.t \Y is lr." Argument-" of the form "If p, then q; and p; therefore q " are perfectlv valicl, though they may have false premises ancl for this reason fail to be sound. It is the latter form only which figures in rny ti'eatment of the cosmologieal argument. Since oul concern of ihe moment is rvith the validitv of the form of the argriment, not with its soiintlness, consider once more the farrn of each of the following ver.qions of the co,qmological argument. The,*e arguments have the .qame form as each of my examples in my earlier article. (1) If ea,ch of the parts of nature is contingent, the whole of nature is contingent. Each of the parts of nature is contingent. Therefore, the rvhole of nature is conting'ent. (2) If each of the parts of nature did not always exist, then the v;hole of nature did not always exist. Each of the parts of nature did not always exist. Therefore. the whole of nature did not ah,vays exist. If it is too enthymematic to attribute (1) and (2) to St. Thomas himself, then let us evaluatc them on their own merits. Whether 120 Rern B. Ed,wards he saitl it or not, we certainiy have aalid cosmological arguments here, even if we are unable to identify them a.s sou,nd due to the presencc of false or questionable premises. But lldwards has not given any convincing reason why the Third \Ya-v shoukl be regarded as a special case. The reason he offer:s is that the lirst premiss above (which he takes Aquinas to have tacitly assumed) is true in experience. r'Experience does not show us a whole which aluaEs existed even though eaeh of its parts did not always exist." Certainly, experience does not shorv us of any whole that it alwags existed. Corrsequently, statements about such wholes cannot be empiricaily confirmed or disconfirmed. But surely the absence of diseoufiruration eannot be taken as confirmation in a ease like this ! 5 \\'e should carefully note that rve are no longer deilating the question of the aalidity of the argument-forms offered", and" have tnrnerl to the question of the trutlt, of the premises. I mad.e no attempt to defend the second premises of my cosmological arguments in my earlier article, though I hoped to stimulate others more knowledgeable than I about such matters to debate tire issue. Ilowever, I did commit myself to the claim that experience seems to confirm the truth of the flrst premises as I stated them. }[autrrer's rejoinder is that such premises are not empirical, being neither verifiable nor falsifiable. Let us no'iv turn to such matters. 'Ihere are many Thomistic scholars who suspect that St. Thomas made a mistake in introclucing the " time " argument as an integral part of his " contingency " argument, for (2) begins to look like a philosophical proof for the creation of the spatio-temporal universe er nih,ilo, a proof which elsewhere he declines to give on the grounds that reason cannot tlisprove the Aristotelian doctrine of the aeveternity of the world (the co-existence of some ingredient or state of the world with God throrighout an infinite past). That is, he usually doubted that u'e could establish the truth of the second premise of (2) abor.e, though he seems to argue for its truth in the " thircl way " on the ground.s that in an infinite amount o{ time, all possibilities, including the one expressed in the second premise of (2) above, would be actualized. Ilowever, he also insi,qted that his proof of the contingency of the world of nature as a whole is sound even if that world is in some sense everlasting. In other words, he held that both premises of argument (1) are 6 lbdd. 'l'ha Validity of Aquinas' Third Woy LzL true and cau be known to be true even if the truth of the second premise of argument (2) cannot be demonstrated by reason, and must be believed only on the basis of reveiation. I am also suspicious in some ways about (2), and, am inciined to regard (1) as a logically independent version of the cosmological argument the soundness of which is highly defensible. I did say in my earlier article that I regarded- " If all the parts of a whole did not always exist, then the whole itseif did not alwavs exist " as true becuusa erTterience does not present us rvith any 'whoies which always existed even though each of its parts did noi aiways exist; " that is, because experience presents us with no instances in r,vhich the antecedent of this hypothetical assertion is true and the consequent is false. trn the context of the " third way," another way of saying the same thing is that " if all of the parts of nature at some time did not exist, then the whole of nature at some time dicl not exist." Again f would hold that we are conlironted in experience with no cases in rvhich the antecedent is true and the consequent is false. But the reason for this, as Nlautner iusists, may be that neither the antecedent nor the consequent is an empirical assertion, subject to confirmation or disconfirmation by experience. And there are two quite distinct charges involverl here, first that the assertions are not empir.ical at all, and seconclh' that experience fails to show them to be true, that the assertions ar:e rreither verifiable or falsifiable nor verifled or faisified. Concerning the scope of the concept of the 'empiricalr" even the experts are not inclined to agree; but f suspect that serious difficulties rv'oulcI ensue if one classifles as " non-empirical t' uoy statement whose contradictory, or contrary can be confirmed. or clisconfirmetl by experience. The time factor becomes important in a few specially interesting c&ses, because our t'three score years antl ten " vill not allow us to be around long enough to confirm or disconfirm them, though it often cloes permit us to confirm or" disconfirm their contraclictories or contraries. For example, most of us would regard " some men are not mortal " as empirical despite the fact that we would have to be arouncl forever to confirm it, ancl we generally regard it as false because experience seems universally to confirm its contradictory, " a1l men are mortal " and io clisconfirm its contrarv ('f{o men are mortal." Mautner maintains that my first premise in (2) is non-empirical, i. e., neither confirmable nor confirmed, because t'experience cloes 122 Rem, B. Edwards rrot show us of any whole that it alwuys existecl." I submit that this is not because the expression is non-empirical. This expressioti is equivalent in meaning to " l{o whole ahvays existed," ancl thi-" ri.ould be contraclicterl by " Sorne whole has alwalrs existeil," which stiil looks non-empirical, in the same deceptive way in which " Some men are notmortal" at lirst mav strike us as non-empilical. lt has as its contlary " ail ryholes have trlwavs existedr" rvhich is contlaclicted by " Some u'holes haye not ahval's existedr" and thie is clearlv confirmahle and al,qo well coniirme,.l in e:rperience. Thei't: is birth and cleath, .seneration arrrl coruuptiorr. This implies the falsity of " a.11 wholes har.e always existed." 'Ihe problem is, can the contrary of arr obviou.sly ernpirical proposition llajl to be an empilical proposition ? \\'l,at it there is overwhelining empiricai eviclence for the contraly ? I\'hat if everv rvhole gir.en to us in experience has not ahvays existecl, i. e., has come into being at some definite point in the past ? Th:ls certainly seems to be the case. Somethints YerY much like this ruaY be the ca.qe u,ith the antecedent of " If all the parts o{ naiure at some lime did not exist, then the whole of nature at scme time c1ic1 not exist." l,trre certainlv have uot expericncecl a pai-t of nature which at sorle time ciid not exist. This is not becau."e the assertion is non-empirical. Rather it is because the assertion that " all the parts of natrile at some time diil not e-xist " is not onl;. gsrlirmable but al-"o js so u,e1i confirmecl in experience-in sonrething like the wa_y in rvhich " all men are rnortal " is cc.nfirmable and well conlirmed in experience. True, we have not litcrallv experiencecl all tlie parts of natru'e, but we have not litela1.lv expelienced all men either. \,rerv few universal affirmntir.e propositions of this scope are susceptible l,o conclusi,ua confirmation. .\1i we can sav is that as far as erperierrce tal<es us, this seems to be the case, ancl rve have no goocl reason for expecting otheryise. ,\t least 'r,r,-c kno.u, that experience is relevant and that all of it seems to be on one sicle rather than the other of this issue. '.1'o sav that we have not, experienced a part of rrature t'hich at some tinre diri not exist is not to sav that experience can neither confirm nor disconfirm rvhat we sav. Ilather, it is to claim, correctlv, that experience universally confirms the contradictorv assertion that all the parts of nature at some time clid not exist, to -rav notiring of the subalternate claim that some parts of nature at some time ditl not erist. Erperience fails to confirm the contrarv assertion that uo part of natnre at some time dicl not exist. To put the 'l'h,e trrulidit'y of Aqu,i,nas' Third Wuy 723 point another rvay, the claim that " some part of nature alwa;'s êxisted " is experientially false becarlse expef ience so universally con{irms the coutradictorv ciaim that " }Io part of nature always existedr" or thc, equivalent claim that " each part of nature did not always erist." \,[e have experiencecl no part of nature which always e:iistecl preciselv because every part of nature u'hich 'we have experiencecl has not ahvays existed but has conie into being at some definite point in tirne. .\-c St. Thomus -\quinas t,eli. I<uer, , e:rperietrce sliows Lls that many things are sul-rject to l.rirth arrci deathg-enelation ancl col'Luption. Ilorses, lrren, planets, solar svsfsmg-all are exampleri as far i1s we can tell. hr otlttr words, erxperience well confirrns the proposition " Sorne parts of nature have not always exjsted." Tire trutir of this propo.rition implies the falsitv of the contradictory claim " AIl parts of nature have always existetl." This universal proposition i,s, in tuln., the contrary of " .'do part of nature ha-q alwavs existed;" and even though its truth value is undetermined. on the basis of logic alone, it is not ttndeterminecl on the basis of experience. No experiencecl parts of rrature have alwal.s existecl, anc'[ we have experienceil marrv, many sucrir parts of nature. t\11 men are moltal, antl experience htrs agaiu ancl again conflnned it. All pai't-s of rrature Jrave corne into being at some clefinite time in the past, and experience has again and again confirmed it-not concltisively. to be sure, for we hat,e not experienced literallv all the parts of nature aD). more than we hat-e experienced ali men. But it is about as well conlirmed as a universtrl affirmative propositiorr of this scope ever gets. " Some rneu are not rnortal " iacks conflrmation because its contradictorf is so 'n'e11 confirmecl, though not conclusively confinned. So it is at..o with " Sorne parts of uaturrr have alwtrvs existetl." T thus conchicle tlrat experietrce plovicles us rvith every gooci leasorl to believe that if e ach of the parts of nature clid not alwal s erist, theii the rvhole of nature clid not alwavs exist. Grantecl that our experience is limited, it is nevertheless about all that rvu have to go on in .*uch matters. r\s far as it will take us, experiencc rloes show that each of the parts of nature did not ahva_ys exist. anc-[ it further shows us that if an5' r,vhole is composed of parts which originated ai some point in time. then the whole itself oliginatecl at some point in time. Thus we cannot find a whole which always existed, but each of whose parts did not alwavs exist. 124 Rem B. Dd,ward,s Y.ry similar consideratious apply when we turn to 1), the contingency argument. I regard this as the strongest version of the cosmological argument. for it does not depend for its sounchress upon the uon-existence of nature at sorne point in the finite past and thus may avoicl the paradox of " a time when there was no time." Experience does seem to show ihat if each of the parts cf any whole is contingeut, the whole is itseif contingent. To claim at ihis point that nature as a whole is an exception to this would be merely to beg the question, and as far as experience takes us ii d.oes seem that each of the parts of nature is eontingent. fn saying that they are contingent, we mean that they are capable of nonexistence aucl depencl upon something other than themselves for their existcnce. Contingent things might or might not be, and if they are at all, their being is not a self-sufficient form of being. r\gain, all the things given to us in experience cio seem to be contingent in just this sense. " Ail the parts of nature are contingent," is well confirmed" as far as experience will take us. Once more, we clo not have much else besides experience to go on iu such matters. even if conclusive confirrnation is lacking. Certainly the contrary assertion that " No part of nature is contingent " is falsified, for experience conflrms its contradictory " Some part of nature is contingent." Remember again our encorlnters with birth and death, generation and" corruption. Experience fails, to conflrm " Some part of naiure is not contingent," not becau-qe this is not an empirical proposition, but because its contradictorv " AII parts of nature are continsent " is so 'well confirmed. In the same sense, experience fails to confi.rm tt Some men are not mortalr" not becausc it is not an empirical proposition, but because its contradictory " r\II men are mortal " is so rveli confirmed. ff experience does not acquaint us with an,r' non-mortal humans. this is because ir does acqttaint us with so very many mortal humans. Similariy, if experience fails to acquaint us with some part of nature which is not contingent, it is because it cloes acquaint us with so very manv parts of nature which are contingent. Where shall we {incl an exceptiori ? Furthermore, experience also shows that if any whole is composecl entirely of corrtingent parts, then the whole itself is contingent. As far as experience will talre us, we thus have every good reason to believe that if nature as a whole is composecl entirel-v of eontingent parts, it is itself contingent. Tn one sense, of course, we clo not know that there are no necessary parts of natnre, for wc 'l'he Valid,ity of Aqui'nas' Third, WoA 125 have not experienced. them all. " Al1 parts of nature are con' tingent " is not conclusi,aely verifled. Some philosophers, such as the Greek atomists, were confldent that some parts of nature (tht: atoms) were necessary, i. e., incapable of not existing and possessing' a self-sufficient form of existence. Since there is now no good reasor for thinking that such claims are non-empirical, even modern claJ' philosophers might profitably turn to the question of whether they are true. What light cloes the splitting of the atom shed upon -*uch problems ? I hope that someone more knorvledgeable than I about such matters will take up the issue and enlighten us. W'here shall we turn in the macrocosm or microcosm to find a part o.t nature which is not contingent ? I suspect that we have not founri and will not find one, and that the proposition " a1l of the parts of nature are contingent " is tme. As to wholes which exist permanently (relatively), experience, on the contrary, d,oes show us tha,t their parts need not exist permanentll'. Take for in-qtanee rouncl-the-eloek pop-music broadcasts.B I must say that I fail completely to see the relevance of this final remark unless it is here being assumed that even if an argument does not commit the faliacy of composition, at least it must commii the fallacy of division. Nowhere do I even hint at the suggestion that each part of some whole must possess the properties possessed by that whole, and I certainly clo not argue that each of the parts of nature must be permanent since the whole of nature is perrnanent. Arguments from whole to part, commonly recognized. as t'divi- ,qion " argument, D&y also be treated as enthymemes however, having a perfectly valid argument form. They may be regarded as havius the form tt lf a whoie possesses a certain property, then cach of its parts possesses that property; and a whole possesses a certain property; therefore each of it parts possesses that property." 'Ihere may actually be sound, argumcnts of this form, if some such arguments have all true premises as well as a valid form. What then would be wrons with the following argument ? " If a whole concert is (relatively) permanent, then eacir of its parts is (relativeiy) permanent; and the whole concert is (relatively) p.rmanentl therefore each of its parts is (relatively) permanent. 6 rbid. 126 Rem B. Edwards (\\re might produce an analogous argument suffering from none of the ambiguities of " is [relatively] permanent " by substiiuting " lasts exactly one hour " lyherever this appears. ) This argument is perfectiy vaiitl in form, but it oloviously does not prove the trutir of its conclusion. Why not ? Because this valid argument has at least one false premise. Ilxperience cloes shoru us many cases rvhere th,-: antecerlent of the first prcmise is tme and the consequent is false. Since Mautner gives us no clues for clistinguishing premises frorn conclusion in his exarnple, perhaps he does want the argument to nin the otiier rvay after all, i. e., from parts to 'whole, and thus be a " cornposition " argument. 'Ireatetl as an eniliymeme, this woulcl be: " If each of the parts of a concert is impermanerit (or lasts one hour), then the rvhole concert is imperrnanent (or lasts one hour) ; nncl each of the par"ts of a concert is impermanent (or lasts one hour) ; t'h,erafore the wirole concert is impermanent (or iasts one hour)." Now this is again a perfectly valicl argument. Its only fault :ls that its fir.st l,remise is false, since we do find. in experience that tire parts of <-rur concert last an hour each antl that the whole lasts all night, or howet er long pop concerts usually run. Uni,uersitg of Terunessee, Kno a oill, e, T enn es s e e.