Belief is Not the Issue: A Defence of Inference to the Best Explanation

8/14/2019 Belief is Not the Issue: A Defence of Inference to the Best Explanation

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Belief is Not the Issue:

A Defence of Inference to the Best Explanation

Gregory W. Dawes

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Belief is Not the Issue: A Defence of Inference to the Best Explanation,

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Abstract

Defences of inference to the best explanation 7IBE8 fre9uently

associate IBE with scientific realis", the i!ea that it is reason-

able to belie0e our best scientific theories$ I argue that this

lin2age is unfortunate$ IBE !oes not warrant belief, since the

fact that a theory is the best a0ailable explanation !oes not

show it to be 7e0en probably8 true$ hat IBE !oes warrant is

acceptance: ta2ing a proposition as a pre"ise in theoretical

an!#or practical reasoning$ e ought to accept our best sci-

entific theories since they are the theories that are "ost li2ely

to lea! to the goal of science, which is that of 2nowle!ge$ In

support of this clai" I in0o2e Bill 3ycan6s ;anglossian reflec-

tions regar!ing


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Introuction

A fre9uent pattern of reasoning, both in the sciences an! in e0ery!ay

life, is that 2nown as =inference to the best explanation6 7IBE8$

>ere6s an e0ery!ay exa"ple$ =I hear a scratching in the wall, the pat-

ter of little feet at "i!night, "y cheese !isappears ? an! I infer that

a "ouse has co"e to li0e with "e6$Each of these pheno"ena ? the

scratching, the patter, the !isappearance of the cheese ? coul! ha0e

another explanation$ There "ight e0en exist a single, alternati0e ex-

planation that co0ers the" all$ But for a 0ariety of reasons, such as

si"plicity, econo"y, an! plausibility, the "ouse hypothesis see"s to

be the best$

>ere6s another exa"ple$ In %@.+ /harles Darwin publishe! On

the Origin of Species by Means of Natural Selection$ In that wor2 he

cites a 0ariety of pheno"ena ? the geographical !istribution of spe-

cies, the existence of ho"ologous anato"ic structures an! 0estigial

organs, the rese"blance of e"bryos of !iffering species, an! the

fossil recor! ? an! suggests they are better explaine! gi0en his the-

ory of natural selection than on the alternati0e 0iew of special cre-

ation$ >is conte"poraries woul! ha0e !escribe! this as a =consilience

of in!uctions6, in which a range of !ifferent pheno"ena are seen to

be explicable by reference to the one causal principle$But particu-

larly since Darwin was contrasting this potential explanation with

another ? that of special creation( ? it is "ore helpfully 0iewe! as an

inference to the best explanation$

1ince this pattern of explanation was gi0en its "o!ern na"e by

ilbert >ar"an in %+).,. its significance has been !ispute!$ ust

what, if anything, shoul! be the conclusion of an inference of this

Bas /$ 0an Craassen, The Scientific Image /laren!on 3ibrary of 3ogic an!

;hilosophy 7xfor!: /laren!on ;ress, %+@&8, pp$%+?&$

ohn 3osee, A Historical Introduction to the Philosophy of Science r! e!i-

tion5pus Boo2s 7xfor!: xfor! ni0ersity ;ress, %++8, p$%$

( Neal /$ illespie, Charles Darin and the Problem of Creation7/hicago:

ni0ersity of /hicago ;ress, %+*+8, pp$)*?@%$

. ilbert >$ >ar"an, =The Inference to the Best Explanation6, The Philo!

sophical "e#ie*( 7%+).8, pp$@@?+.$

!


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2in!F Does the fact that so"ething is the best a0ailable explanation

gi0e us a!e9uate reason to belie0e in the existence of the entities

that it "entionsF r shoul! we withhol! belief, since the explanation

in 9uestion "ay be nothing "ore than =the best of a ba! lot6F )In!ee!,

is there any 0alue in this line of reasoning at allF Is it, perhaps,

nothing "ore than a !resse!-up 0ersion of the fallacy of affir"ing

the conse9uentF

A notable feature of these !iscussions is that theyare associate!

with wi!er !ebates regar!ing scientific realis"$ Do we ha0e a!-

e9uate reason to regar! our best scientific theories as 7approxi"ately

or partially8 true, e0en when they spea2 of entities we coul! ne0er

obser0eF r shoul! we conclu!e "erely that our best theories are

=e"pirically a!e9uate6, offering a correct account of the obser0able

regularities of our worl!F As it happens, "ost !efen!ers of IBE ha0e

been scientific realists, who refuse to belie0e =that a false theory

woul! explain, in so satisfactory a "anner G se0eral large classes of

facts6$*


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portant issue, as far as IBE is concerne!, is not whether we ha0e a!-

e9uate reason to belie#ea theory, but whether we ha0e a!e9uate

reason to accept it$ Acceptance, I shall argue, will often go han!-in-

han! with belief, but it nee! not !o so$ Nor is it i"portant that it

shoul!$ It is sufficient for the progress of science, that scientists

shoul! accept the best a0ailable explanation, whether or not they

happen to belie0e it$


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"eans to accept a proposition "a2e acceptance in!istinguishable

fro" belief$ D$ 1$ /lar2e, for instance, insists that acceptance actu-

ally entails belief, but assu"es a broa! 0iew of acceptance that I

shall shortly re'ect$%& 1i"ilarly, ;aul >orwich argues that accept-

ance is functionally i!entical with belief, but assu"es an instru-

"entalist 0iew of acceptance ? =belie0ing 'ust the obser0able con-

se9uences of a theory6%%? that I also re'ect$ ne can also !efine belief

in ways that un!er"ine this !istinction$ >er"an !e Hegt, for in-

stance, !efines belief as =a !isposition to act6$%But if one !efines be-

lief in ter"s of a !isposition to act, then it is practically in!istin-

guishable fro" what I shall call =acceptance6$

1.1 Assu$ptions %egaring Belief

1o what I nee! for the purposes of "y argu"ent is a wor2able

concept of acceptance$ I shall spen! little ti"e on what I "ean by be-

lief$ I a" assu"ing that to belie0e so"ething is to consi!er it to be

true, the =so"ething6 here being concei0e! of as a proposition, an ut-

terance, or so"e other bearer of "eaning$ n!erstoo! in this way,

belief is not to be thought of as a !isposition to act, nor e0en as a !is-

position to assert$ It can be !efine! as a !isposition, but its "ost

characteristic feature is a ten!ency to experience a certain 2in! of

"ental state$ Belief is, as 3$ onathan /ohen writes,

a !isposition, when one is atten!ing to issues raise!, or ite"s re-

ferre! to, by the proposition that p, nor"ally to feel it true that p

an! false that not-p, whether or not one is willing to act, spea2, or

reason accor!ingly$%

%& D$ 1$ /lar2e, =Does Acceptance Entail BeliefF6, American Philosophical

)uarterly% 7%++(8, pp$%(.?.., at p$%(+$

%% ;aul >orwich, =n the Nature an! Nor"s of Theoretical /o""it"ent6,

Philosophy of Science.@ 7%++%8, pp$%?%(, at p$$

% >er"an /$ D$ $ !e Hegt, =To Belie0e in Belief: ;opper an! 0an Craassen

on 1cientific Healis"6, *ournal for +eneral Philosophy of Science , -eits!

chrift f.r allgemeine /issenschaftstheorie* 7&&)8, pp$%?+, at p$$

% 3$ onathan /ohen,An 0ssay on (elief and Acceptance 7xfor!: /laren!on

;ress, %++8, p$($

&


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A person who has such a !isposition will, if she is acting rationally

an! has no reason to !o otherwise, be incline! to act in ways that are

consistent with her belief$ 1he will also be incline!, other things be-

ing e9ual, to assert the truth of that which she belie0es$ 7Belief can

be regar!e! as a comple1!ispositional state$8 But belief, as I un!er-

stan! it, shoul! not be definedin ter"s of a !isposition to act or to

assert$ After all, one coul! ha0e a !isposition to assert por to act as

if pwere true, without belie0ing thatp$ ne coul!, for instance, be

!isse"bling, "erely preten!ing to belie0e$%(

1.! A Broa Definition of Acceptance

=Acceptance6, howe0er, is not so easily !efine!$ The proble" here is

that the ter" is so"eti"es use! in a broa! sense, which !istin-

guishes acceptance an! belief so sharply as to !eny that there is any

relation between acceptance an! truth$ An!rei Buc2areff, for in-

stance, spea2s of =non-!oxastic acceptance6, an! argues that while

=belief ai"s at truth, G acceptance ai"s at utility or success6%. >e

also argues that while beliefs are such that they ought to for" a co-

herent set ? new beliefs a!!e! to the set shoul! be consistent with

the ol!%)? acceptance is not sub'ect to such a constraint$ %*But on "y

0iew of acceptance, acceptance has truth rather than so"e other

2in! of utility as its ai" 7see %$8 an! the propositions that we accept

ought 7at least i!eally8 to be consistent with one another 7see $%8$

3$ onathan /ohen6s !efinition of acceptance is also broa!er than

the one I wish to e"ploy$ =To accept thatp6, /ohen writes,

is to ha0e or a!opt a policy of !ee"ing, positing, or postulating

thatp? that is, of going along with that proposition 7either for the

long ter" or for i""e!iate purposes only8 as a pre"iss in so"e or

all contexts for one6s own an! others6 proofs, argu"entations, in-

%( Alston, =Belief, Acceptance, an! Heligious Caith6, p$*$

%. An!rei Buc2areff, =Acceptance Does Not Entail Belief6 International

*ournal of Philosophical Studies%@ 7&%&8, pp$..?)%, at p$..$

%) Engel, =Intro!uction6, p$$

%* Buc2areff, =Acceptance Does Not Entail Belief6, p$..$

'


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which scientists accept the best a0ailable explanation of so"e puKK-

ling pheno"enon$ hether or not we ha0e a!e9uate reason to re-

gar! any scientific theory as true, the sciences !o see" to ha0e as

their goal the pursuit of 2nowle!ge, which 7at least on any tra!i-

tional account8 entails truth 7see 1ection 8$ If this is correct, then a

conception of acceptance that !oes not ha0e truth as its ai" will be

inappropriate$&

1." Acceptance with the Goal of )nowlege

Cor this reason, I shall a!opt a narrower !efinition of acceptance,

which doesha0e a relation to what see"s to be the goal of the sci-

ences$ The first part of "y !efinition rese"bles that offere! by /o-

hen: to accept a proposition is to e"ploy it as a pre"ise in one6s reas-

oning, whether theoretical or practical, in any !o"ain to which it

"ight apply$ But it a!!s a con!ition that I ha0e ta2en fro" the wor2

of Jeith 3ehrer$ Acceptance, argues 3ehrer, is to be !efine! by refer-

ence to its purpose or goal$ An! the goal or purpose of acceptance is

that of =attaining truth an! a0oi!ing error with respect to the 0ery

thing one accepts6$%1o, on "y 0iew, to accept a proposition is to em!

ploy it as a premise in one2s reasoning& hether theoretical or prac!

tical& in any domain to hich it might apply& ith the goal of attain!

ing 3noledge4

It follows that the person accepting a proposition, in this sense,

an! the person belie0ing it ha0e the sa"e goal$ They are both ai"ing

at 2nowle!ge, which entails truth$ The !ifference is that the person

belie0ing a proposition assu"es ? howe0er pro0isionally an! with

!ue 9ualifications ? that she has attaine! that goal$ After all, that is

what belief "eans: it "eans hol!ing so"ething to be true$ But to ac-

cept a proposition is not to assu"e that the goal has been reache!,

since one can accept a proposition without belie0ing it, e0en pro0i-

& ne can !escribe this 0iew of science as =axiological realis"6$ It hol!s that

scientific theories ai" at truth, whether or not we ha0e any reason to be-

lie0e they ha0e achie0e! their ai"$ 1ee Ti"othy D$ 3yons, =Towar! a

;urely Axiological 1cientific Healis"6, 0r3enntnis) 7&&.8, pp$%)*?&(, at

p$%)*$

% Jeith 3ehrer, Theory of 5noledge n! e!ition 7Boul!er, /: est0iew

;ress, &&&8, p$%$

*


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sionally$In accepting a scientific theory, one "ight e0en hope that

it is true5 one "ight hope that on this occasion the goal of 2nowle!ge

has in fact been reache!$ But the act of accepting the theory !oes not

co""it one, e0en i"plicitly or tentati0ely, to the i!ea that it has$

E0en on this narrow !efinition of acceptance ? ta2ing to be true in

the course of one6s reasoning with the goal of attaining 2nowle!ge ?

acceptance re"ains !istinct fro" belief$ In particular, acceptance 7as

I un!erstan! it8 !oes not entail belief$Cro" =Saccepts thatp6 one

cannot 0ali!ly infer that Sbelie0es thatp$

>ere6s an exa"ple$( /onte"porary physicists generally accept

the theory of 9uantu" "echanics !e0elope! in the %+&s by Erwin

1chrL!inger, erner >eisenberg, an!


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ies, the situation is "ore co"plex$ There are at least two proble"s

here$.The first is that scientific theories co""only in0ol0e i!ealiKa-

tions or approxi"ations, which woul! be true only un!er con!itions

that !o not actually obtain$ 1urfaces are treate! as though they are

frictionless, e0en though no such surfaces exist$ Clui!s are treate! as

though they were continuous, e0en though they are "a!e up of !is-

crete "olecules$ An! so on$ ne can accept a scientific theory as a

whole, e0en though one recogniKes that so"e of its assu"ptions are,

when ta2en at face 0alue, false$)

A relate! proble" is that scientists "ay accept, in the sense of

choosing to wor2 with, a theory that has at least one in!isputably

false obser0ational conse9uence$*In this situation, the theory can-

not be true, at least as it stan!s$ It "ay, of course, be partiallytrue,

in the sense of "a2ing true pre!ictions within a certain !o"ain, un-

!er certain con!itions, or as a li"iting case$ @But it cannot be re-

gar!e! as true tout court, that is to say, without so"e such 9ualifica-

tion$ In these circu"stances a scientist will be reluctant to say that

he or she belie#esthe theory$+But she "ay consi!er herself to ha0e

excellent reason to accept it$

1uch cases pro0i!e further e0i!ence of the nee! to !istinguish be-

lief an! acceptance$ But they !o not un!er"ine the i!ea that the ac-ceptance of scientific theories has 2nowle!ge as its goal$ A scientist

"ay a!"it that partial truth "ay be the best we can achie0e at the

. In fact, there exists a thir! proble", which has to !o with the acceptance of

inconsistent theories, but I shall !eal with that shortly 7$%8$

) I a" grateful to 3ucy eston-Taylor for re"in!ing "e of this$

* I a" grateful to an anony"ous referee for !rawing "y attention to this

fact$

@ Alan


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present "o"ent or that an i!ealiKe! law ? such as one that ignores

friction ? is the best way of wor2ing towar!s successful pre!ictions$

But this !oes not "ean that she has aban!one! goal of =attaining

truth an! a0oi!ing error with respect to the 0ery thing Mshe

accepts6$&alileo alilei see"s to ha0e been the first scientist to

propose laws of "otion that ignore! 7for the "o"ent8 =the resistance

of the "e!iu"6$%To accept such laws is not to aban!on the goal of

truth: alileo, after all, 0igorously re'ecte! instru"entalist inter-

pretations of science$It is to recogniKe 7as he !i!8 that the path to

that goal "ay be in!irect$

! Inference to the Best Explanationhat, then, can we "a2e of inference to the best explanation 7IBE8F

I shall begin with a pro"ising account of IBE, which fran2ly ac-

2nowle!ges the non-realist6s ob'ection$ It hol!s that although the

fact that so"ething is the best a0ailable explanation !oes not show it

to be 7e0en probably8 true, it !oes "a2e it reasonable for us to be-

lie0e it$ I shall then set out "y own 0iew, by way of contrast$ It will

!iffer in two respects$ Cirst of all, it will suggest that IBE warrants

acceptance rather than belief$ 1econ!ly, it will set out this conclu-

sion in ter"s of an =ought6$ Hather than saying that it is reasonable

to belie0e the best a0ailable explanation, it will argue that we ought

to accept it$

!.1 IBE an Belief

In the context of a 0igorous !efence of scientific realis", Alan


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he calls ='ustificationis"6, the 0iew that =a 'ustification for belie0ing

"ust be a 'ustification for the belief6$The 2ey !istinction here is

that between the act of belie#ingan! the content of the belief$


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ance$ The response recogniKes the 0ery !istinction between belief

an! acceptance on which "y argu"ent rests$ The sole !ifference in

the case of inconsistent theories is that one accepts the theories in

the hope that one !ay the inconsistency will be resol0e!$

!.! IBE an Acceptance

>ow, then, !oes "y 0iew of IBE !iffer fro" that offere! by


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see"s to be re9uire! when a theory hasbeen i!entifie! as the best

explanation$ In such circu"stances, the scientist is not "erely per!

mittedto accept it5 she oughtto !o so$

hat 2in! of an =ought6 is thisF There are se0eral possibilities$ In

a !iscussion of the ethics of belief, Hichar! Cel!"an argues that the

=ought6 in such !iscussions is best regar!e! as a role ought$@ It is

co"parable, in this respect, to the =ought6 in the sentence, =A goo! pi-

anist ought to be able to play Beetho0en6s


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ciple of practical reason: it hol!s that if we are co""itte! to a goal,

then un!er pain of practical irrationality, we are also co""itte! to

the best "eans of attaining that goal$ An! the reasons why we

shoul! accept the best a0ailable explanation are prag"atic: they

ha0e to !o with a!opting the best a0ailable "eans to an en!$

As I suggeste! earlier, one of the proble"s facing !efen!ers of

IBE is that it is notoriously !ifficult to establish a lin2 between ex-

planatory 0irtues an! truth$ Nor are we "uch further ahea! if we

argue 7with


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e can explain our preference for these rules by assu"ing, for a

"o"ent, that we were !esigne! by =a s2illful an! bene0olent is tal2 of a bene0olent "other nature is "erely a

!e0ice$ It "ay be regar!e! as a fanciful way of !escribing the effects

of natural selection, but it nee! not be so regar!e!$ E0en if it were

entirely a fiction, it woul! highlight so"e i"portant facts about the

utility of theories that !isplay these explanatory 0irtues$ 1uch theor-

ies, it suggests, ha0e features that can ai! us in our search for the

truth$ If truth is our goal, we shoul! prefer those theories that are

si"ple, ha0e great explanatory power, an! are testable, co"prehens-

i0e, an! consistent with what we alrea!y 2now$3ycan rightly argues that such features !o not gi0e us a!e9uate

reason to belie0e that a theory will be true, or e0en probably true$

But they can pro0i!e us with a !efence of IBE, if we un!erstan! IBE

as warranting nothing "ore than acceptance$ I ha0e argue! for a

( 3ycan, *udgement and *ustification, p$%(&$

(( 3ycan, *udgement and *ustification, p$%($

1(


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0iew of acceptance that has truth, or 7"ore precisely8 2nowle!ge as

its goal$ hat 3ycan6s ;anglossian reflections show is that theories

exhibit these features are "ore li2ely to bring us to our goal$ They

are the theories that are "ost li2ely to contribute to the growth of

our 2nowle!ge$ This is not a reason to belie0e such a theory, but it is

a reason to accept it, at least until a "ore satisfactory theory

e"erges$

At this point, a rea!er "ight ob'ect that I ha0e fallen bac2 into

the 0ery prag"atic notion of acceptance that I pre0iously clai" to

ha0e re'ecte!$ The ob'ection is un!erstan!able$ There is asense in

which acceptance, as I un!erstan! it, is "oti0ate! by prag"atic con-

si!erations, for the consi!erations that weigh in fa0our of IBE are

in!ee! prag"atic$ hat is i"portant is that it is a prag"atis" that

is narrowly focuse!: it has 2nowle!ge, rather than so"e other 2in!

of utility, as its goal$ hen we accept a theory, it is because it is

li2ely to lea! us closer to this goal$ 1o unli2e Buc2areff an! /ohen, I

ha0e not se0ere! the lin2 between acceptance an! truth$ The fact

that a theory is the best a0ailable explanation "ay not gi0e us a!-

e9uate reason to regar! it as true, but if our goal is 2nowle!ge 7an!

therefore truth8, it !oes gi0e us excellent reason to accept it$

It follows that "y 0iew of scientific theories is not =instru"ental6in the tra!itional sense$ It !oes not regar! a scientific theory as co"-

parable to a tool, such as a ha""er, which in no sense =represents6

the things it pro!uces$(.E0ery analogy li"ps, but we "ight say that

on "y 0iew, a!opting a theory "ore closely rese"bles choosing the

best route up a "ountain$ If our ai" is to reach the su""it, we are

acting rationally in choosing the route that see"s "ost li2ely to ta2e

us there$ In!ee! on pain of practical irrationality we oughtto choose

the "ost li2ely route$ But the route is itself part of the "ountain

an!, for all we 2now, once we ha0e reache! the top of this particularpath, we "ay be at the su""it$

(. Ernest Nagel, The Structure of Science' Problems in the $ogic of Scientific

01planation 73on!on: Houtle!ge an! Jegan ;aul, %+)%8, p$%&$

1*


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onclusion

e are not, I ha0e argue!, warrante! in belie0ing a theory ? in hol!-

ing it to be true ? because it is the best a0ailable explanation$ But

the fact that it is the best a0ailable explanation "eans that we ought

to accept it: we ought to ta2e it as a pre"ise in our theoretical an!

practical reasoning in any !o"ain to which it applies, whether or not

we happen to belie0e it$ The reasons for this are prag"atic$ A theory

that !isplays the 9ualities that we tra!itionally 0alue ? such as si"-

plicity, explanatory power, a high !egree of testability, an! consist-

ency with what we are alrea!y belie0e ? is li2ely to be a useful tool

in the tas2 of increasing our 2nowle!ge of the worl!$ Do we e0er

ha0e reason to thin2 that our 2nowle!ge of the worl! has been in-

crease!F That is another 9uestion5 the answer "ay be that we !o

not$ But if our goal is 2nowle!ge, then not only is it reasonable to ac-

cept the best a0ailable explanation of any puKKling fact5 we ought to

!o so$

=ni#ersity of Otago& Dunedin& Ne -ealand

gregory4daes>otago4ac4n7

1+
mailto:[email protected]:[email protected]

Belief is Not the Issue: A Defence of Inference to the Best Explanation

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