philosophy of k. popper

8/21/2019 Philosophy of K. Popper

1/19

Some Bibliography

• Popper, K.R. (1935) Logik der Forschung (The Logic of Research) , Vienna: Springer; trans. The Logicof Scientic Discovery , London: !t"hinson, 1959. (#risp and in"isi$e statement o% his "lassi" ideas onphilosophy o% s"ien"e and o% epistemology. &he 'nglish translation "ontains additional material, aseplained in 3.)

• Popper, K.R. (19*5) The Open Society and Its Eneies, London: +o!tledge. ( "riti"al introd!"tion tothe philosophy o% history and o% politi"s that ta-es lato, egel and /ar to tas- %or their anti0demo"rati" and anti0"riti"al tenden"ies.)

• Popper, K.R. (19*a) 2e4 o!ndations %or Logi"6, /ind 57: 193835, 4ith "orre"tions in (19*) 5:798. ( system o% nat!ral ded!"tion.)

•

Popper, K.R. (19*b) 2Logi" pen #o!rt. (&4o $ol!mes,"ontaining opper6s intelle"t!al a!tobiography, 33 "riti"al essays and 2+eplies to /y #riti"s6, as 4ell asa "omplete bibliography !p 193.)


2/19

?arl opper

alsi@"ation, not ind!"tion


3/19

&he roblem o% Aemar"ation

• >ne "entral theme o% opper6s 4or- 4as the problem o% demar"ation,that is, o% telling the dieren"e bet4een s"ien"e and non0s"ien"e.

• Cnli-e the Vienna "ir"le, 4ho so!ght to reDe"t 4hat 4asn6t s"ien"e as(in some sense) meaningless, opper6s position 4as more modest:S"ien"e 4as a game 4hi"h reE!ired that in some spe"i@able"ir"!mstan"es 4e reDe"t a gi$en s"ienti@" theory; other sorts o% theory"o!ld per%e"tly 4ell be meaning%!l, b!t they are not s"ienti@".

• t @rst this 4as a logi"al %eat!re o% the theory8 a s"ienti@" theory m!stha$e impli"ations %or obser$ation, and 4hen o!r obser$ations sho4those impli"ations are %alse, 4e "an reDe"t the theory.

• opper obDe"ted to ind!"ti$ist $ie4s (a""ording to 4hi"h a s"ienti@"theory had to be s!pported by obser$ations) %or t4o reasons: – irst, he arg!ed that it 4as too easy to @nd e$iden"e 2s!pporting6 a gi$en theory.

(ere he !sed eamples %rom re!dian psy"hology, /arist theory and other

pla"es.) – Se"ond, he arg!ed that !me6s "ritiE!e o% ind!"tion sho4ed that 4e simply

"o!ld not a"t!ally s!pport (i.e. gi$e good e$iden"e %or) a general "laim !singe$iden"e %rom parti"!lar "ases.


4/19

/od!s &ollens and /od!s/oron

1. =% & then >

. ot >

3. &here%ore, not &.

Vs.16. =% & then >

6. >

36. &here%ore, &.• (&he polite, oF"ial label %or the se"ond

arg!ment %orm is 2aFrming the"onseE!ent6G)


5/19

=mpressi$e, b!tG

• opper6s inH!en"e on s"ientists6 o4n $ie4s o% their 4or- hasbeen "onsiderable8 perhaps e$en greater than &.S. ?!hn6sinH!en"e.

• is presentation o% s"ien"e as gro!nded in the ongoing testing o% o!r theories and al4ays open to the possibility that they 4illbe re%!ted at the net test, resonates strongly 4ith them.

• hilosophi"ally, his reDe"tion o% ind!"tion allo4ed him to a$oidthe diF"!lties the logi"al empiri"ists str!ggled 4ith in theirattempts to !nderstand "on@rmation.

• B!t the reDe"tion o% ind!"tion also lea$es a maDor gap in his!nderstanding o% s"ien"e8 4e don6t simply regard s"ien"e as a-ind o% intelle"t!al game: 4e !se the res!lts o% s"ien"e to

g!ide o!r practice 4hen 4e are engaged in p!rs!ing o!r ends.B!t 4itho!t some a""o!nt o% ind!"tion, opper6s positionpro$ides no a""o!nt o% ho4 or 4hy 4e sho!ld pre%er to a"t in4ays o!r present 4ell0tested b!t still0standing theories imply4ill be s!""ess%!l.


6/19

AiF"!lties

• opper 4as etremely persistent and st!bborn8 as4ell as $ery demanding o% the st!dents 4ho 4or-ed4ith him.

• is 4or- "ertainly did e$ol$e8 b!t he ne$er b!dgedon any o% his %!ndamental $ie4s, in"l!dingespe"ially the "omplete reDe"tion o% ind!"tion.

• e did attempt to "apt!re some sense o% progress%or s"ien"e in terms o% a""o!nts o% the tr!th0"ontentand E!estion0"ontent o% theories, b!t these notions4ere al4ays !ntenable, and did nothing to resol$e

the la"- o% any "ommitment to ind!"tion.• e did some inH!ential 4or- on probability theory,

in 4hi"h "onditional probabilities (rather thanabsol!te probabilities) 4ere ta-en as primiti$e.


7/19

p!IIle abo!t ind!"tion

• &here is something odd abo!t !me6s (and opper6s) "ritiE!e o%ind!"tion and its relation to the modest attit!des o% s"ientiststo4ards e$en their most s!""ess%!l theories.

• >n one hand, it is "lear that (%or eample) despite its many brilliants!""esses, e4tonian physi"s has t!rned o!t to be %alse.

• &he history o% s!"h %ail!res sho4s s"ientists sho!ld do!bt that their

present theories are tr!e.• B!t their modesty is not a %orm o% !mean s-epti"ism8 4here a

theory @ts a large "olle"tion o% 4ell0established %a"ts, 4e don6tepe"t similar obser$ations to !ndermine the theory later on.

• &he obser$ations s"ientists are 2a%raid o%6 i.e. the ones they s!spe"tmay lead to tro!ble %or their presently held theories, areobser$ations o% ne4 -inds o% %a"ts: obser$ations o% e$ents at higher

energies, or on smaller s"ales, or o% ne4 phenomena.• B!t a !mean has no more reason to epe"t ne4 phenomena to gi$e

tro!ble than she has to epe"t entirely %amiliar sorts o% "ases to gi$etro!ble8in either "ase, it6s only ind!"tion that s!pports o!r presenttheory, and !me and opper both reDe"t ind!"tion as in$alid(tho!gh !me tho!ght, 4isely, that it 4as also indispensable).


8/19

!rther "onsiderations

• >n the other hand, it may 4ell beind!"tion that leads !s to s!spe"t theoriesare more li-ely to go 4rong 4hen 4e apply

them to ne4 -inds o% phenomena, or ne4etremes o% parameter $al!es.

• Still, p!re ind!"ti$e s-epti"ism li-eopper6s dra4s no line here8 ind!"tion is

in$alid, periodJnot 2>?6 4hen applied to%amiliar "ases and d!bio!s 4hen etendedbeyond them.


9/19

allibilism

• ""epting that o!r theories may 4ell t!rno!t to be 4rong seems reasonable.

• =n %a"t, s"ientists "an sometimes e$enpredi"t, based on their theory, the sorts o%

"ir"!mstan"es in 4hi"h it6s li-ely to %ail ("%.re"ent re$ie4s o% the L# and its li-elyres!lts %or the 2standard model6 in parti"lephysi"s).

•

B!t %allibilism does not imply that 4e ha$eno gro!nds %or a""epting o!r presenttheories8 it only implies that 4e s!spe"t theymay not t!rn o!t to be "ompletely tr!e.


10/19

&r!th and other targets

• &here is something odd abo!t thin-ing in terms o% tr!th here,as 4ell.

• &he methods o% s"ien"e (as opper rightly sa4) "ontin!allyepose theories to %!rther tests8 e$en a theory that is per%e"tlyreliable in the range o% appli"ations 4e6$e already tried "an t!rno!t to be %alse be"a!se it %ails in some ne4 appli"ation.

• erhaps, gi$en the a"t!al re"ord o% s"ien"e, it 4o!ld be 4iser tosay that the goal o% s"ien"e is to a"hie$e greater and greaterreliability and pre"ision in o!r des"riptions and eplanations.

• =n some sense this a"t!ally brings !s ba"- to the idea o% tr!th,b!t in a more reser$ed 4ay: er%e"t reliability and pre"ision isboth something 4e don6t e$er epe"t to a"t!ally a"hie$e, and

etremely "lose to 4hat 4e 4o!ld epe"t (e$en demand) %rom atheory 4e 4o!ld regard as tr!e. >% "o!rse 4e 4o!ld alsoepe"t maimal po4er (i.e. 4e 4o!ld %a$o!r a theory that 4o!ld"onstrain o!r obser$ations more tightly, ass!ming eE!alpe"ision and reliability) be%ore 4e 4o!ld be tempted to spea- o%2tr!th, the 4hole tr!th, andG6


11/19

Sear"hing %or &r!th in all the4rong pla"esG.

• opper6s s-epti"ism abo!t ind!"tion lea$es!s 4ith little gro!nds %or "on@den"e abo!tma-ing progress in s"ien"eJ

• ss!ming e$erything 4or-s 4itho!t a hit"has 4e %alsi%y theories, 4e may be right inreDe"ting one theory a%ter another, b!t

•


12/19

#onDe"t!re and +e%!tation

• &he pattern o% s"ienti@" 4or- on this a""o!nt is$ery simple and repetiti$e:1. s"ienti@" "onDe"t!re is made.

. S"ientists try to re%!te it.

• &he se"ond step is repeated !ntil it s!""eeds.

•


13/19

orms and games

• or opper these are r!les that someho4 constitute the game o%s"ien"e.

•


14/19

#ompetition and sele"tion

• =t6s tempting to dra4 an analogy bet4een 4hat opper des"ribesand e$ol!tion.

• alsi@"ation o% a theory 4o!ld be something li-e etin"tion.• #ontin!ed 4or- on an !n%alsi@ed theory 4o!ld be li-e the

"ontin!ation o% a spe"ies o$er time.• B!t note ho4 m!"h ri"her the e$ol!tionary pi"t!re is.• '$ol!tion is (as Aar4in de@ned it) descent 'ith odication.• othing in s!"h a $ie4 r!les o!t modi@"ation o% a theory in the

"o!rse o% trying to ma-e it @t the phenomena.• 'tin"tion "an still o""!r, i% no s!itable modi@"ations arise.• =n s"ien"e, modi@"ations that are p!rely ad ho" rarely s!""eed o$er

the longer term.•

!rther, in e$ol!tion many spe"ies that are not optimally adapted totheir en$ironment "an still persist %or some time.• =n parti"!lar, in the absen"e o% superior copetition 4or- may 4ell

"ontin!e on a theory e$en a%ter s"ientists are "on$in"ed that it is4rong8 a%ter all, the 4or- may 4ell %o"!s %!rther in$estigation oniss!es that 4ill help 4ith the de$elopment o% a ne4 theory.


15/19

rom logi" to psy"hology

• or opper, as %or the positi$ists, the aim o% philosophy o% s"ien"e 4as to lay o!tho4 s"ien"e sho!ld be done, and the "riteria %or this notion 4o!ld be%!ndamentally logi"al8 they 4o!ld t!rn on the logi"al relations bet4een as"ienti@" theory and obser$ations.

• B!t the A!hemK!ine problem led him to t!rn this logi"al line into apsy"hologi"al one: the s"ientist is someone 4ho 4o!ld not a$oid %alsi@"ation byblaming 2a!iliaries68 she 4o!ld pla"e her theory in the harshest en$ironmentpossible, and blame her theory i% the res!lts don6t @t. ere the psy"hology o%de"ision ma-ing repla"es the logi" o% theory and e$iden"eG

• &his means that s"ientist a"t!ally ris-s reDe"ting a tr!e theory (i% she retains a%alse a!iliary or e$en a %alse obser$ations and "onseE!ently regards the theoryas %alsi@ed).

• &he last shred o% logi"al progress (a steady a""!m!lation o% %alsi@ed theories) inopper6s game o% s"ien"e is lost here.

• !rther, the demar"ation opper had so!ght be"omes problemati" too. opper"an still dra4 a logi"al line, i% he "an spe"i%y 4hi"h theories 4o!ld be %alsi@ed bysome possible obser$ations8 b!t the !sers o% these theories "o!ld still de%endthem, in prin"iple, by shi%ting the blame else4here.

• Mod%rey0Smith also emphasiIes a problem %or probabalisti" theories (s!"h as"lassi"al thermodynami"s)8 i% all they tell !s is that "ertain obser$ations arevery ipro%a%e, then stri"tly spea-ing they aren6t really %alsi@ableN gain, thepsy"hology rather than the logi" o% s"ien"e be"omes "entral here.


16/19

&he problem o% ind!"tion"omes home to roost

• Mod%rey Smith s!ggests a E!estion opper "annot "redibly ans4er:• S!ppose 4e are b!ilding a bridge, and 4e ha$e t4o theories 4e might

employ to g!ide o!r 4or-.• >ne theory has been tested in many "ases, and passed all the tests.• nother has yet to be tested, b!t (tri$ially) has passed e$ery test 4e6$e

e$er p!t it to.•


17/19

&a-ing ris-s

• '$en 4ith all these reser$ations, Mod%rey0Smith thin-sopper 4as onto something 4orth4hile:

• &he idea that s"ienti@" theories m!st ta-e ris-s8 theym!st ha$e eno!gh 2empiri"al "ontent6 (e$en asE!ali@ed by A!hem and !ine) that they really "o!ld

be sho4n (or at least D!sti@ably a""epted to ha$e beensho4n) %alse.

• B!t this %o"!ses more attention on ho4 a theory isdeployed, and ho4 its !sers respond to diF"!lties,than on the 2logi"6 o% the theory itsel%. r 4e "anpro"eed non0s"ienti@"ally, by isolating and shelteringthe theory %rom any and all empiri"al threats. &hese"hoi"es are e$en open to re!dians and /arists.


18/19

re"ambrian +abbits

• standard one0line ans4er to the E!estion,4hat 4o!ld re%!te e$ol!tion.

• >% "o!rse it 4o!ld ta-e $ery "are%!l 4or- toestablish s!"h an asto!nding res!lt.

•B!t there are many other tests e$ol!tion haspassed and "ontin!es to pass (the in0prin"ipleindependent tree0str!"t!res o% taonomy,bio"hemistry, de$elopment and the %ossil re"ord"ontin!e to mat"h !p, %or eample). pplying

ne4 tests to these trees has led to many ne4res!lts and m!"h re@nement o% o!r $ie4s on the"o!rse o% e$ol!tionJb!t they ha$e al4ays @t4ithin the narro4 range o% res!lts a""eptable %ore$ol!tion.


19/19

Sir ?arl: 190199*

philosophy of k. popper

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