25 8 TURIN G

o f th e machine . Th e mechani c wh o ha s constructe d th e machine , however ,

i s permitte d t o kee p th e machin e i n runnin g order , an d i f h e suspect s tha t

th e machin e ha s bee n operatin g incorrectl y ma y pu t i t bac k t o on e o f it s

previou s position s an d as k th e schoolmaste r t o repea t hi s lesson s fro m tha t

poin t on , bu t h e ma y no t tak e an y par t i n th e teaching . Sinc e thi s proce -

dur e woul d onl y serv e t o tes t th e bon a fides o f th e mechanic , I nee d hardl y

sa y tha t i t woul d no t b e adopte d i n th e experimenta l stages . A s I se e it ,

thi s educatio n proces s woul d i n practic e b e a n essentia l t o th e productio n

o f a reasonabl y intelligen t machin e withi n a reasonabl y shor t spac e o f time .

Th e huma n analog y alon e suggest s this .

I ma y no w giv e som e indicatio n o f th e wa y i n whic h suc h a machin e

migh t b e expecte d t o function . Th e machin e woul d incorporat e a memory .

Thi s doe s no t nee d ver y muc h explanation . I t woul d simpl y b e a lis t o f al l

th e statement s tha t ha d bee n mad e t o i t o r b y it , an d al l th e move s i t ha d

mad e an d th e card s i t ha d playe d i n it s games . Thes e woul d b e liste d i n

chronologica l order . Beside s thi s straightforwar d memor y ther e woul d b e a

numbe r o f 'indexe s o f experiences' . T o explai n thi s ide a I wil l sugges t th e

for m whic h on e suc h inde x migh t possibl y take . I t migh t b e a n alphabetica l

inde x o f th e word s tha t ha d bee n use d givin g th e 'times ' a t whic h the y ha d

bee n used , s o tha t the y coul d b e looke d u p i n th e memory . Anothe r suc h

inde x migh t contai n pattern s o f me n o r part s o f a G O boar d tha t ha d

occurred . A t comparativel y lat e stage s o f educatio n th e memor y migh t b e

extende d t o includ e importan t part s o f th e configuratio n o f th e machin e

a t eac h moment , o r i n othe r word s i t woul d begi n t o remembe r wha t it s

thought s ha d been . Thi s woul d giv e ris e t o fruitfu l ne w form s o f indexing .

Ne w form s o f inde x migh t b e introduce d o n accoun t o f specia l feature s

observe d i n th e indexe s alread y used . Th e indexe s woul d b e use d i n thi s sor t

o f

way .

Wheneve r a choic e ha s t o b e mad e a s t o wha t t o d o nex t feature s o f

th e presen t situatio n ar e looke d u p i n th e indexe s available , an d th e previou s

choic e i n th e simila r situations , an d th e outcome , goo d o r bad , i s discovered .

Th e ne w choic e i s mad e accordingly . Thi s raise s a numbe r o f problems . I f

som e o f th e indication s ar e favourabl e an d som e ar e unfavourabl e wha t

i s on e t o do ? Th e answe r t o thi s wil l probabl y diffe r fro m machin e t o

machin e an d wil l als o var y wit h it s degre e o f education . A t first probabl y

som e quit e crud e rul e wil l suffice , e.g., t o d o whicheve r ha s th e greates t

numbe r o f vote s i n it s favour . A t a ver y lat e stag e o f educatio n th e whol e

questio n o f procedur e i n suc h case s wil l probabl y hav e bee n investigate d b y

th e machin e

itself ,

b y mean s o f som e kin d o f index , an d thi s ma y resul t i n

som e highl y sophisticated , and , on e hopes , highl y satisfactory , for m o f rule .

I t seem s probabl e howeve r tha t th e comparativel y crud e form s o f rul e wil l

themselve s b e reasonabl y satisfactory , s o tha t progres s ca n o n th e whol e

b e mad e i n spit e o f th e crudenes s o f th e choic e rules . Thi s seem s t o b e

verifie d b y th e fac t tha t Engineerin g problem s ar e sometime s solve d b y th e