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IntroductionIn 1917, the American Hebern invented the HCM (Hebern Cipher machine) whose encrypting element is a rotor. The page bible gives some problems about this machine. This page, gives solutions of these problems. Part A: The Hebern machine use only one rotor (no other permutations)Chapter 1: We know everything (rotor wiring)1. Decipher the following messages. You can use the tables given.a) First message Key: Rotor FTQ, Extern key: Z, cipher mode
Cryptogram:
BTHJG DVXLH PWQ
Plain:
TO BE OR NOT TO BE
b) Second messageKey: Rotor OBC, External Key: Z, decipher mode:
Crytptogram:
FTUOE DDJQS TOLIY GOAUC PWJOD XIYX
Plain text:
A LIVE DOG IS BETTER THAN A DEAD LION
2. Same, but we use mathematical formulasa) First messageKey : Rotor FTQ, External key: Z, cipher mode, Cryptogram:
cryptogram:
JZJFR
ALPHABET:
A:0, B:1, C:2, D:3, E:4, F:5, G:6, H:7, I:8, J:9, K:10, L:11,
M:12, N:13, O:14, P:15, Q:16, R:17, S:18, T:19, U:20, V:21,
W:22, X:23, Y:24, Z:25
PI:
F, 1 :T, 2 :Q, 3 :J, 4 :V, 5 :A, 6 :X, 7 :M, 8 :W, 9 :D,
10 :S, 11 :N, 12 :H, 13 :L, 14 :R, 15 :U, 16 :C, 17 :O,
18 :K, 19 :B, 20 :P, 21 :E, 22 :I, 23 !G , 24 :Z, 25 :Y
y = PI[x+i] -i (or PI[x-i] + i)
y0 = PI[J + 0 ] - 0 = PI[ 9 ] = D
y1 = PI[Z+1 ] - 1 = PI[ 25 + 1 ] - 1 = PI[ 0 ] - 1 = F 1 = E
y2 = PI[J + 2 ] - 2 = PI[ 9 + 2 ] - 2 = PI[ 11 ] - 2 = N 2
= 13 2 = 11 = L
y3 = PI[F +3 ] -3 = PI[ 5+3] 3 = PI[ 8 ] -3 = W 3 = 22 -3
= 19 = T
y4 = PI[R + 4 ] - 4 = PI[ 17 + 4 ] - 4 = PΟ[ 21 ] - 4 = E 4
= 4 4 = 0 = A
Then, plain text = DELTA
b) Second messageKey : Rotor OBC, External key: G, cipher mode
Cryptogram:
XAXNGG
ALPHABET:
A:0, B:1, C:2, D:3, E:4, F:5, G:6, H:7, I:8, J:9, K:10,
L:11, M:12, N:13, O:14, P:15, Q:16, R:17, S:18, T:19, U:20,
V:21, W:22, X:23, Y:24, Z:25
PI_inverse:
[0 :5, 1 :1, 2 :2, 3 :7, 4 :18, 5 :23, 6 :21, 7 :15, 8 :8,
9 :4, 10 : 22, 11 :3, 12 :20, 13 :16, 14 :0, 15 :25, 16 :24,
17 :14, 18 :12, 19 :6, 20 :9, 21 :19, 22 :13, 23 :11, 24 :17,
25 :10]
y = PI_inv[x + i ] - i
y0 = PI_inv[ X + H ] - H = PI_inv[ 23 + 7 ] - 7
= PI_inv[ 4 ] - 7 = 18 7 = 11 = L
y1 = PI_inv[ A + (H + 1) ] - (H+1) = PI_inv[ 8 ] - 8
= 8 8 = 0 = A
y2 = PI_inv[ X + (H + 2) ] - (H+2) = PI_inv[ 23 + 7 + 2 ] - 9
= PI_inv[ 6] 9 = 21 9 = M
Plain Text: LAMBDA
3. Decipher the following messageKey : Rotor OBC, External Key: B, ciphermode,
Cryptogram:
XWFJT GUSBR BGUEV POXDZ MIXEE TEHAT DXABM ZCWKT PPHKG QLIJG
WZXRT OGUHT OMOTF VXLTT WWAAG PXZYM OLQIT WFYJT FQSES GCLNC
WGOBR IMLLL UDIEH BPEB
Plain text:
I HAVE JUST RETURNED FROM A VISIT TO MY LANDLORD , THE
SOLITARY NEIGHBOUR THAT I SHALL BE TROUBLED WITH. THIS IS
CERTAINLY A BEAUTIFUL COUNTRY.
Note : the cryptogram is long, I suggest you write on a software to decipher it.
4. Trigonometric directionKey : rotor : FTQ, Extern Key : D, cipher mode, Trigonometric direction
Cryptogram:
OGUYB
ALPHABET:
A:0, B:1, C:2, D:3, E:4, F:5, G:6, H:7, I:8, J:9, K:10,
L:11, M:12, N:13, O:14, P:15, Q:16, R:17, S:18, T:19, U:20,
V:21, W:22, X:23, Y:24, Z:25
PI = PI_inv (PI inverse):
0 :F, 1 :T, 2 :Q, 3 :J, 4 :V, 5 :A, 6 :X, 7 :M, 8 :W, 9 :D,
10 :S, 11 :N, 12 :H, 13 :L, 14 :R, 15 :U, 16 :C, 17 :O,
18 :K, 19 :B, 20 :P, 21 :E, 22 :I, 23 :G , 24 :Z, 25 :Y
x = PI_inv[y - i] + i
In trigonometric mode, the key decreases, in fact, the rim
of the rotor: A (0), Z (25), Y (24), ..., B (1)
But the index i increases: 0, 2, 3, ... 25
Dont forget : the rotor advance before ciphering,
then the index of D is 23 and the effective key is 23+1=24.
y0 = PI[ 'O' - 24 ] + 24 = PI[ 16 ] + 24 = 'C' + 24 = 2 + 24 = 0 = 'A'
y1 = PI[ 'G' - 25 ] + 25 = PI[ 7 ] + 25 = 'M' + 25 = 12+25 =11 = 'L'
y2 = PI[ 'U' - 0 ] + 0 = PI[ 20 ] = 'P'
y3 = PI[ 'Y' - 1 ] + 1 = PI[24-1] + 1 = PI[23] +1 = 'G' + 1 = 'H'
y4 = PI[ 'B' - 2 ] + 2 = PI[25] + 2 = 'Y' + 2 = 'A'
Plain Text: ALPHA
Chapter 2: We know the cryptogram and the plain text
Cryptogram:
CPCKA TIEHT EIDDZ HVZDC ZRQXS MZIMA KEINJ UQAMO GDXIY VNOZU
XLZLY PGSJO NCXQQ PCQXE QWOKD RFKKD YKGCF TVMAJ UUMBD NWUKE
GJMLP TUKUK KBHBT YLDFC SVSAL FIGRK NWIFF JCKWG ENDCV CSIDU
MQDXO CKYGL LDKBN CAJRP ZJXNW FTJYU RAEWS SMHUH HVXWN DJFWN
MEPFG INLLT IK
Plain text (From Galileo Galilei) :
AFTER SEVERAL ATTEMPTS CONSIDERING NEITHER LABOR NOR EXPENSE
I MANAGED TO CONSTRUCT AN INSTRUMENT WHICH ENLARGES OBJECTS
MORE THAN EIGHT TIMES Z DOT Z TO THE PROFOUND AMAZEMENT OF
HIS LORDSHIP AND THE ENTIRE SENATE OF VENICE I DEMONSTRATED
MY TELESCOPE
We create the encryption table: (plain: column head, key: row head
and intersection: cipher letter)- key A; cipher: C, plain: A - key B; cipher: P, plain: F - key C; cipher: C, plain: T ...
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
A- C L Z N P K E
B- Y W P L T I D
C- M Y S I U G C
D- P K L S A F
E- M K L G F A U
F- S H J K E D T C
G- K I J U C F
H- H O T N B K E
I- N H V W J
J- M G U B V T C
K- E Q T A X
L- Q J Y I N W A
M- D R M U Q N L
N- O U P D C
O- M G V F J C Z
P- F H J C D B Q
Q- S D V X W
R- N I Z V E
S- Q M Y W D S
T- A F E U V C W
U- O K Z N M T L P
V- J Q E K R F O
W- G D Q Z Y I
X- J U I R X G
Y- N S O X R F M
Z- M A C L K
We complete the diagonals to find the rotor wiring (1st line).
Since the Lampboard and Keyboard permutations are equal to the
identity permutation, the diagonals correspond to the normal
alphabet (ABCDEF...XYZ).
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
A- C R L S Z X Q N M O V P B A U D K J W I E T Y H G
B- Q R Y W P M L N U O A Z T C I V H D S X G F
C- Q L K M T N Z Y S B I U G C R W F E P
D- P K J L S M Y A F Q V E D O
E- M I K L X G F A P U D C N
F- S H J K W E D O T C B M
G- K I J V U C N B A L F
H- H O U T N B M A Z K E
I- N H T V W L Z Y J
J- M G S U B V K Y X T C
K- E R Q T A J X W
L- Q J Y I N W V A
M- D R M U Q N L
N- O U P D C
O- M G V F J C Z
P- F H J C D B Q
Q- S D V X W
R- N I Z V E
S- Q M Y W D S
T- A F E U V C W
U- O K Z N M T L P
V- J Q E K R F O
W- G D Q Z Y I
X- J U I R X G
Y- N S O X R F M
Z- M A C L K
Wiring:
C R L S Z X Q N F M O V P B A U D K J W I E T Y H G
We can check if the wiring is good by deciphering the cryptogram
via my Hebern machine simulator or by displaying the complete
encryption table with my program hebern1_table.py.
C:\H1_TOOLS> python hebern1_table.py -R =CRLSZXQFNMOVPBAUDKJWIETYHG
PI: [2, 17, 11, 18, 25, 23, 16, 5, 13, 12, 14, 21, 15, 1, 0, 20,
3, 10, 9, 22, 8, 4, 19, 24, 7, 6]
PI_inv: [14, 13, 0, 16, 21, 7, 25, 24, 20, 18, 17, 2, 9, 8, 10,
12, 6, 1, 3, 22, 15, 11, 19, 5, 23, 4]
Rotor in clockwise direction, Coord of a ciphered letter:
Abscissa: Plain letter, ordinate: Position of rotor (key)
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
A C R L S Z X Q F N M O V P B A U D K J W I E T Y H G
B Q K R Y W P E M L N U O A Z T C J I V H D S X G F B
C J Q X V O D L K M T N Z Y S B I H U G C R W F E A P
D P W U N C K J L S M Y X R A H G T F B Q V E D Z O I
E V T M B J I K R L X W Q Z G F S E A P U D C Y N H O
F S L A I H J Q K W V P Y F E R D Z O T C B X M G N U
G K Z H G I P J V U O X E D Q C Y N S B A W L F M T R
H Y G F H O I U T N W D C P B X M R A Z V K E L S Q J
I F E G N H T S M V C B O A W L Q Z Y U J D K R P I X
J D F M G S R L U B A N Z V K P Y X T I C J Q O H W E
K E L F R Q K T A Z M Y U J O X W S H B I P N G V D C
L K E Q P J S Z Y L X T I N W V R G A H O M F U C B D
M D P O I R Y X K W S H M V U Q F Z G N L E T B A C J
N O N H Q X W J V R G L U T P E Y F M K D S A Z B I C
O M G P W V I U Q F K T S O D X E L J C R Z Y A H B N
P F O V U H T P E J S R N C W D K I B Q Y X Z G A M L
Q N U T G S O D I R Q M B V C J H A P X W Y F Z L K E
R T S F R N C H Q P L A U B I G Z O W V X E Y K J D M
S R E Q M B G P O K Z T A H F Y N V U W D X J I C L S
T D P L A F O N J Y S Z G E X M U T V C W I H B K R Q
U O K Z E N M I X R Y F D W L T S U B V H G A J Q P C
V J Y D M L H W Q X E C V K S R T A U G F Z I P O B N
W X C L K G V P W D B U J R Q S Z T F E Y H O N A M I
X B K J F U O V C A T I Q P R Y S E D X G N M Z L H W
Y J I E T N U B Z S H P O Q X R D C W F M L Y K G V A
Z H D S M T A Y R G O N P W Q C B V E L K X J F U Z I
C:\H1_TOOLS> python hebern1_tui.py -R ^
=CRLSZXQNFMOVPBAUDKJWIETYHG -d ^
< gallilee.cry
AFTERSEVERALATTEMPTSCONSIDERINGNEITHERLABORNOREXPENSEIMANAGED
TOCONSTRUCTANINSTRUMENTWHICHENLARGESOBJECTSMORETHANEIGHTTIMES
ZDOTZTOTHEPROFOUNDAMAZEMENTOFHISLORDSHIPANDTHEENTIRESENATEOF
VENICEIDEMONSTRATEDMYTELESCOPE
Chapter 3: We only have the cryptogram
Cryptogram:
EHDXF GCFOU VIIIP GICBI HYBNN DOJDE YBZJZ ITLCA DYUNC NCEUH
ADOQL EAJBU ZOFXG XOGYK UYUWV TXAPK VWBFG OONOM IHSPY ZPQJI
GNHHB DEKHF ZVBIP JIXSA PHEXJ NEBAB SWEIL KETOP JQYAS GBCOG
UYGDF GBDEZ JSVMD UDKIP LGYCC RKJLZ TYBTW TLRCX QPYXY EMABH
CIMYV TWUUW WBYHJ NBOFM ZHAEY EENAL WYMJO SVCSW HBBLQ SJTZM
CHOTE SXNHP CFZLD HUAJY UMVTO NVCEN DEZNA GJMFT BWGXB EILYA
LFNWV OJGED TKSYE KSSGD WYPRI BTHCK PIMJY FAMHA EDLEU FBOEF
WTMKY QIJVY ZZZYV MVWJG MNNOC NVHXA UHEYP CEWAD EWEKF XAMSQ
HFYSY IUOBI ZDBSN AZQFT MOXOZ UDKGT OUUHK NNNWT SPCMF MOGZD
JCYYZ XAKJW NDKNR OMPCK RNRWX GHCSM XQWGF TBIVQ EPFDS ALXOY
SBBNC NZXOJ DWVCE NDPLR VJLNB LRDHG PRZXO ZVLOE DNDUN NJJDE
AZCMJ WTSXH RWCJU QXREL IACDW AAOQK WYYTF QUJVJ OHIFE EAMIH
FXYHZ THLYA ZFAHR MTLKN DUNPC GRWLR UIQWH KGTZM XWQWP NAYNC
JKLNY XXHFA PRXTA HNCCX UYZWA NXGLC GOASW FTAWU KKOVS TTRZE
AAXDS ZYYRJ MOOHP KACVA EDEZV UXAXG DEAZC MJWTS GWRKD UIYME
SSXBD STKCS UASOT MKKGZ YONVW EMINA ZQFWB FITQH PQCSZ MKNCX
DEHNS DOJIL IOZGH EYSYE NPZWO HJNWP FBJUI LRKJH JCYNY UUJVC
KHEWE LLCCQ ZPFYU WLOPD ZSDQV BVYVS ZUCYZ JVKVZ BNG
Rotor:
URYZSKGOETAQJXIVLFCBHNWPDM
Plain text:
IN PHILISOPHY OCKAM S RAZOR IS THE PROBLEM SOLVING
PRINCIPLE THAT RECOMMENDS SEARCHING FOR EXPLANATIONS
CONSTRUCTED WITH THE SMALLEST POSSIBLE SET OF ELEMENTS
Z DOT Z IT IS ALSO KNOWN AS THE PRINCIPLE OF PARSIMONY
Z DOT Z ATTRIBUTED TO WILLIAM OF OCKAM A FOURTEEN
CENTURY ENGLISH PHILOSOPHER AND THEOLOGIAN IT IS
FREQUENTLY CITED AS ENTITIES MUST NOT BE MULTIPLIED
BEYOND NECESSITY ALTHOUGH OCCAM NEVER USED THESE
EXACT WORDS Z DOT Z POPULARLY THE PRINCIPLE IS
SOMETIMES INACCURATELY PARAPHRASED AS THE SIMPLEST
EXPLANATION IS USUALLY THE BEST ONE Z DOT Z THIS
PHILOSOPHICAL RAZOR ADVOCATES THAT WHEN PRESENTED WITH
COMPETING HYPOTHESES ABOUT THE SAME PREDICTION AND
BOTH THEORIES HAVE EQUAL EXPLANATORY POWER ON SHOULD
PREFER THE HYPOTHESIS THAT REQUIRES THE FEWEST
ASSUMPTIONS AND THAT THIS IS NOT MEANT TO BE A WAY OF
CHOOSING BETWEEN HYPOTHESES THAT MAKE DIFFERENT
PREDICTIONS Z DOT Z SIMILARLY IN SCIENCE OCKAM S RAZOR
IS USED AS AN ABDUCTIVE HEURISTIC IN THE DEVELOPMENT
OF THEORETICAL MODELS RATHER THAN AS A RIGOROUS
ARBITER BETWEEN CANDIDATE MODELS Z DOT Z
Part B: The wiring of the rotor and keyboard are unknownChapter 1: We know the cryptogram and the plain textPlain text (John Locke): Slavery is so vile and miserable an Estate of Man and so directly opposite to the generous Temper and Courage of our Nation that it is hardly to be conceived that an Englishman much less a Gentleman should plead for it z dot z And truly I should have taken Sir Robert Filmer quote s Patriarcha as any other Treatise which would persuade all men that they are slave, and ought to be soCryptogram:
ZOIFN OUUVE RKQPY DXLCZ UKGLA NQESV YGKBO BXTRE IOQUR YGLOU
YNRLX SETEB OLRUB UPWXR HKQZH EXGQM IUHZO LEPSI JCSTU FMFGB
LQWVA HCRYL KAMQC UJBYV IFDBG XOZYY XSIUN FTDRE ZTREX TLNVB
UZTOB QAOAO VFLVX KLZKP YDQGR CGOJZ VTVES JIOQD WMMSJ YKBDC
LBXQP ENCPM UMOEY BLMLT SHNTI PWPVQ HBOVD VZYVT KSWBN SSHLQ
ZCKZU KVROE FRJGQ KWGEE UYPUI CTXWH XUTQY YQIIP NTZZC JHRPD
BYDPK KBKBD
We fill in the table as before (Part A, chapter 2)
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
A- X Q F P D Z A R V
B- E V H O L M S R I
C- I A Z S J X U C
D- Y J V R O U M S P G F
E- V O H N Q E Y I
F- Z K E L F O T G
G- K T E Z O W Y L Q U
H- Z G V U D S A B L
I- M O L R X E V C W
J- P J M Q B E L K
K- H X S Z L R M N U C
L- Y Z I S T R U K
M- R P S B Q J K
N- B U C P E D H Y
O- I Y P K X S N L B
P- D V B W Y C O Q T
Q- L Q Z D T X I U
R- C L R G N X F U P
S- M D W V C R H K L
T- Y B Z H K C P F
U- B G V U X Q
V- Q K U B L Z O X
W- T O P L G B H V J
X- L U Z E O R D B Q
Y- A B W O X N V Y
Z- V E Y N Q G C T
After anagramming:
A H P X S Z E M U F Y B R C W Q T D J O V L I N G K
------------------------------------------------------------------------------
X F Z V Q R D A P
E I M V R S L O H
I Z X A U C J S
Y S V O G P J M F R U
V Y N O I H E Q
L T E O Z G K F
K W L Q U Y O Z E T
Z V G L A B D U S
V O L W E M X C R
P E J K L B Q M
H Z M U X C N R L S
Y S I T U Z K R
R B K S P J Q
U Y C B H D P E
I Y X B N L S K P
D W T Q V B C O Y
D Z U L Q I T X
C N U R X G P L F
M W C H D K R L V
P B C F Y K Z H
V U Q B X G
Q U Z K L O B X
T B J O G V H L P
L R E B U Q Z D O
W B X A Y V O N
V Y G C E T N Q
We fill in the diagonals:
A H P X S Z E M U F Y B R C W Q T D J O V L I N G K
------------------------------------------------------------------------------
X F K B Z V Q G C Y R J D N W S A T E H M L P I O U
E J A Y F B X I M V R S D G L K O H N T
I Z X E A W U C F K J M S
Y S D Z V O G P E J M F L R U
V C Y N O D I H E K Q
L B X T E O Z C H G K J P F
K A W L Q U Y B G I O Z E T
Z V G L A F B H N D U S
V O L W E G M X C R
P E J K F L B Q M
H Z M U X C E N R L S
Y S I T D U Z K R
R B K S C P J Q
U Y C B H D P E
I Y X B N L S K P
D W T Q V B C O Y
D Z U L Q I T X
C N U R X G P L F
M W C H D K R L V
P B C F Y K Z H
V U Q B X G
Q U Z K L O B X
T B J O G V H L P
L R E B U Q Z D O
W B X A Y V O N
V Y G C E T N Q
Rotor (first line):
X F K B Z V Q G C Y R J D N W S A T E H M L P I O UKeyboard inverse (head of the columns): A H P X S Z E M U F Y B R C W Q T D J O V L I N G KKeyboard: A L N R G J Y B W S Z V H X T C P M E Q I U O D K FUsing my simulator I can check the results:
C:\H1_TOOLS> python hebern1_tui.py -K =ALNRGJYBWSZVHXTCPMEQIUODKF ^
-R =XFKBZVQGCYRJDNWSATEHMLPIOU -d < locke.cry
SLAVERYISSOVILEANDMISERABLEANESTATEOFMANANDSODIRECTLYOPPOSITETOTHE
GENEROUSTEMPERANDCOURAGEOFOURNATIONTHATITISHARDLYTOBECONCEIVEDTHAT
ANENGLISHMANMUCHLESSAGENTLEMANSHOULDPLEADFORITZDOTZANDTRULYISHOULD
HAVETAKENSIRROBERTFILMERQUOTESPATRIARCHAASANYOTHERTREATISEWHICHWOU
LDPERSUADEALLMENTHATTHEYARESLAVEANDOUGHTTOBESO
Chapter 2: We only have the cryptogramCryptogram:ZAOCF XWHKT JFWHR WCSBY MSBUV YXEBN QFGYX SBCWA EXBWZ CFPOU SULCY BAFVQ HAKKW NXCFY KEMPG RVEHM SMFMS VKZSD KCKNI KFBZA TTWHD KIPSJ AYTVM ISBDT BURHP UBRUM DYZQX MZLNJ IQKWI XXHXJ CFRGV NQMRR LHCVQ NAOZB CXDHZ LOPDG BHZYR BMRZL CUIRW XVJRP TUKPY WAEAP BAKXK ESFXN ENECR DRKTL MWIHD KSMFJ RUYCK KFCTZ CQRLP BMJAV CPKWB LWYXZ RZKAA TSUOG VOCUV YTUZM QRYZB UYZKA ACNWG OJYNG TSHDO WXLWF GMRLT BCXZX THJSE MLNBR NPCPM FQTRQ KCKZV NWYPS PUSEG PDBZA MHNPY TIVTX RBTUK UCNBN FSAXB FFFUA KKWNX CFYKE BFASA WMYKB MIOOE XRTYC KWWKG OPWMW QNXMR RLHLY UPYTI VKZNU RUKPY WZMMZ KKVDE UCJYZ KVATR RZLBO CGTBB USKAH RWQTI GKVEZ XKRUN RUEBM EUKKM WRUQV TOKUU RFXPY BWNTI GKMAN HERYX PXIIR EWWHX HDSMA CHECD NJMCP HJUFN PJTVL DKGAM OKMYU XKXPO JHSBT ZURMU WPANR ETILH PSXXP OHCRZ XDBCX RURON UVOZG YUXKX PMZLY ZZNDT ACHXC UPNPT PASBN QFGUQ PXQAD XAHJG LAYBL TELZP KVXZB STSLJ LRGIC PYKSD JHVAP AJZUM NCJIW IBKZV VOMOE BFLNY CDQPU BLQTC CBDHC NYIHV WNKAN RYDBE MEYUV TOQDN XSPHL ECMWZ CHSSQ PHRBU SUSMJ AGHQH CMVRX VHHSS WKLWU YUXNL WQWYG PWIAM GHKDY NPFYK EWDJT JRVBI WTSNR CRVHM CPKQH EQQFB ZNDKQ CPZXW FYPWZ APTNJ MZEWD SDSBU CVUOR CFNKA WTACK KPOBS AKKWN XCFYK EJUEG HKDYA FBERJ QXSDS RWUDM BLPFW IAEFU NRCMY FNSYR WXVJY QEBBA DUDHG BRAQH BJKUB RWBCX WKTEP EQLZG ZGRAS RCVYE XYJYU XVWKM OEBFZ EGFZB QAEVK ZJFNX JWHET DCKRQ SHECB TQUZU HJBIK CTAIE KEVEV TDWHD BPOPM FQTLO WIRXV AJOPS DMIWA RXBBI RLISU OQTZG IKDUV KNGTE LUAPU RLHID KEIYV JBUEL MPCXV HHSSW KLWFN JUFDV IOICP UVYQM LGAVR QGURI LCMMW HUUSK EJVVB TTETZ DGBER XXJSC JASIH EJQJR ELHYD ZYLAL EYTQY KYBRR FPZOM RJMBO ARUNS RWFST MTFXT URHXF JEVJQ MBZZW AHLYU VTOKU KQCPZ CCYRW ABSYI QPRZA KJLQI NECRDPlain text: POPPER COINED THE TERM CRITICAL RATIONALISM TO DESCRIBE HIS PHILOSOPHY Z DOT Z POPPER REJECTED THE EMPIRICIST VIEW FOLLOWING FROM KANT THAT BASIC STATEMENTS ARE INFALLIBLE RATHER ACCORDING TO POPPER THEY ARE DESCRIPTIONS IN RELATION TO A THEORETICAL FRAMEWORK Z DOT Z CONCERNING THE METHOD OF SCIENCE THE TERM CRITICAL RATIONALISM INDICATES HIS REJECTION OF CLASSICAL EMPIRICISM AND THE CLASSICAL OBSERVATIONALIST INDUCTIVIST ACCOUNT OF SCIENCE THAT HAD GROWN OUT OF IT Z DOT Z POPPER ARGUED STRONGLY AGAINST THE LATTER HOLDING THAT SCIENTIFIC THEORIES ARE ABSTRACT IN NATURE AND CAN BE TESTED ONLY INDIRECTLY BY REFERENCE TO THEIR IMPLICATIONS Z DOT Z HE ALSO HELD THAT SCIENTIFIC THEORY AND HUMAN KNOWLEDGE GENERALLY IS IRREDUCIBLY CONJECTURAL OR HYPOTHETICAL AND IS GENERATED BY THE CREATIVE IMAGINATION TO SOLVE PROBLEMS THAT HAVE ARISEN IN SPECIFIC HISTORICOCULTURAL SETTINGS Z DOT Z LOGICALLY NO NUMBER OF POSITIVE OUTCOMES AT THE LEVEL OF EXPERIMENTAL TESTING CAN CONFIRM A SCIENTIFIC THEORY BUT A SINGLE COUNTEREXAMPLE IS LOGICALLY DECISIVE IT SHOWS THE THEORY FROM WHICH THE IMPLICATION IS DERIVED TO BE FALSE Z DOT Z POPPERS ACCOUNT OF THE LOGICAL ASYMMETRY BETWEEN VERIFICATION AND FALSIFIABILITY LIES AT THE HEART OF HIS PHILOSOPHY OF SCIENCE Z DOT Z IT ALSO INSPIRED HIM TO TAKE FALSIFIABILITY AS HIS CRITERION OF DEMARCATION BETWEEN WHAT IS AND IS NOT GENUINELY SCIENTIFIC A THEORY SHOULD BE CONSIDERED SCIENTIFIC IF AND ONLY IF IT IS FALSIFIABLE Z DOT Z THIS LED HIM TO ATTACK THE CLAIMS OF BOTH PSYCHOANALYSIS AND CONTEMPORARY MARXISM TO SCIENTIFIC STATUS ON THE BASIS THAT THEIR THEORIES ARE NOT FALSIFIABLE Z DOT Z References
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