WHAT IS LIFE? - Strange beautiful

1 WHATISLIFE?withMINDANDMATTER&AUTOBIOGRAP HICALSKETCHESThis page intentionally left blankWHATISLIFE?ThePhysicalAspectoftheLi vingCellwithMINDANDMATTER&AUTOBIOGRAPHIC ALSKETCHESERWINSCHRODINGERUCAMBRIDGE.:J~ UNIVERSITYPRESSWhat is LIFE? andMind and matter Cambridge University Press 1967 what IS LIFE? First published 1944 Reprinted 1945, 1948, 1951, 1955, 1962 MIND AND MATTERF irst published 1958 Reprinted 1959 Combined reprint 1967 Canto edition with Autobiographical Sketches and Cambridge University Press 1992 First printed 1992 printed and bound by CPI roup UK Ltd, Croydon, cr yy~Cambridge University PressPublished in the United States of America by Cambridge University Press, New to what is life ?

2 By Roger PenroseCambridge University Press has no responsibility for the persistence or accuracy of URLs for external or third-party internet websites referred to in this publication, and does not guarantee that any content on such websites is, or will remain, accurate or - - - PaperbackThe Edinburgh Building, Cambridge cb2 8ru, UKisbn 978 Cambridge, New York, Melbourne, Madrid, Cape Town, Singapore, Sao Paulo, Delhi, Information on this title: 81107604667C AM B RIDGE U N IV E R S IT Y PR ES S201th printingMex ico City1 107 60466 70 4G()G()314 Contents what IS life ? Preface THE CLASSICAL PHYSICIST'S APPROACH TO THE SUBJECT page 1 3 The general character and the purpose of the investigation -Statistical physics.

3 The fundamental difference in structure -The naive physicist's approach to the subject - Why are the atoms so small? -The working of an organism requires exact physical laws-Physical laws rest on atomic statistics and are therefore only approximate - Their precision is based on the large number of atoms intervening. 1st example (paramagnet ism) - znd example (Brownian movement, diffusion) -3rd example (limits of accuracy of measuring)-The V n rule 2 THE HEREDITARY MECHANISM '9 The classical physicist's expectation, far from being trivial, is wrong-The hereditary code-script (chromosomes)- Growth of the body by cell division (mitosis) - In mitosis every chromosome is duplicated-Reductive division (meiosis) and fertilization (syngamy) -Haploid individuals-The outstand ing relevance of the reductive division- Crossing-over.

4 Loca tion of properties-Maximum size of a gene-Small numbers - Permanence IVI Contents 3 MUTATIONS 'Jump-like' mutations- the working-ground of natural selec tion - They breed true, they are perfectly inherited -Localization. Recessivity and Dominance- Introducing some technical language -The harmful effect of close-breeding -General and historical remarks -The necessity of mutation being a rare event- Mutations induced by X-rays-First law. Mutation is a single event-Second law. Localization of the event 4 T H E Q U A N T U M -M E C H A N I C A L E V I D E N C E 46 Permanence unexplainable by classical physics - Explicable by quantum theory - Quantum theory - discrete states -quantum jumps - Molecules -Their stability dependent on temperature - Mathematical interlude - First amendment -Second amendment 5 DELBRUCK'S MODEL DISCUSSED AND TESTED The general picture of the hereditary substance-The unique ness of the picture - Some traditional misconceptions -Different 'states' of matter - The distinction that really matters - The aperiodic solid - The variety of contents compressed in the miniature code.

5 Comparison with facts: degree of stability; discontinuity of mutations - Stability of naturally selected genes -The sometimes lower stability of mutants - Temperature influences unstable genes less than stable ones-How X-rays produce mutation-Their efficiency does not depend on spontaneous mutability - Reversible mutations 6 ORDER, DISORDER AND ENTROPY A remarkable general conclusion from the model - Order based on order - Living matter evades the decay to equilib rium-It feeds on 'negative entropy'- what is entropy?-The 76 6 53 2 Contents VII statistical meaning of entropy- Organization maintained by extracting 'order' from the environment 7 I S L I F E B A S E D 0 N T H E L A W S 0 F P H Y S I C S ?

6 76 New laws to be expected in the organism - Reviewing the biological situation - Summarizing the physical situation -The striking contrast -Two ways of producing orderliness -The new principle is not alien to physics -The motion of a clock - Clockwork after all statistical -Nernst's Theorem -The pendulum clock is virtually at zero temperature -The relation between clockwork and organism E P I L 0 G U E . 0 N D E T E R M I N I S M A N D F R E E W I L L 86 MIND AND matter THE PH Y SIC A L B AS IS 0 F C 0 N SCI 0 USN E S S 93 The problem-A tentative answer-Ethics 2 THE FUTURE OF UNDERSTANDING A biological blind alley?-The apparent gloom of Darwinism - Behaviour influences selection - Feigned Lamarckism -Genetic fixation of habits and skills - Dangers to intellectual evolution 3 THE PRINCIPLE OF OBJECTIVATION IJ7 4 THE ARITHMETICAL PARADOX: THE ONENESS OF MIND 5 SCIENCE AND RELIGION 3 I0I82 I04 IVIII Contents 6 THE MYSTERY 0 F THE SENSUAL QUALITIES I 53 AUTOBIOGRAPHI CA L SKETCHES r65 Translated by Schrodinger's granddaughter Verena WHATISLIFE?

7 THEPHYSICALASPECTOFTHELIVINGCELLB asedonlecturesdeliveredundertheauspiceso ftheDublinInstituteforAdvancedStudiesatT rinityCollege,Dublin,inFebruary1943 TothememoryofMyParentsForewordWhenIwasay oungmathematicsstudentintheearly1950 SIdidnotreadagreatdeal, ,andtherewasanexcitementofdiscovery, ,asInowrealize, , 'scross-disciplinarysweepwasunusualforit stirne-yetitiswrittenwithanendearing,ifp erhapsdisarming,modesty,ata ,manyscientistswhohavemadefunda-mentalco ntributionsinbiology,suchas]. ,haveadmittedtobeingstronglyinfluencedby (althoughnotalwaysincompleteagreementwit h) ,itmakespointsthat,oncetheyaregrasped,ha vearingofalmostself-evidenttruth; ,oreventhatweeatfoodinordertogainenergy?

8 Thisservestoemphasizethecontinuingreleva ncethatSchr(Sdinger'sWhatisLife? !RogerPenrose8 August1991 PrefaceAscientistissupposedtohaveacomple teandthoroughknowledge,atfirsthand,ofsom esubjectsand,therefore, ,ifany, :Wehaveinheritedfromourforefathersthekee nlongingforunified, , ,bothinwidthanddepth, whole;but,ontheotherhand, (lestourtrueaimbelostforever)thanthatsom eofusshouldventuretoembarkonasynthesisof factsandtheories, 'snativespeechisa closelyfittinggarment, (TrinityCollege,Dublin),toDrPadraigBrown e(StPatrick'sCollege,Maynooth)and,lastbu tnotleast, 'original' ,itistobeputatmydoor, , ; ZA'SEthics,PtIV, (Thereisnothingoverwhicha freemanponderslessthandeath;hiswisdomis, tomeditatenotondeathbutonlife.))

9 ,deliveredbyatheoreticalphysicisttoanaud ienceofaboutfourhundredwhichdidnotsubsta ntiallydwindle,thoughwarnedattheoutsetth atthesubject-matterwasa difficultoneandthatthelecturescouldnotbe termedpopular,eventhoughthephysicist'smo stdreadedweapon,mathematicaldeduction, , 'sintentiontomakeclearthefundamentalidea ,whichhoversbetweenbiologyandphysics, ,inspiteofthevarietyoftopicsinvolved, , :Howcantheeventsinspaceandtimewhichtakep lacewithinthespatialboundaryofa livingorganismbeaccountedforbyphysicsand chemistry?34 ERWINSCHRODINGERT hepreliminaryanswerwhichthislittlebookwi llendeav- , ,uptothepresentmoment, ,thankstotheingeniousworkofbiologists,ma inlyofgeneticists,duringthelastthirtyorf ortyyears,enoughisknownabouttheactualmat erialstructureoforganismsandabouttheirfu nctioningtostatethat,andtotellpreciselyw hy,present-dayphysicsandchemistrycouldno tpossiblyaccountforwhathappensinspaceand timewithina 'Thiscontentionmayappeara , 'statisticalstructure' ,letmeanticipatewhatwillbeexplainedinmuc hmoredetaillater,namely,thatthemostessen tialpartofa 'smind,theseareveryinterestingandcomplic atedobjects.

10 ,comparedwiththeaperiodiccrystal, ,sayaRaphaeltapestry,whichshowsnodullrep etition,butanelaborate,coherent, , ,indeed,ininvestigatingmoreandmorecompli catedmolecules,hascomeverymuchnearertoth at'aperiodiccrystal'which,inmyopinion, ,whereasthephysicisthasmadenexttonone.' ,Scientia,XXIV, (1918),10('Lasciencephysico-chimiquedecr it-elled'unefa<;onadequatelesphenomenesb iologiques?');SmithsonianReportfor/929, ('Themysteryoflife').6 ERWINSCHRODINGERTHENAIVEPHYSICIST'SAPPRO ACHTOTHESUBJECTA fterhavingthusindicatedverybrieflythegen eralidea-orrathertheultimatescope-ofouri nvestigation, 'anaivephysicist'sideasaboutorganisms',t hatis,theideaswhichmightariseinthemindof aphysicistwho,afterhavinglearnthisphysic sand,moreespecially,thestatisticalfounda tionofhisscience,beginstothinkaboutorgan ismsandaboutthewaytheybehaveandfunctiona ndwhocomestoaskhimselfconscientiouslywhe therhe,fromwhathehaslearnt,fromthepointo fviewofhiscomparativelysimpleandclearand humblescience, ,toputitmoremodestly, , ,inshort, 'naivephysicist' 'thenaivephysicist'sideas'istostartfromt heodd,almostludicrous.