The Swings of Science: From Complexity to Simplicity and Back

196 Pages·2018·8.329 MB·English

by  Len Pismen

Len Pismen
The Swings of
Science
From Complexity to
Simplicity and Back
The Swings of Science
Len Pismen
The Swings of Science
From Complexity to Simplicity and Back
123
LenPismen
DepartmentofChemicalEngineering
TechnionIsraelInstituteofTechnology
Haifa,Israel
ISBN978-3-319-99776-6 ISBN978-3-319-99777-3 (eBook)
https://doi.org/10.1007/978-3-319-99777-3
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Preface
This book comes from an old man who has wandered among different branches
ofmacroscopicphysics(seehttp://pattern.technion.ac.il/),sometimeslookingwith
envy at the lofty heights above and abysses below where “fundamental” physics
eithersoarsorpenetrates.Mostbooksbeingpublishednowadaysfortheinquisitive
lay public are dedicated to these extremes, which, as we know, come together,as
many extremes do. Although I cannot avoid them in the course of my narrative,
in particular, because they are the parts that swing most amply, this is a book
on “normal” science, about which Alfred Tennyson once said: “science moves,
but slowly slowly, creeping on from point to point”, science closer to our scale,
science that used to be fundamental once, and is still fundamental in unraveling
all the complications left behind by those aspiring to reach the extremes. I shall
talk notonly aboutsuccesses, butalso aboutfailuresandcontroversies,whichare
unavoidablebecausescienceisdonebyhumans.
The two seeds of this book are my old book in Russian (Pismen, 1973) and
a lecture for an audience which theoretically had to encompasscivil servants and
bankers,butinfactconsistedlargelyofpeoplelikemyself,attheseminarorganized
bytheInstitutdel’Écolenormalesupérieurein2009,andlaterpublishedasabook
chapter (Rubio et al., 2013). No crystal is structured, however, in the same way
astheseedthathelpeditnucleate.Thisisnotanobjectiveaccount,butapersonal
storyofscienceintime,andglimpsesofmyownlifesometimesappearamongmore
importanttopics.
I dedicate this book to Hannah Timerman, my granddaughter,still a toddler at
thetimeofwriting,withthehopethatshere-readsit,oratleastpartofit,asanold
womanattheturnofthetwenty-secondcentury,andcontemplateshowthingshave
changedbythen.
Haifa,Israel LenPismen
2018
v
Contents
1 SwingsThroughtheAges........................................ 1
1.1 ComplexorSimple? ....................................... 1
1.2 SwingsofReligions........................................ 3
1.3 SwingsofElements ........................................ 5
1.4 SwingsofCosmology ...................................... 11
1.5 TheUnreasonableEfficiencyofMathematics .................. 18
1.6 Science,RevolutionaryandNormal........................... 20
2 ContinuumMechanics .......................................... 25
2.1 TheDryWateroftheAgeofEnlightenment ................... 25
2.2 HydrodynamicsAirborne ................................... 27
2.3 ViscosityandBoundaryLayers .............................. 30
2.4 Elasticity................................................. 33
2.5 Waves ................................................... 37
3 ContinuumBeyondMechanics................................... 41
3.1 StrikingaBalance ......................................... 41
3.2 TransportProcesses ........................................ 44
3.3 ChemicalReactions........................................ 46
3.4 ChargesandCurrents....................................... 50
3.5 PorousandGranularMedia ................................. 54
3.6 TheContinuumBreaksDown ............................... 57
4 FromContinuumtoAtoms ...................................... 59
4.1 JustaHypothesis? ......................................... 59
4.2 MolecularKinetics ........................................ 62
4.3 EntropyandtheArrowofTime .............................. 64
4.4 ChemicalBonds........................................... 66
4.5 ChemicalKinetics ......................................... 69
vii
viii Contents
5 CondensedMatter.............................................. 73
5.1 Crystals .................................................. 73
5.2 PhaseTransitions .......................................... 75
5.3 Surfaces.................................................. 79
5.4 Three-PhaseLines ......................................... 81
5.5 LiquidCrystals............................................ 83
5.6 Polymers................................................. 87
6 QuantumMatter ............................................... 89
6.1 TheNeedforQuanta ...................................... 89
6.2 QuantumWeirdness........................................ 92
6.3 ObjectionsandBypasses ................................... 95
6.4 ChemistryExplained ...................................... 97
6.5 EverydayQuantumDevices .................................102
6.6 QuantumCollectiveEffects .................................104
7 Brokensymmetry...............................................109
7.1 ConvectivePatterns ........................................109
7.2 ChemicalPatterns .........................................113
7.3 UnityinVariety ...........................................116
7.4 InstabilitiesThatNeverSaturate .............................120
8 ComplexitySimplified...........................................123
8.1 FromOrdertoChaos.......................................123
8.2 ToyModels...............................................124
8.3 TurbulenceMadeSimple ...................................129
8.4 ComplexityinModelEquations .............................131
9 ComplexityStrikesBack ........................................135
9.1 Turbulence ...............................................135
9.2 MechanicsandtheChemistryofLife .........................139
9.3 HeredityandEvolution ....................................144
9.4 Development .............................................149
9.5 ConsciousnessofElectrochemicalMachines ...................154
9.6 Environment..............................................157
10 QuoVadis? ....................................................161
10.1 WhereWeHaveGotto .....................................161
10.2 ScienceContemplatesSociety ...............................164
10.3 SocietyShapesScience.....................................167
10.4 TheEndofScience? .......................................172
References.........................................................175
IllustrationCredits .................................................185
Chapter 1
Swings Through the Ages
1.1 ComplexorSimple?
Therearemanydefinitionsofcomplexity,alloftheminadequate.“Anydefinitionof
complexityiscontextdependent,evensubjective”(Gell-Mann,1994).Wefeelintu-
itivelywhatiscomplexandwhatissimple–butperhapsitisanillusion?Acoder’s
measure of complexity is the length of a program that can simulate the system. Is
thatanygood?AJuliasetisgeneratedbyaveryshortprogramwhich,wheniterated,
givesaninfinitelyintricatepatternonaneverrefinedscale–lookingverycomplex
totheeye(Fig.1.1).IsE=mc2 complex?Itlookstobeaverysimpleformulathat
everylaypersonnowknows–sowhydidweneedanEinsteintocomeupwithit?–
butitsconsequencesmaybeverycomplex,evenlethal(thinkofHiroshima).
On the other hand, even a most astute hacker would get a headache trying to
code the most primitive hominid band. With no program available, how could we
decide when human society was more complex – now or twenty thousand years
ago?Certainly,everythingwassimpleroncewhenAdamwasemployedasahunter,
Eveasagatherer,andSnakeasashaman,whilenowwehaveabanker,agarbage
collector, a policeman, a social worker, a tennis player, a garage mechanic, and,
and, and ..., and all sorts of laws, and all kinds of infrastructure, and scientific,
pseudoscientific,andpopularjournals,andsocialmedia,and,and,and....Onthe
other hand, we all, or all those who enjoy or suffer this variety, live in the same
globalvillage,passthesamesecuritygatestoboardthesameplanes,evenspeakthe
same mongrel English with different accents, while back then one could possibly
walkthelengthofourweekenddrivetoencounterperhapsthesamelifestyle,buta
differentlanguageanddifferentspiritsanddifferentlegendsanddifferentgods.
Itisstillhardertodecidewhatweactuallyprefer–simpleorcomplex?Dowe
enjoyasimpleformulaoracomplexpicturethatitgenerates?Fromthebeginning
of civilization, humans tried to introduce order into the infinite complexity of the
surrounding world. This is what great ancient philosophers and great modern sci-
entistsaspiredtodo,frompre-SocraticstoAlbertEinstein,PaulDirac,andWerner
Heisenberg, vainly searching for a universal theory in their old age, to their living
© Springer Nature Switzerland AG 2018 1
L. Pismen, The Swings of Science,
https://doi.org/10.1007/978-3-319-99777-3_1
2 1 SwingsThroughtheAges
Fig.1.1 Juliaset
heirsstillengagedinthesamequest.Inthewordsofoneofthem,“simplicity,prop-
erlyunderstood,explainswhatitisthatmakesagoodexplanationdeep,elegant,and
beautiful”(Wilczek,2012).Ontheotherhand,totalitarianregimesofthe20thcen-
turytriedtorestrictthecomplexityofhumanthoughttosimplenotions,beitclass
or racial struggle, and to impose uniform order. This was no innovation, as Plato
aspiredtothesameinhisRepublic.Thetotalitarianorderinitssimplicityturnsout,
however,tobefragileandhardtosustaininthelongrun,asitgetsoverpoweredby
theeverpresentambientcomplexity,aswellasbytheinternalcomplexityofman,
who never stops at simple explanations and simple rules. Simplicity is properly
understood in conjunction with complexity. A universal theory breaks down in its
applicationsandextensionstotheinfinitephenomenologicalvarietyinthemidstof
whichweliveandwhichweenjoy,anditisthiscomplexitythatmakesitbeautiful.
BorisPasternakexpressedthiscontradiction:
Wecannotavoidfalling,asintoheresy,
intoanunheard-ofsimplicity.
Butwewillnotbesparedifwedonotconcealit:
peopleneeditmostofall,
buttheyunderstandcomplexitybetter.
People need simplicity, to grasp the essence of things, maybe in a single moment
ofrevelation–buttheyunderstandcomplexitybetter,havingevolvedtoendurethe
challengesofacomplexenvironment.Thisisthecauseofeternaloscillations,from
complexitytosimplicityandback.
1.2 SwingsofReligions 3
1.2 SwingsofReligions
Wecanalreadyseethisswingingmotion,fromcomplexitytosimplicityandback,in
theevolutionofreligions,whichhistoricallyservedinmanywaysthesameepiste-
mologicalpurposethatscienceisservingtoday(Ishallsaynothingabouttheother
functions of religion). Animism was the “infant philosophy of mankind” (Tylor,
1871).Therewasafairyineverytree,andanymphineverystream,andonecould
talk to them. The world around was brought to life by its spirits, just as we were,
andthecommonnatureofspirits,inanimate,living,anddead,explainedmysterious
phenomena, like the travels of the soul while dreaming. As individual spirits coa-
lesced into gods, like the spirits of trees into a god of the forest, their complexity
becamebetterorganized,butthesegodswerestillnotsofarremovedfromus.
Somegodsneednotbepraised,
theyareasequalwithyou,
andwithacarefulhand
youcanrearrangethem.(OsipMandelstam)
Therewasanenormousvarietyofthem,aseachhunter–gathererbandhadtheirown
guardiansandtheirownfavorites.
The complex world was taken as is, without our analytical insights. The world
wasaworldofmiracles,bothbeneficialandadverse.Wecallamiraclesomething
thatisbeautifulandunexpected,butwearenotaccustomedtomiraclesandwedo
not believe in them. Living in a world where miracles are common would be un-
comfortableanddangerous,likelivinginacountrywithnolaws.Magicalshamanic
ritualsservedbothtofederateatribeandtoobtainpracticalbenefitsbyplacatingthe
spiritsorgodsinthemysteriousirrationalworld.Aroughanalogywouldbebrib-
ingofficialstoadvanceouraimsortoavoidtrouble.Thishelpstoachievepractical
benefits,whiletheunlawfulworldremainsintact,miraculous,andmysterious.The
Fig.1.2 TheMagics