Physical computation : a mechanistic account

324 Pages·2018·2.177 MB·English

by  Piccinini, Gualtiero

Physical Computation

Physical Computation
A Mechanistic Account
Gualtiero Piccinini
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3
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Contents
Acknowledgements vii
Introduction 1
1. TowardsanAccountofPhysicalComputation 4
2. MappingAccounts 16
3. SemanticAccounts 26
4. Pancomputationalism 51
5. FromFunctionalAnalysistoMechanisticExplanation 74
6. TheOntologyofFunctionalMechanisms 100
7. TheMechanisticAccount 118
8. PrimitiveComponentsofComputingMechanisms 152
9. ComplexComponentsofComputingMechanisms 162
10. DigitalCalculators 176
11. DigitalComputers 181
12. AnalogComputers 198
13. ParallelComputersandNeuralNetworks 206
14. InformationProcessing 225
15. TheBoldPhysicalChurch-TuringThesis 244
16. TheModestPhysicalChurch-TuringThesis 263
Epilogue: TheNatureofComputation 274
Appendix:Computability 277
Bibliography 287
Index 307

Acknowledgements
I encountered the debate about the foundations of cognitive science when, as an
undergraduateattheUniversityofTurin,Itookanintroductorycourseincognitive
psychology taught by Bruno Bara. Those early wonderings eventually led to my
Ph.D.dissertationattheUniversityofPittsburgh,andthentoastreamofpaperson
computation and related topics. This book organizes, streamlines, revises, and
systematizesmostofwhatI’vethoughtandpublishedabout concretecomputation.
(Itleavesoutmyworkoncomputationaltheoriesofcognition.)
I could not have gotten where I am without the help of my teachers, beginning
with my parents and continuing all the way to my college and graduate school
teachers.Incollege,thefollowingwereespeciallyinfluential:inphilosophy,Elisabetta
Galeotti,DiegoMarconi,GianniVattimo,andCarloAugustoViano;inpsychology,
Bruno Bara and Giuliano Geminiani. In graduate school, the following played
importantrolesinmythinkingaboutcomputation:myadvisorPeterMachameras
wellasNuelBelnap,RobertDaley(ComputabilityTheory),BardErmentrout(Com-
putationalNeuroscience),JohnEarman,ClarkGlymour,PaulGriffiths,RickGrush,
KenManders,JohnNorton,andMerrileeSalmon.Otherimportantteachersduring
graduateschoolwereRobertBrandom,JoeCamp,AdolfGrünbaum,SusieJohnson
(Theory of Mind), Pat Levitt (Systems Neuroscience), Jay McClelland (Cognitive
Neuroscience), John McDowell, Ted McGuire, Robert Olby, Carl Olson (Cognitive
Neuroscience),FritzRinger,LauraRuetsche,andRichmondThomason.
Many people’s work shaped mine. On computation, the classic work of Alonzo
Church, Kurt Go¨del, Stephen Kleene, Emil Post, and Alan Turing was paramount.
On neural networks and their connection to digital computers, I learned the most
fromWarrenMcCulloch,WalterPitts,JohnvonNeumann,andNorbertWiener.On
analogcomputers,theworkofClaudeShannon,MarianPour-El,andLeeRubelwas
crucial. On artificial intelligence and computational cognitivescience, Allen Newell
and Herbert Simon had the largest impact. The canonical textbook on computer
organizationanddesignbyDavidPattersonandJohnHennessyconfirmedmyearly
hunchthatcomputationalexplanationismechanisticandhelpedmearticulateit.On
the philosophy of computation, I found most helpful the works of Jack Copeland,
RobertCummins,DanielDennett,FrancesEgan,JerryFodor,JustinGarson,Gilbert
Harman, John Haugeland, Zenon Pylyshyn, Oron Shagrir, Wilfried Sieg, and Ste-
phen Stich. On information, Fred Drestke and Claude Shannon were most signifi-
cant. On functions, Christopher Boorse and Ruth Millikan made the biggest
difference.Onmechanisms,IwasmostinfluencedbyCarlCraver,LindleyDarden,
PeterMachamer,andWilliamWimsatt.Ongeneralmetaphysics,JohnHeilandthe
NEHSummerSeminarhedirectedhelpedmeanenormousamount.
viii ACKNOWLEDGEMENTS
Theworkthatgoesintothisbookhasbenefitedfromsomanyinteractionswithso
many people over such a long time—including audiences at many talks—that
I cannot hope to remember everyone who played a role. I apologize in advance to
those I forget. Here arethose Iremember as most helpful:Darren Abramson,Fred
Adams, Neal Anderson, Ken Aizawa, Sonya Bahar, Mark Balaguer, Bill Bechtel,
Kenny Boyce, Dave Chalmers, Mark Collier, Carl Craver, Jack Copeland, Martin
Davis,DanielDennett,MichaelDickson,EliDresner,FrancesEgan,ChrisEliasmith,
IlkeErcan,CarrieFigdor,JerryFodor,FlorentFranchette,NirFresco,JustinGarson,
CarlGillett,RobertGordon,SabrinaHaimovici,GilbertHarman,JohnHeil,Alberto
Herna´ndez, David M. Kaplan, Saul Kripke, Fred Kroon, Bill Lycan, Corey Maley,
Marcin Milkowski, Jonathan Mills, Alex Morgan, Toby Ord, Anya Plutynski, Tom
Polger, Hilary Putnam, Michael Rabin, Michael Rescorla, Brendan Ritchie, Brad
Rives, Martin Roth, Anna-Mari Rusanen, Dan Ryder, Andrea Scarantino, Matthias
Scheutz,SusanSchneider,SamScott,LarryShapiro,RebeccaSkloot,MarkSprevak,
OronShagrir,StuartShapiro,DoronSwade,Wilfried Sieg,EricThomson,Brandon
Towl,RayTurner,DanWeiskopf,andJulieYoo.
Special thanks to Mark Sprevak, the members of the reading group he ran on a
previous version of the manuscript, and an anonymous referee for OUP for their
extremelyhelpfulfeedback.ThankstoPeterMomtchiloff,myeditoratOUP,forhis
help,patience,andsupport.
Chapters 1–4 are indebted to G. Piccinini, “Computation in Physical Systems,”
TheStanfordEncyclopediaofPhilosophy(Fall2010Edition),EdwardN.Zalta(ed.),
URL=http://plato.stanford.edu/archives/fall2010/entries/computation-physicalsystems/
Chapter1 is indebted to G. Piccinini, “Computing Mechanisms,” Philosophy of
Science,74.4(2007),501–26.
Chapter3 is indebted to G. Piccinini, “Computation without Representation,”
PhilosophicalStudies,137.2(2008),205–41andG.Piccinini,“Functionalism,Com-
putationalism, and Mental Contents,” Canadian Journal of Philosophy, 34.3 (2004),
375–410.
Chapter4 is indebted to G. Piccinini, “Computational Modeling vs. Computa-
tional Explanation: Is Everything a Turing Machine, and Does It Matter to the
PhilosophyofMind?”AustralasianJournalofPhilosophy,85.1(2007),93–115.
Chapter5 is indebted to G. Piccinini, “Functionalism, Computationalism, and
Mental States,” Studies in the History and Philosophy of Science, 35.4 (2004),
811–33andG.PiccininiandC.Craver, “IntegratingPsychology andNeuroscience:
FunctionalAnalysesasMechanismSketches,”Synthese,183.3(2011),283–311.
Chapter6 is indebted to C. Maley and G. Piccinini, “A Unified Mechanistic
Account of Teleological Functions for Psychology and Neuroscience,” forthcoming
in David Kaplan, ed., Integrating Psychology and Neuroscience: Prospects and Prob-
lems.Oxford:OxfordUniversityPress.
OUPCORRECTEDPROOF–FINAL,30/4/2015,SPi
ACKNOWLEDGEMENTS ix
Chapter7 is indebted to G. Piccinini, “Computing Mechanisms,” Philosophy of
Science, 74.4 (2007), 501–26 and G. Piccinini, “Computation without Representa-
tion,”PhilosophicalStudies,137.2(2008),205–41.
Chapters 10–13 are indebted to G. Piccinini, “Computers,” Pacific Philosophical
Quarterly,89.1(2008),32–73.
Chapter13isindebtedtoG.Piccinini,“SomeNeuralNetworksCompute,Others
Don’t,”NeuralNetworks,21.2–3(2008),311–21.
Chapter14isindebtedtoG.PiccininiandA.Scarantino,“InformationProcessing,
Computation,andCognition,”JournalofBiologicalPhysics,37.1(2011),1–38.
Chapters15and16areindebtedto“ThePhysicalChurch-TuringThesis:Modest
orBold?”TheBritishJournalforthePhilosophyofScience,62.4(2011),733–69.
My co-authors for some of the above articles—Carl Craver, Corey Maley, and
AndreaScarantino—helpedmedevelopimportantaspectsoftheviewIdefendand
Iamdeeplygratefultothem.
The articles from which the book borrows were usually refereed anonymously.
Thankstothemanyanonymousrefereesfortheirhelpfulfeedback.
Thanks to my research assistant, Frank Faries, especially for drawing the figures
forChapters8and9.
ThismaterialisbasedonworksupportedbytheCollegeofArtsandSciencesatthe
University of Missouri—St. Louis, the Charles Babbage Institute, the Institute for
AdvancedStudiesattheHebrewUniversityofJerusalem,theNationalEndowment
fortheHumanities,theNationalScienceFoundationundergrantsno.SES-0216981
andSES-0924527,theUniversityofMissouri,theUniversityofMissouri—St.Louis,
theMellonFoundation,andtheRegioneSardegna.Anyopinions,findings, conclu-
sions, and recommendations expressed in this book arethose of the author and do
notnecessarilyreflecttheviewsofthesefundinginstitutions.
Deepthankstomyfriends,partners,andfamily—myparents,sisters,brothers-in-
law, and nieces—for their love and support, especially during my most challenging
times. Thanks to my daughters—Violet, Brie, and Martine—for bringing so much
meaningandjoytomylife.