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Philosophers

Mortimer Adler
Rogers Albritton
Alexander of Aphrodisias
Samuel Alexander
William Alston
Anaximander
G.E.M.Anscombe
Anselm
Louise Antony
Thomas Aquinas
Aristotle
David Armstrong
Harald Atmanspacher
Robert Audi
Augustine
J.L.Austin
A.J.Ayer
Alexander Bain
Mark Balaguer
Jeffrey Barrett
William Barrett
William Belsham
Henri Bergson
George Berkeley
Isaiah Berlin
Richard J. Bernstein
Bernard Berofsky
Robert Bishop
Max Black
Susanne Bobzien
Emil du Bois-Reymond
Hilary Bok
Laurence BonJour
George Boole
Émile Boutroux
Daniel Boyd
F.H.Bradley
C.D.Broad
Michael Burke
Lawrence Cahoone
C.A.Campbell
Joseph Keim Campbell
Rudolf Carnap
Carneades
Nancy Cartwright
Gregg Caruso
Ernst Cassirer
David Chalmers
Roderick Chisholm
Chrysippus
Cicero
Randolph Clarke
Samuel Clarke
Anthony Collins
Antonella Corradini
Diodorus Cronus
Jonathan Dancy
Donald Davidson
Mario De Caro
Democritus
Daniel Dennett
Jacques Derrida
René Descartes
Richard Double
Fred Dretske
John Dupré
John Earman
Laura Waddell Ekstrom
Epictetus
Epicurus
Austin Farrer
Herbert Feigl
Arthur Fine
John Martin Fischer
Frederic Fitch
Owen Flanagan
Luciano Floridi
Philippa Foot
Alfred Fouilleé
Harry Frankfurt
Richard L. Franklin
Bas van Fraassen
Michael Frede
Gottlob Frege
Peter Geach
Edmund Gettier
Carl Ginet
Alvin Goldman
Gorgias
Nicholas St. John Green
H.Paul Grice
Ian Hacking
Ishtiyaque Haji
Stuart Hampshire
W.F.R.Hardie
Sam Harris
William Hasker
R.M.Hare
Georg W.F. Hegel
Martin Heidegger
Heraclitus
R.E.Hobart
Thomas Hobbes
David Hodgson
Shadsworth Hodgson
Baron d'Holbach
Ted Honderich
Pamela Huby
David Hume
Ferenc Huoranszki
Frank Jackson
William James
Lord Kames
Robert Kane
Immanuel Kant
Tomis Kapitan
Walter Kaufmann
Jaegwon Kim
William King
Hilary Kornblith
Christine Korsgaard
Saul Kripke
Thomas Kuhn
Andrea Lavazza
Christoph Lehner
Keith Lehrer
Gottfried Leibniz
Jules Lequyer
Leucippus
Michael Levin
Joseph Levine
George Henry Lewes
C.I.Lewis
David Lewis
Peter Lipton
C. Lloyd Morgan
John Locke
Michael Lockwood
Arthur O. Lovejoy
E. Jonathan Lowe
John R. Lucas
Lucretius
Alasdair MacIntyre
Ruth Barcan Marcus
Tim Maudlin
James Martineau
Nicholas Maxwell
Storrs McCall
Hugh McCann
Colin McGinn
Michael McKenna
Brian McLaughlin
John McTaggart
Paul E. Meehl
Uwe Meixner
Alfred Mele
Trenton Merricks
John Stuart Mill
Dickinson Miller
G.E.Moore
Thomas Nagel
Otto Neurath
Friedrich Nietzsche
John Norton
P.H.Nowell-Smith
Robert Nozick
William of Ockham
Timothy O'Connor
Parmenides
David F. Pears
Charles Sanders Peirce
Derk Pereboom
Steven Pinker
Plato
Karl Popper
Porphyry
Huw Price
H.A.Prichard
Protagoras
Hilary Putnam
Willard van Orman Quine
Frank Ramsey
Ayn Rand
Michael Rea
Thomas Reid
Charles Renouvier
Nicholas Rescher
C.W.Rietdijk
Richard Rorty
Josiah Royce
Bertrand Russell
Paul Russell
Gilbert Ryle
Jean-Paul Sartre
Kenneth Sayre
T.M.Scanlon
Moritz Schlick
Arthur Schopenhauer
John Searle
Wilfrid Sellars
Alan Sidelle
Ted Sider
Henry Sidgwick
Walter Sinnott-Armstrong
J.J.C.Smart
Saul Smilansky
Michael Smith
Baruch Spinoza
L. Susan Stebbing
Isabelle Stengers
George F. Stout
Galen Strawson
Peter Strawson
Eleonore Stump
Francisco Suárez
Richard Taylor
Kevin Timpe
Mark Twain
Peter Unger
Peter van Inwagen
Manuel Vargas
John Venn
Kadri Vihvelin
Voltaire
G.H. von Wright
David Foster Wallace
R. Jay Wallace
W.G.Ward
Ted Warfield
Roy Weatherford
C.F. von Weizsäcker
William Whewell
Alfred North Whitehead
David Widerker
David Wiggins
Bernard Williams
Timothy Williamson
Ludwig Wittgenstein
Susan Wolf

Scientists

David Albert
Michael Arbib
Walter Baade
Bernard Baars
Jeffrey Bada
Leslie Ballentine
Marcello Barbieri
Gregory Bateson
Horace Barlow
John S. Bell
Mara Beller
Charles Bennett
Ludwig von Bertalanffy
Susan Blackmore
Margaret Boden
David Bohm
Niels Bohr
Ludwig Boltzmann
Emile Borel
Max Born
Satyendra Nath Bose
Walther Bothe
Jean Bricmont
Hans Briegel
Leon Brillouin
Stephen Brush
Henry Thomas Buckle
S. H. Burbury
Melvin Calvin
Donald Campbell
Sadi Carnot
Anthony Cashmore
Eric Chaisson
Gregory Chaitin
Jean-Pierre Changeux
Rudolf Clausius
Arthur Holly Compton
John Conway
Jerry Coyne
John Cramer
Francis Crick
E. P. Culverwell
Antonio Damasio
Olivier Darrigol
Charles Darwin
Richard Dawkins
Terrence Deacon
Lüder Deecke
Richard Dedekind
Louis de Broglie
Stanislas Dehaene
Max Delbrück
Abraham de Moivre
Bernard d'Espagnat
Paul Dirac
Hans Driesch
John Eccles
Arthur Stanley Eddington
Gerald Edelman
Paul Ehrenfest
Manfred Eigen
Albert Einstein
George F. R. Ellis
Hugh Everett, III
Franz Exner
Richard Feynman
R. A. Fisher
David Foster
Joseph Fourier
Philipp Frank
Steven Frautschi
Edward Fredkin
Benjamin Gal-Or
Howard Gardner
Lila Gatlin
Michael Gazzaniga
Nicholas Georgescu-Roegen
GianCarlo Ghirardi
J. Willard Gibbs
James J. Gibson
Nicolas Gisin
Paul Glimcher
Thomas Gold
A. O. Gomes
Brian Goodwin
Joshua Greene
Dirk ter Haar
Jacques Hadamard
Mark Hadley
Patrick Haggard
J. B. S. Haldane
Stuart Hameroff
Augustin Hamon
Sam Harris
Ralph Hartley
Hyman Hartman
Jeff Hawkins
John-Dylan Haynes
Donald Hebb
Martin Heisenberg
Werner Heisenberg
John Herschel
Basil Hiley
Art Hobson
Jesper Hoffmeyer
Don Howard
John H. Jackson
William Stanley Jevons
Roman Jakobson
E. T. Jaynes
Pascual Jordan
Eric Kandel
Ruth E. Kastner
Stuart Kauffman
Martin J. Klein
William R. Klemm
Christof Koch
Simon Kochen
Hans Kornhuber
Stephen Kosslyn
Daniel Koshland
Ladislav Kovàč
Leopold Kronecker
Rolf Landauer
Alfred Landé
Pierre-Simon Laplace
Karl Lashley
David Layzer
Joseph LeDoux
Gerald Lettvin
Gilbert Lewis
Benjamin Libet
David Lindley
Seth Lloyd
Hendrik Lorentz
Werner Loewenstein
Josef Loschmidt
Ernst Mach
Donald MacKay
Henry Margenau
Owen Maroney
David Marr
Humberto Maturana
James Clerk Maxwell
Ernst Mayr
John McCarthy
Warren McCulloch
N. David Mermin
George Miller
Stanley Miller
Ulrich Mohrhoff
Jacques Monod
Vernon Mountcastle
Emmy Noether
Donald Norman
Alexander Oparin
Abraham Pais
Howard Pattee
Wolfgang Pauli
Massimo Pauri
Wilder Penfield
Roger Penrose
Steven Pinker
Colin Pittendrigh
Walter Pitts
Max Planck
Susan Pockett
Henri Poincaré
Daniel Pollen
Ilya Prigogine
Hans Primas
Zenon Pylyshyn
Henry Quastler
Adolphe Quételet
Pasco Rakic
Nicolas Rashevsky
Lord Rayleigh
Frederick Reif
Jürgen Renn
Giacomo Rizzolati
Emil Roduner
Juan Roederer
Jerome Rothstein
David Ruelle
David Rumelhart
Tilman Sauer
Ferdinand de Saussure
Jürgen Schmidhuber
Erwin Schrödinger
Aaron Schurger
Sebastian Seung
Thomas Sebeok
Franco Selleri
Claude Shannon
Charles Sherrington
David Shiang
Abner Shimony
Herbert Simon
Dean Keith Simonton
Edmund Sinnott
B. F. Skinner
Lee Smolin
Ray Solomonoff
Roger Sperry
John Stachel
Henry Stapp
Tom Stonier
Antoine Suarez
Leo Szilard
Max Tegmark
Teilhard de Chardin
Libb Thims
William Thomson (Kelvin)
Richard Tolman
Giulio Tononi
Peter Tse
Alan Turing
Francisco Varela
Vlatko Vedral
Mikhail Volkenstein
Heinz von Foerster
Richard von Mises
John von Neumann
Jakob von Uexküll
C. S. Unnikrishnan
C. H. Waddington
John B. Watson
Daniel Wegner
Steven Weinberg
Paul A. Weiss
Herman Weyl
John Wheeler
Wilhelm Wien
Norbert Wiener
Eugene Wigner
E. O. Wilson
Günther Witzany
Stephen Wolfram
H. Dieter Zeh
Semir Zeki
Ernst Zermelo
Wojciech Zurek
Konrad Zuse
Fritz Zwicky

Presentations

Biosemiotics
Free Will
Mental Causation
James Symposium
 
Stephen Wolfram
Stephen Wolfram is a physicist, computer scientist, and very successful businessman.

In his 2002 book, A New Kind of Science, Wolfram published a simpler example of a universal computer (Turing machine). Wolfram's cellular automata model superceded Marvin Minsky' s 1962 Turing machine, which had held the record of simplest universal computer for 40 years.

Wolfram is the chief executive of Wolfram Research, which developed technical computing tools applicable to machine learning, neural networks, image processing and visualizations.

His Wolfram Alpha is a free online answer service that goes beyond typical Internet searches that return web pages that may have the answers.

Wolfram calls Alpha a "computational knowledge engine" or "answer engine." Alpha assembles the best possible answer from curated data. Alpha answers consist of text and related data visualizations.

Difficult questions asked of Apple's Siri and Amazon's Alexa are often forwarded to Wolfram Alpha for more significant answers.

Wolfram is part of a group of scientists who work in "digital philosophy." They include Gregory Chaitin, Edward Fredkin, Seth Lloyd, Rudy Rucker, Jürgen Schmidhuber, Konrad Zuse, and Wolfram.

Digital philosophers generally hope to reduce the mind to a computer and even see the whole universe as a computer running some kind of cosmic code.

Stephen Wolfram and Frederick Reif

Frederick "Fred" Reif earned his Ph.D in physics from Harvard University in 1953, with Ed Purcell as his thesis adviser. He went to work with Enrico Fermi at the University of Chicago. Seven years later, he went to the University of California, Berkeley, where he taught for twenty-nine years. At Berkeley he authored a classic text in statistical physics and thermodynamics, Statistical and Thermal Physics, published in 1965.

At that time, the National Science Foundation supported the development of more modern textbook series in the physical sciences aimed at high schools students. At MIT, Jerrold Zacharias led the Physical Science Study Committee. At Harvard, Gerald Holton and Fletcher Watson led Project Physics. At Berkeley, Reif rewrote his textbook, titled simply Statistical Physics, as volume 5 of the Berkeley Physics Course.

Reif's book incorporated the first sophisticated computer calculations of the motions of gas molecules. As such, it was a landmark in the field of computational methods for solving problems in physics as opposed to solving mathematical differential equations.

Reif's work was a visualization of the second law of thermodynamics. Reif's movie frames led Wolfram to develop his "New Kind of Science" using computational principles to derive the fundamental laws of physics, as described in Wolfram's latest book The Second Law.

Displayed as frames in a movie film, the book's front cover illustrated the diffusion of molecules from an initial state concentrated in the left half of a two-dimensional space to filling the whole space after seven frames.

On the back cover, the velocities of all the particles were reversed and the computer calculations show the molecules making their way back into the left half. But they do not return to the exact original positions, due to "round-off errors" in the calculations.

In principle, if the computer could have unlimited information about the positions and velocities (an infinite number of significant figures), all the molecule positions in the past and the future could be determined by Newton's laws of motion (F=ma, etc.). Classical physics is deterministic.

In 1814, Pierre-Simon Laplace wrote in the introduction to his Essai philosophique sur les probabilités,

"We may regard the present state of the universe as the effect of its past and the cause of its future. An intellect which at a certain moment would know all forces that set nature in motion, and all positions of all items of which nature is composed, if this intellect were also vast enough to submit these data to analysis, it would embrace in a single formula the movements of the greatest bodies of the universe and those of the tiniest atom; for such an intellect nothing would be uncertain and the future just like the past would be present before its eyes."

LaPlace was extending an earlier idea of Newton's contemporary Gottfried Leibniz, but it became famous as Laplace's Demon, a key concept of strict physical determinism.

In his latest book, The Second Law, Stephen Wolfram says he spent fifty years trying to understand the deep physical significance of Reif's movie frames and the computations that produced them.

The great question for Wolfram, and for Reif, is this: if the equations of motion for microscopic collisions between gas particles are reversible, why are the macroscopic properties of gases irreversible, for example the entropy can only increase, never decrease, as the second law claims.

In a recent YouTube video, Wolfram described the problem,

And in The Second Law (p.219), Wolfram describes Fred's book that started his fifty-year quest to understand the second law.

The Backstory of the Book Cover That Started It All

What is the backstory of the book cover that launched my long journey with the Second Law? The book was published in 1965, and inside its front flap we find:

The book covers

The movie strips on the covers illustrate the fundamental ideas of irreversibility and fluctuations by showing the motion of 40 particles inside a two-dimensional box. The movie strips were produced by an electronic computer programmed to calculate particle trajectories. (For details, see pp. 7, 24, and 25 inside the book.) The front cover illustrates the irreversible approach to equilibrium starting from the highly nonrandom initial situation where all the particles are located in the left half of the box. The back cover (read in the upward direction from bottom to top) illustrates the irreversible approach to equilibrium if, starting from the initial situation at the top of the front cover, all the particle velocities are reversed (or equivalently, if the direction of time is imagined to be reversed). The back-cover and front-cover movie strips together, read consecutively in the downward direction, illustrate a very large fluctuation occurring extremely rarely in equilibrium.

Wolfram designed the covers of his book to match the look of Fred's book, but with the computer calculations likely redone using his Mathematica and Wolfram Language tools, or perhaps the evolving hypergraphs of his cellular automata?

Is Physics Reversible or Irreversible?
The answer hinges on the question of fundamental randomness. Ludwig Boltzmann hypothesized there is some unknown process causing random behavior in the gas molecules that he called "molecular disorder" (molekular ungeordnete).

Since Newton's microscopic laws of motion of the gas particles are completely deterministic and time reversible, the great question for the past one-hundred and fifty years is how macroscopically, the gas appears to be irreversible.

What can we say about the views of Fred Reif and Stephen Wolfram on the questions of randomness and reversibility? We can actually tell a lot by looking very carefully at the results of their computer calculations shown on the front and back covers of their books.

Here are the front cover and back cover movie strips side by side.

Reif Statistical Physics
Wolfram The Second Law

Let's now carefully compare the starting frame on the front covers to the ending frame on the back covers. What can we say about the physics?

Both back covers start by reversing the velocities of the molecules in the last frame on the front cover. Wolfram shows that explicitly by reversing the little white arrows.

Both evolve back to the left half of the frames, as if time itself was being reversed.

But note that Reif's computations do not return each molecule back to its exact starting position, as do Wolfram's. Wolfram's molecules are in a rigid grid pattern, initially four rows of three squares, perhaps an artifact of his cellular automata? Note that the back cover unfortunately cuts off the bottom row of four molecules.

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