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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
F.H.Bradley
C.D.Broad
Michael Burke
Lawrence Cahoone
C.A.Campbell
Joseph Keim Campbell
Rudolf Carnap
Carneades
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
Herbert Feigl
Arthur Fine
John Martin Fischer
Frederic Fitch
Owen Flanagan
Luciano Floridi
Philippa Foot
Alfred Fouilleé
Harry Frankfurt
Richard L. Franklin
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
William James
Lord Kames
Robert Kane
Immanuel Kant
Tomis Kapitan
Walter Kaufmann
Jaegwon Kim
William King
Hilary Kornblith
Christine Korsgaard
Saul Kripke
Andrea Lavazza
Christoph Lehner
Keith Lehrer
Gottfried Leibniz
Jules Lequyer
Leucippus
Michael Levin
George Henry Lewes
C.I.Lewis
David Lewis
Peter Lipton
C. Lloyd Morgan
John Locke
Michael Lockwood
E. Jonathan Lowe
John R. Lucas
Lucretius
Alasdair MacIntyre
Ruth Barcan Marcus
James Martineau
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

Michael Arbib
Walter Baade
Bernard Baars
Leslie Ballentine
Gregory Bateson
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
Hans Briegel
Leon Brillouin
Stephen Brush
Henry Thomas Buckle
S. H. Burbury
Donald Campbell
Anthony Cashmore
Eric Chaisson
Gregory Chaitin
Jean-Pierre Changeux
Arthur Holly Compton
John Conway
John Cramer
Francis Crick
E. P. Culverwell
Olivier Darrigol
Charles Darwin
Richard Dawkins
Terrence Deacon
Lüder Deecke
Richard Dedekind
Louis de Broglie
Max Delbrück
Abraham de Moivre
Paul Dirac
Hans Driesch
John Eccles
Arthur Stanley Eddington
Gerald Edelman
Paul Ehrenfest
Albert Einstein
Hugh Everett, III
Franz Exner
Richard Feynman
R. A. Fisher
Joseph Fourier
Philipp Frank
Steven Frautschi
Edward Fredkin
Lila Gatlin
Michael Gazzaniga
GianCarlo Ghirardi
J. Willard Gibbs
Nicolas Gisin
Paul Glimcher
Thomas Gold
A. O. Gomes
Brian Goodwin
Joshua Greene
Jacques Hadamard
Mark Hadley
Patrick Haggard
Stuart Hameroff
Augustin Hamon
Sam Harris
Hyman Hartman
John-Dylan Haynes
Donald Hebb
Martin Heisenberg
Werner Heisenberg
John Herschel
Art Hobson
Jesper Hoffmeyer
E. T. Jaynes
William Stanley Jevons
Roman Jakobson
Pascual Jordan
Ruth E. Kastner
Stuart Kauffman
Martin J. Klein
William R. Klemm
Christof Koch
Simon Kochen
Hans Kornhuber
Stephen Kosslyn
Ladislav Kovàč
Leopold Kronecker
Rolf Landauer
Alfred Landé
Pierre-Simon Laplace
David Layzer
Benjamin Libet
Seth Lloyd
Hendrik Lorentz
Josef Loschmidt
Ernst Mach
Donald MacKay
Henry Margenau
James Clerk Maxwell
Ernst Mayr
John McCarthy
Warren McCulloch
Ulrich Mohrhoff
Jacques Monod
Emmy Noether
Abraham Pais
Howard Pattee
Wolfgang Pauli
Massimo Pauri
Roger Penrose
Steven Pinker
Colin Pittendrigh
Max Planck
Susan Pockett
Henri Poincaré
Daniel Pollen
Ilya Prigogine
Hans Primas
Adolphe Quételet
Jürgen Renn/a>
Juan Roederer
Jerome Rothstein
David Ruelle
Tilman Sauer
Jürgen Schmidhuber
Erwin Schrödinger
Aaron Schurger
Claude Shannon
David Shiang
Herbert Simon
Dean Keith Simonton
B. F. Skinner
Lee Smolin
Ray Solomonoff
Roger Sperry
John Stachel
Henry Stapp
Tom Stonier
Antoine Suarez
Leo Szilard
Max Tegmark
William Thomson (Kelvin)
Giulio Tononi
Peter Tse
Vlatko Vedral
Heinz von Foerster
John von Neumann
John B. Watson
Daniel Wegner
Steven Weinberg
Paul A. Weiss
John Wheeler
Wilhelm Wien
Norbert Wiener
Eugene Wigner
E. O. Wilson
Stephen Wolfram
H. Dieter Zeh
Ernst Zermelo
Wojciech Zurek
Konrad Zuse
Fritz Zwicky

Presentations

Biosemiotics
Free Will
Mental Causation
James Symposium
 
Warren McCulloch
Warren McCulloch spent most of his life arguing that neurons in the brain are logic gates like those in digital computers, and that the brain can be understood as a Turing machine (a universal digital computer).

McCulloch and Pitts were thus the originators of today's widely supported "computational model of the mind." Their work inspired theories of "cellular automata," in which individual cells live or die according to inputs from their surrounding cells. See John Conway's "Game of Life."

In their 1943 paper, "A Logical Calculus of the Ideas Immanent in Nervous Activity," McCulloch and his younger colleague Walter Pitts wrote

Because of the “all-or-none” character of nervous activity, neural events and the relations among them can be treated by means of propositional logic. It is found that the behavior of every net can be described in these terms, with the addition of more complicated logical means for nets containing circles; and that for any logical expression satisfying certain conditions, one can find a net behaving in the fashion it describes. It is shown that many particular choices among possible neurophysiological assumptions are equivalent, in the sense that for every net behaving under one assumption, there exists another net which behaves under the other and gives the same results, although perhaps not in the same time. Various applications of the calculus are discussed.

McCulloch says his ideas that neural networks are similar to arguments in propositional logic and thus to computer networks dates back many years.

Many years ago one of us, by considerations impertinent to this argument, was led to conceive of the response of any neuron as factually equivalent to a proposition which proposed its adequate stimulus. He therefore attempted to record the behavior of complicated nets in the notation of the symbolic logic of propositions. The “all-or-none” law of nervous activity is sufficient to insure that the activity of any neuron may be represented as a proposition. Physiological relations existing among nervous activities correspond, of course, to relations among the propositions; and the utility of the representation depends upon the identity of these relations with those of the logic of propositions. To each reaction of any neuron there is a corresponding assertion of a simple proposition. This, in turn, implies either some other simple proposition or the disjunction of the conjunction, with or without negation, of similar propositions, according to the configuration of the synapses upon and the threshold of the neuron in question.
In the 1930's McCulloch had studied logic at Yale in Frederic Fitch's course on propositional logic, based on the great Principia Mathematica of Bertrand Russell and Alfred North Whitehead.

Fitch also was the thesis adviser for Ruth Barcan Marcus, whose work on the "necessity of identity" influenced Saul Kripke.

Despite the fact that information flows along neurons in the brain, the neural network is not a computer network, brain processes are not algorithms, there is no central processing unit (CPU) or even distributed parallel processing.

Very simply, man is not a machine and the brain is not a computer.

Nevertheless, we can regard McCulloch as the first thinker to offer a solution to the mind-body problem that "embodies" an immaterial logical software mind in a material mechanical hardware computer, as the title of his 1965 book, "Embodiments of Mind, suggests.

The Macy Conferences

McCulloch was a central organizer and frequently the chair of the Macy Conferences on Cybernetics held in the late 1940's an early 1950's. Their initial title was "Feedback Mechanisms and Circular Causal Systems in Biological and Social Systems."

At the first conference in 1946 McCulloch gave a presentation on how simulated neural networks can emulate the calculus of propositional logic. He also drew attention to communication as a descriptive metaphor and noted the differences between descriptions of messages' mechanics and message content or meaning. He suggests memory may be a function of continuous cyclical impulses in a neural network. He described causal "circles" in neural networks as continuous loops that could reverberate indefinitely and be a possible location for memories.

At the third conference (1947) McCulloch began collating and distributing a summary report on the conference.

Earlier conferences had not been adequately documented. McCulloch attempted to summarize the key points of the first 3 conferences following the third event, then distributed this to the attendees. With the exception of Margaret Mead's shorthand notes (indecipherable owing to her personal shorthand coding) and the fragmentary results of the earlier crude recording / transcription efforts, McCulloch's retrospective remains the main documentation for the first 3 conferences.

At the final 10th conference McCulloch presented his work with Walter Pitts on how neural mechanisms can recognize shapes and musical chords. He cites strong arguments from others rebutting this work, and ends with a good-natured concession that his and Pitts' efforts have been in the fine tradition of scientific refutability. (This incident is a poignant event, in that at the time it seemed to indicate one of the project streams feeding the Macy Conferences had in fact turned out to be a dead end.)

McCulloch was tasked to write a final summarization of the consensus achieved during the 10 Macy Conferences. This proved difficult, because by this time it's clear that the cybernetics group is moving (and has always moved) in several different directions. McCulloch writes in part: "Our most notable agreement is that we have learned to know one another a bit better, and to fight fair in our shirt sleeves." (Transactions, p. 69)

As chairperson for all 10 Macy Conferences, McCulloch no doubt desired to portray the series as having produced something. His concession of what can only be called a social networking outcome illustrates how the Macy Conferences could not even then be construed as having produced a unified theory or meta-discipline.

In 1959, McCulloch and Pitts collaborated with Jerome Lettvin and Humberto Maturana to write the classic paper "What the Frog's Eye Tells the Frog's Brain," which was reprinted in McCulloch' classic "Embodiments of Mind" in 1965.

This work was a great disappointment for McCulloch, perhaps more for Pitts, because the actions of the frog were dependent on the patterns of light falling on the frog's retina, long before any digital or logical information processing could occur in the brain behind the eye.

What are the consequences of this work? Fundamentally, it shows that the eye speaks to the brain in a language already highly organized and interpreted, instead of transmitting some more or less accurate copy of the distribution of light on the receptors

Although these operations have been encoded genetically in the frog as a species, it is an example of successful experiences with bugs in the frog's ancestors being recorded in the brain, and the reproduction of the successful actions (tongue reaching out toward a bug) when a sufficiently similar visual experience presents itself.

See our Experience Recorder and Reproducer

The operations thus have much more the flavor of perception than of sensation if that distinction has any meaning now. That is to say that the language in which they are best described is the language of complex abstractions from the visual image. We have been tempted, for example, to call the convexity detectors "bug perceivers." Such a fiber responds best when a dark object, smaller than a receptive field, enters that field, stops, and moves about intermittently thereafter. The response is not affected if the lighting changes or if the background (say a picture of grass and flowers) is moving, and is not there if only the background, moving or still, is in the field. Could one better describe a system for detecting an accessible bug?

References
A Logical Calculus of the Ideas Immanent in Nervous Activity, Bulletin of Mathematical Biophysics, Vol.5, 1943, pp.115-133

What the Frog's Eye Tells the Frog's Brain, Proceedings of the IRE, 1959, p.1940

The Man Who Tried to Redeem the World with Logic, by Amanda Gefter.

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