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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 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
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
John Martin Fischer
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
Jaegwon Kim
William King
Hilary Kornblith
Christine Korsgaard
Saul Kripke
Andrea Lavazza
Keith Lehrer
Gottfried Leibniz
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
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
William Whewell
Alfred North Whitehead
David Widerker
David Wiggins
Bernard Williams
Timothy Williamson
Ludwig Wittgenstein
Susan Wolf

Scientists

Michael Arbib
Bernard Baars
Gregory Bateson
John S. Bell
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
Jean-Pierre Changeux
Arthur Holly Compton
John Conway
John Cramer
E. P. Culverwell
Charles Darwin
Terrence Deacon
Louis de Broglie
Max Delbrück
Abraham de Moivre
Paul Dirac
Hans Driesch
John Eccles
Arthur Stanley Eddington
Paul Ehrenfest
Albert Einstein
Hugh Everett, III
Franz Exner
Richard Feynman
R. A. Fisher
Joseph Fourier
Lila Gatlin
Michael Gazzaniga
GianCarlo Ghirardi
J. Willard Gibbs
Nicolas Gisin
Paul Glimcher
Thomas Gold
A.O.Gomes
Brian Goodwin
Joshua Greene
Jacques Hadamard
Patrick Haggard
Stuart Hameroff
Augustin Hamon
Sam Harris
Hyman Hartman
John-Dylan Haynes
Martin Heisenberg
Werner Heisenberg
John Herschel
Jesper Hoffmeyer
E. T. Jaynes
William Stanley Jevons
Roman Jakobson
Pascual Jordan
Ruth E. Kastner
Stuart Kauffman
Martin J. Klein
Simon Kochen
Stephen Kosslyn
Ladislav Kovàč
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
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
Juan Roederer
Jerome Rothstein
David Ruelle
Erwin Schrödinger
Aaron Schurger
Claude Shannon
David Shiang
Herbert Simon
Dean Keith Simonton
B. F. Skinner
Roger Sperry
John Stachel
Henry Stapp
Tom Stonier
Antoine Suarez
Leo Szilard
William Thomson (Kelvin)
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
H. Dieter Zeh
Ernst Zermelo
Wojciech Zurek

Presentations

Biosemiotics
Free Will
Mental Causation
James Symposium
 
Donald MacKay

Donald MacKay was a British physicist who made important contributions to cybernetics and the question of "meaning" in information theory.

MacKay contributed to the London Symposia on Information Theory and attended the eighth Macy Conference on Cybernetics in New York in 1951 where he met Gregory Bateson, Warren McCulloch, I. A. Richards, and Claude Shannon.

Roman Jakobson, who attended the eighth Macy Conference, and attended some London Symposia, encouraged MacKay to publish a collection of his several essays on Information and Meaning that had been published between 1950 and 1960.

They contain the first, and in many ways, the clearest account of how to add "meaning" to information theory, in light of Shannon's warning that his work was a theory of "communication" only, completely independent of the meaning in a message. Here is Shannon's famous sender-receiver diagram.

Jakobson added the "context" of a message to Shannon's diagram, so was in an excellent position to appreciate MacKay's work. Here is Jakobson's addition of context.

Context was perhaps Jakobson's most important addition to semiotics. Adding context gives us the difference between semantics (the standard dictionary meaning of a word according to the normal "rules" of the language) versus pragmatics, the meaning that may be intended by the sender, or should be inferred by the receiver/interpreter because of the current situation. Jakobson calls this contextual information "denotative," "cognitive," "referential," the "leading task" of a message. Context-dependence alters the "meaning" to suit the purpose of a communication.

MacKay's earliest work, at the end of World War II, behaviour of electrical pulses over extremely short intervals of time. He wrote

Inevitably, one came up against fundamental physical limits to the accuracy of measurement. Typically, these limits seemed to be related in a complementary way, so that one of them could be widened only at the expense of a narrowing of another. An increase in time-resolving power, for example, seemed always to be bought at the expense of a reduction in frequency-resolving power; an improvement in signal-to-noise ratio was often inseparable from a reduction in time-resolving power, and so on. The art of physical measurement seemed to be ultimately a matter of compromise, of choosing between reciprocally related uncertainties.

I was struck by a possible analogy between this situation and the one in atomic physics expressed by Heisenberg's well-known 'Principle of Uncertainty'. This states that the momentum (p) and position (q ) of a particle can never be exactly determined at the same instant. The smaller the imprecision (Δp) in p, the larger must be the imprecision (Δq ) in q and vice versa. In fact, the product ΔpΔq can never be less than Planck's Constant h, the 'quantum of action'. Action (energy x time) is thus the fundamental physical quantity whose 'atomicity' underlies the compromise- relation expressed in Heisenberg's Principle.

MacKay learned a few years later that Dennis Gabor derived a similar relation in 1946. He published a classic paper entitled 'Theory of Communication', in which the Fourier transform theory used in wave mechanics was applied to the frequency-time (f-t) domain of the communication engineer, with the suggestion that a signal occupying an elementary area of Δf Δt = 1/2 could be regarded as a "unit of information", which he called a "logon".

Much earlier, in 1935, the statistician R. A. Fisher had proposed a measure of the "information' in a statistical sample, which in the simplest case amounted to the reciprocal of the variance.

MacKay was not sure how Gabor's and Fisher's concepts fitted into the theory of information, but

on reflection it became apparent that they were in fact examples of ' structural' and ' metrical' measures, respectively. Gabor's logons, each occupying an area Δf Δt = 1/2 in the f - t plane, represented the logical dimensions of his communication signals. They belonged to the same family as the ' structural units' that occupy an analogous elementary area (the Airy disc) in the focal plane of a microscope, or of a radar aerial. It thus seemed appropriate, with Gabor's blessing, to give the term 'logon-content' a more general definition, as the measure of the logical dimensionality of representations of any form, whether spatial or temporal.

Fisher's measure, which is additive for averaged samples, invited an equally straightforward interpretation as an index of 'weight of evidence'. If we define (arbitrarily but reasonably) a unit or quantum of metrical information (termed a 'metron') as the weight of evidence that gives a probability of \ to the corresponding proposition, Fisher's 'amount of information' becomes simply proportional to the number of such units supplied by the evidence in question

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