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Core Concepts
Abduction Belief Best Explanation Cause Certainty Chance Coherence Correspondence Decoherence Divided Line Downward Causation Emergence Emergent Dualism ERR Identity Theory Infinite Regress Information Intension/Extension Intersubjectivism Justification Materialism Meaning Mental Causation Multiple Realizability Naturalism Necessity Possible Worlds Postmodernism Probability Realism Reductionism Schrödinger's Cat Supervenience Truth Universals Topics Introduction Problems Freedom Knowledge Mind Life Chance Quantum Entanglement Scandals 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 Susan Blackmore Susanne Bobzien Emil du Bois-Reymond Hilary Bok Laurence BonJour George Boole Émile Boutroux Daniel Boyd F.H.Bradley C.D.Broad Michael Burke Jeremy Butterfield Lawrence Cahoone C.A.Campbell Joseph Keim Campbell Rudolf Carnap Carneades Nancy Cartwright Gregg Caruso Ernst Cassirer David Chalmers Roderick Chisholm Chrysippus Cicero Tom Clark Randolph Clarke Samuel Clarke Anthony Collins August Compte Antonella Corradini Diodorus Cronus Jonathan Dancy Donald Davidson Mario De Caro Democritus Daniel Dennett Jacques Derrida René Descartes Richard Double Fred Dretske Curt Ducasse 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 Niels Henrik Gregersen 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 James Ladyman 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 Ernest Nagel 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 U.T.Place 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 John Duns Scotus Albert Schweitzer Arthur Schopenhauer John Searle Wilfrid Sellars David Shiang Alan Sidelle Ted Sider Henry Sidgwick Walter Sinnott-Armstrong Peter Slezak 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 Xenophon Scientists David Albert Philip W. Anderson Michael Arbib Walter Baade Bernard Baars Jeffrey Bada Leslie Ballentine Marcello Barbieri Jacob Barandes Julian Barbour Horace Barlow Gregory Bateson John S. Bell Mara Beller Charles Bennett Ludwig von Bertalanffy Susan Blackmore Margaret Boden David Bohm Niels Bohr Ludwig Boltzmann John Tyler Bonner Emile Borel Max Born Satyendra Nath Bose Walther Bothe Jean Bricmont Hans Briegel Leon Brillouin Daniel Brooks Stephen Brush Henry Thomas Buckle S. H. Burbury Melvin Calvin William Calvin Donald Campbell John O. Campbell Sadi Carnot Anthony Cashmore Eric Chaisson Gregory Chaitin Jean-Pierre Changeux Rudolf Clausius Arthur Holly Compton John Conway Simon Conway-Morris Peter Corning George Cowan Jerry Coyne John Cramer Francis Crick E. P. Culverwell Antonio Damasio Olivier Darrigol Charles Darwin Paul Davies Richard Dawkins Terrence Deacon Lüder Deecke Richard Dedekind Louis de Broglie Stanislas Dehaene Max Delbrück Abraham de Moivre David Depew Bernard d'Espagnat Paul Dirac Theodosius Dobzhansky Hans Driesch John Dupré John Eccles Arthur Stanley Eddington Gerald Edelman Paul Ehrenfest Manfred Eigen Albert Einstein George F. R. Ellis Walter Elsasser Hugh Everett, III Franz Exner Richard Feynman R. A. Fisher David Foster Joseph Fourier George Fox Philipp Frank Steven Frautschi Edward Fredkin Augustin-Jean Fresnel Karl Friston 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 Ernst Haeckel 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 Hermann von Helmholtz Grete Hermann John Herschel Basil Hiley Art Hobson Jesper Hoffmeyer Don Howard John H. Jackson Ray Jackendoff Roman Jakobson E. T. Jaynes William Stanley Jevons 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 Bernd-Olaf Küppers Rolf Landauer Alfred Landé Pierre-Simon Laplace Karl Lashley David Layzer Joseph LeDoux Gerald Lettvin Michael Levin Gilbert Lewis Benjamin Libet David Lindley Seth Lloyd Werner Loewenstein Hendrik Lorentz Josef Loschmidt Alfred Lotka Ernst Mach Donald MacKay Henry Margenau Lynn Margulis Owen Maroney David Marr Humberto Maturana James Clerk Maxwell John Maynard Smith Ernst Mayr John McCarthy Barabara McClintock Warren McCulloch N. David Mermin George Miller Stanley Miller Ulrich Mohrhoff Jacques Monod Vernon Mountcastle Emmy Noether Donald Norman Travis Norsen Howard T. Odum 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 Michael Polanyi Daniel Pollen Ilya Prigogine Hans Primas Zenon Pylyshyn Henry Quastler Adolphe Quételet Pasco Rakic Nicolas Rashevsky Lord Rayleigh Frederick Reif Jürgen Renn Giacomo Rizzolati A.A. Roback Emil Roduner Juan Roederer Robert Rosen Frank Rosenblatt Jerome Rothstein David Ruelle David Rumelhart Stanley Salthe Robert Sapolsky Tilman Sauer Ferdinand de Saussure Jürgen Schmidhuber Erwin Schrödinger Aaron Schurger Sebastian Seung Thomas Sebeok Franco Selleri Claude Shannon Charles Sherrington Abner Shimony Herbert Simon Dean Keith Simonton Edmund Sinnott B. F. Skinner Lee Smolin Ray Solomonoff Herbert Spencer Roger Sperry John Stachel Kenneth Stanley Henry Stapp Ian Stewart Tom Stonier Antoine Suarez Leonard Susskind Leo Szilard Max Tegmark Teilhard de Chardin Libb Thims William Thomson (Kelvin) Richard Tolman Giulio Tononi Peter Tse Alan Turing Robert Ulanowicz C. S. Unnikrishnan Nico van Kampen Francisco Varela Vlatko Vedral Vladimir Vernadsky Clément Vidal Mikhail Volkenstein Heinz von Foerster Richard von Mises John von Neumann Jakob von Uexküll C. H. Waddington Sara Imari Walker James D. Watson John B. Watson Daniel Wegner Steven Weinberg August Weismann Paul A. Weiss Herman Weyl John Wheeler Jeffrey Wicken Wilhelm Wien Norbert Wiener Eugene Wigner E. O. Wiley E. O. Wilson Günther Witzany Carl Woese Stephen Wolfram H. Dieter Zeh Semir Zeki Ernst Zermelo Wojciech Zurek Konrad Zuse Fritz Zwicky Presentations Biosemiotics Free Will Mental Causation James Symposium CCS25 Talk Evo Devo September 12 Evo Devo October 2 Evo Devo Goodness |
History of Complexity Theory
My search for the origin of complexity and complex systems has taken me back to Herbert Spencer's 1857 essay, "Progress: Its Law and Cause." This essay later formed the basis of his 1862 book First Principles of a New System of Philosophy. In it Spencer expounded a theory of evolution which posits that all structures in the universe develop from a simple, undifferentiated, homogeneity to a complex, differentiated, heterogeneity while undergoing increasing integration of the differentiated parts. This evolutionary process can be observed, Spencer believed, throughout the cosmos. It is a universal law, applying to biological organisms, to human social organisation, and to the human mind.
The Oxford English Dictionary does not cite Spencer, but one of its earliest citations is Charles Darwin's 1859 Life and Letters, vII, p.219, where he writes "A tendency to advance in complexity of organization." It's very likely that Darwin's usage followed Spencer's, so from the beginning complexity was a key, perhaps a defining, attribute of living things.
In Herbert Simon's 1969 book The Sciences of the Artificial, he referenced his 1962 essay The Architecture of Complexity, where he traces the history back to the idea of a general systems theory, like that of Ludwig von Bertalanffy. Simon writes...
A NUMBER of proposals have been advanced in recent years for the development of "general systems theory" which, abstracting from properties peculiar to physical, biological, or social systems, would be applicable to all of them. We might well feel that, while the goal is laudable, systems of such diverse kinds could hardly be expected to have any nontrivial properties in common. Metaphor and analogy can be helpful, or they can be misleading. All depends on whether the similarities the metaphor captures are significant or superficial. It may not be entirely vain, however, to search for common properties among diverse kinds of complex systems. The ideas that go by the name of cybernetics constitute, if not a theory, at least a point of view that has been proving fruitful over a wide range of application. It has been useful to look at the behavior of adaptive systems in terms of the concepts of feedback and homeostasis, and to analyze adaptiveness in terms of the theory of selective information. The ideas of feedback and information provide a frame of reference for viewing a wide range of situations, just as do the ideas of evolution, of relativism, of axiomatic method, and of operationalism. In this paper I should like to report on some things we have been learning about particular kinds of complex systems encountered in the behavioral sciences.In 1977 the Belgian physical chemist Ilya Prigogine won the Nobel prize for investigating the irreversibility of processes in complex physical systems far from equilibrium conditions. These are physical or chemical systems far from equilibrium conditions that appear to develop "order out of chaos" and look to be "self-organizing." Like biological systems, matter and energy (of low entropy) flows through the "dissipative" structure. It is primarily free energy and negative entropy that is being "dissipated." This similarity to biological systems (in just one very important thermodynamic respect) was exploited by Prigogine to say he had discovered "new laws of nature" that could connect the natural sciences to the human sciences. Dissipation also implies irreversibility, a very important characteristic of life. Prigogine had no physical explanation for irreversibility - beyond the fact that his physical "dissipative structures" and biological systems - exhibited it. He generally attacked classical Newtonian dynamics as being time reversible and thus providing no understanding of time. His understanding of time was based on the work of Henri Bergson and the uneven flow of time Bergson called "duration." The Nobel committee wrote... The great contribution of Prigogine to thermodynamic theory in his successful extension of it to systems which are far from thermodynamic equilibrium. This is extremely interesting as large differences compared to conditions close to equilibrium had to be expected. Prigogine has demonstrated that a new form of ordered structures can exist under such conditions, and he has given them the name ''dissipative structures" to stress that they only exist in conjunction with their environment.Prigogine is perhaps the most famous name in chaos theory and complexity theory. Although he made very few original contributions to these fields, he is famous for them, nevertheless. His work (especially his 1984 book written with Isabel Stengers, Order Out Of Chaos) is a major reference today for popular concepts like "self-organizing, "complex systems," "bifurcation points," "non-linearity,", "attractors," "symmetry breaking," "morphogenesis," "autocatalytic," "constraint," and of course "irreversibility," although none of these terms is originally Prigogine's. The name "dissipative structures" and perhaps the phrase "far from equilibrium" belong to Prigogine, but the thermodynamic concepts were already in Boltzmann, Bertalanffy, and Schrödinger, and perhaps many others. In 1984 the Santa Fe Institute was founded by Los Alamos scientists George A Cowan, Murray Gell-Mann, and others. See this history. Cowan also recounts the history in his 2010 book Manhattan Project to the Santa Fe Institute and this hour-long video interview The Santa Fe Institute became famous for their studies of complexity and complex systems. Their mission is "Searching for Order in the Complexity of Evolving Worlds" and they write... In 1989, a 5-day workshop on Complexity, Entropy, and the Physics of Information was attended by over 40 of the world's top scientists in those subjects (a key exception was Prigogine).. They published a manifesto in 1990...
COMPLEXITY, ENTROPY, AND THE PHYSICS OF
INFORMATION - A MANIFESTO
■ A deep analogy between thermodynamic entropy and Shannon's infornation
theoretic entropy. Since the introduction of Maxwell's Demon and, partiularly,
since the celebrated paper of Szilard and even earlier discussions of Smolu
chowski, the operation equivalence of the gain of information and the decrease
of entropy has been widely appreciated. Yet, the notion that a subjective quantity
such as infofmatton could influence "objective" thermodynamic properties
of the system remains highly controversial.
It is, however, difficult to deny that the process of informalion can be
directly tied to the ability to extract useful work. Thus, questions concerning thermodynamics,
the second law, and the arrow of time have become intertwined with
a half-century-old puzzle, that of the problem of measurements in quantum physics.
■ Quantum meanrements are usually analyzed in abstract terms or wave functions and hamiltonians. Only very few discussions of the measurement problem in quantum theory make an explicit effort to consider the crucial issue - the transfer of information. Yet obtaining knowledge is the very reason for making a measurement. Formulating quantum measurements and, more generally, quantum phenomena in terms of information should throw a new light on the problem of measurement, which has become difficult to ignore in light of new experiments on quantum behavior in macroscopic systems.The distinction between what is and what is known to be, so clear in classical physics, is blurred, and perhaps does not exist at all on a quantum level. For instance, energetically insignificant interactions of an object with its quantum environment suffice to destroy its quantum nature. It is as if the "watchful eye" of the environment "monitoring" the state of the quantum system forced it to behave in an effectively classical manner. Yet, even phenomena involving gravity, which happen on the most macroscopic of all the scales, bear the imprint of quantum mechanics. ■ Black hole thermodynamics has established a deep and still largely mysterious connection between general relativity, quantum, and statistical mechanics. Related questions about the information capacity of physical systems, fundamental limits on the capacity of communication channels, the origin of entropy in the Universe, etc., are a subject of much recent research. The three subjects above lie largely in the domain of physics. The following issues forge connections between the natural sciences and the science of computation, or, rather, the subject of information processing regarded in the broadest sense of the word. ■ Physics of computation explores limitations imposed by the laws of physics on the processing of information. It is now established that both classical and quantum systems can be used to perform computations reversibly. That is, computation can be "undone" by running the computer backwards. It appears also conceivable that approximately reversible computer "chips" can be realized in practice. These results are of fundamental importance, as they demonstrate that, at least in principle, processing of information can be accomplished at no thermodynamic cost. Moreover, such considerations lead one to recognize that it is actually the erasure of the information which results in the increase of entropy.The information which is being processed by the computer is a concrete "record," a definite sequence of symbols. Its information content cannot be represented adequately in terms of Shannon's probabilistic definition of information. One must instead quantify the information content of the specific, well-known "record" in the memory of the computer - and not its probability or frequency of occurrence, as Shannon's formalism would demand. Fortunately, a relatively new developmenta novel formulation of the information theory - has been already put forward. ■ Algorithmic randomness - an alternative definition of the information content of an object based on the theory of computation rather than on probabilities was introduced more then two decades ago by Solomonof. Kolmogorov, and Chaitin. It is equal to the size of the shortest message which describes this object. For instance, a string of 105 0's and 1 's:It is tempting to suggest that physical entropy - the quantity which determines how much work can be extracted from a physical system - should take into account its algorithmic randomness. This suggestion can be substantiated by detailed discussions of examples of computer-operated engines as well as by results concerning the evolution of entropy and algorithmic randomness in the course of measurements. It provides a direct link between thermodynamics, measurements, and the theory of computation. Moreover, it is relevant to the definition of complexity. ■ Complerity, its meaning, its measures, its relation to entropy and information, and its role in physical, biological, computational, and other contexts have become an object of active research in the past few years. |