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 BoisReymond 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.NowellSmith 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 JeanPaul Sartre Kenneth Sayre T.M.Scanlon Moritz Schlick Arthur Schopenhauer John Searle Wilfrid Sellars Alan Sidelle Ted Sider Henry Sidgwick Walter SinnottArmstrong 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 JeanPierre 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 JohnDylan 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 PierreSimon 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 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 
The Quantum to Classical Transition
There is only one world.
Information physics claims there is only one world, the quantum world, and that the appearance of a "quantum to classical transition" occurs for any large macroscopic object that contains a large number of atoms. For large enough systems, independent quantum events are "averaged over." The uncertainty in position and momentum of the object (Δv Δx > h / m) becomes less than observational accuracy as m gets large and h / m goes to zero.
It is a quantum world. Ontologically it is indeterministic, but epistemically, our common sense and experience with large objects inclines us to see the world as deterministic Note that macroscopic objects are quantum objects. But the uncertainty in their position and momentum is not detectable by our measuring instruments. The classical laws of motion appear to apply perfectly to macroscopic objects, because quantum effects can be neglected.
Bohr called the discontinuous (and indeterministic) "quantum jumps" in his model for the atom the "quantum postulate."
Niels Bohr correctly insisted that classical physics plays an essential role in quantum mechanics. His Correspondence Principle allowed him to recover some important physical constants by assuming that the discontinuous quantum jumps for low quantum numbers (low "orbits" in his old quantum theory model) converged in the limit of large quantum numbers to the continuous radiation emission and absorption of classical electromagnetic theory.
We know that in macroscopic bodies with enormous numbers of quantum particles, quantum effects are averaged over. So that although the uncertainty in position and momentum of a large body still obeys Heisenberg's indeterminacy principle, the uncertainty is for all practical purposes unmeasurable and the body can be treated classically. We can say that the quantum description of matter also converges to a classical description in the limit of large numbers of quantum particles. We call this "adequate" or statistical determinism. It is the apparent determinism we find behind Newton's laws of motion for macroscopic objects. The statistics of averaging over many independent quantum events then produces the "quantum to classical transition" for the same reason as the "law of large numbers" results in the "central limit theorem" in probability theory. Both Bohr and Heisenberg suggested that just as relativistic effects can be ignored when the velocity is small compared to the velocity of light (v / c → 0), so quantum effects might be ignorable when Planck's quantum of action h → 0. But this is quite wrong, because h is a constant that never goes to zero. In the information interpretation, it is always a quantum world. The correct conditions needed for ignoring quantum indeterminacy are when the mass of the macroscopic "classical" object is large. Noting that the momentum p is the product of mass and velocity mv, Heisenberg's indeterminacy principle, Δp Δx > h, can be rewritten as Δv Δx > h / m. It is thus not when h is small, but when h / m is small enough, that errors in the position and momentum of macroscopic objects become smaller that can be measured. The quantum to classical transition is then when h / m becomes small. A similar limit can be seen by analogy with optics. When the wavelength of light is large compared to the dimensions of the system, wave optics must be used and diffraction effects become important. On the other hand, when the wavelength of light is small compared to the apertures in the optical system, geometrical optics is applicable (ray tracing). Similarly, classical mechanics is applicable when the de Broglie wavelength λ = h / p is small compared to the dimensions of the experimental measurement apparatus. Once again, the quantum to classical transition is when h / p = h / mv becomes small.
Note that the macromolecules of biology are large enough to stabilize their information structures. DNA has been replicating its essential information for billions of years, resisting equilibrium and keeping its entropy very low despite the second law of thermodynamics
The creation of irreversible new information also marks the transition between the quantum world and the "adequately deterministic" classical world, because the information structure itself must be large enough (and stable enough) to be seen. The typical measurement apparatus is macroscopic, so the quantum of action h becomes small compared to the mass m and h / m approaches zero.
Decoherence Theory and the Quantum to Classical Transition
Decoherence theorists say that the quantumtoclassical transition occurs because of interactions with the environment, for example everpresent thermal photons. The cosmic microwave background is a constant source of lowenergy photons. Without specifying the mechanics of the interaction between the photons and the quantum system being described, the decoherence theorists say that the photons cause the "selection" of preferred pointer positions, for example, the eigenvalues of the combined target quantum system and the measurement apparatus. They call this "einselection," a word coined from "environmentally induced superselection."
Decoherence theorists say einselection explains the appearance of wave function collapse (they deny actual collapses) and the emergence of classical descriptions of reality from quantum descriptions. Information physics agrees that classicality is an emergent property, but it is not induced in open quantum systems by their environments. Macroscopic quantum objects, with h / m so small that the uncertainty Δp Δx > h is undetectable, appear classical in both open and closed environments. Unlike information physics, which identifies exactly how radiation interactions with matter (the emission, absorption, and scattering of photons) erase path information about correlations between the molecules of a gas, thus proving Boltzmann's HTheorem and his assumption of "molecular chaos," decoherence arguments about environmental photons are merely "hand waving."
Decoherence theorists also say that our failure to see quantum superpositions in the macroscopic world is the measurement problem. The information interpretation of quantum mechanics explains clearly why quantum superpositions like Schrödinger's Cat are not seen in the macroscopic world. Stable new information structures in the dying cat reduce the quantum possibilities (and their potential interference effects) to a classical actuality. Just before opening the box, quantum mechanics provides the two possibilities of "live" and "dead" cat, with calculable probabilities. Upon opening the box and finding a dead cat, an autopsy will reveal that the time of death was recorded and in some sense "observed." A human experimenter is not needed to collapse the wave function. The macroscopic cat is its own measuring apparatus and observer. Not only do objects appear to be "classical" when they are large enough, the classical laws of motion, with their implicit determinism and strict causality, emerge when microscopic events can be ignored, but this determinism is fundamentally statistical. Information philosophy interprets the wave function ψ as a "possibilities" function. With this simple change in terminology, the mysterious process of a wave function "collapsing" becomes a much more intuitive discussion of ψ exploring possibilities (with mathematically calculable probabilities), followed by a single actuality, at which time alternative probabilities go to zero ("collapse") instantaneously.
Information physics is standard quantum physics. It accepts the Schrödinger equation of motion, the principle of superposition, the axiom of measurement (now including the actual information "bits" measured), and  most important  the projection postulate of standard quantum mechanics (the "collapse" that so many interpretations deny). But the conscious observer of the Copenhagen Interpretation is not required for a projection, for the wavefunction to "collapse", for one of the possibilities to become an actuality. What it does require is an interaction between systems that creates irreversible and observable, but not necessarily observed, information. Among the founders of quantum mechanics, almost everyone agreed that irreversibility was a key requirement for a measurement. Irreversibility introduces thermodynamics into a proper formulation of quantum mechanics, and this is what the information interpretation does.
Information is not a conserved quantity like energy and mass, despite the view of many mathematical physicists, who generally accept determinism. The universe began in a state of equilibrium with minimal information, and information is being created every day, despite the second law of thermodynamics
Classical interactions between large macroscopic bodies do not generate new information. Newton's laws of motion imply that the information in any configuration of bodies, motions, and force is enough to know all past and future configurations. Classical mechanics conserves information.
In the absence of interactions, an isolated quantum system evolves according to the unitary Schrödinger equation of motion. Just like classical systems, the deterministic Schrödinger equation conserves information. Unlike classical systems however, when there is an interaction between quantum systems, the two systems become entangled and there may be a change of state in either or both systems. This change of state may create new information.
If that information is instantly destroyed, as in most interactions, it may never be observed macroscopically. If, on the other hand, the information is stabilized for some length of time, it may be seen by an observer and considered to be a "measurement." But it need not be seen by anyone to become new information in the universe. The universe is its own observer!
For the information (negative entropy) to be stabilized, the second law of thermodynamics requires that an amount of positive entropy greater than the negative entropy must be transferred away from the new information structure.
Note that despite the Heisenberg principle, quantum mechanical measurements are not always uncertain. When a system is measured (prepared) in an eigenstate, a subsequent measurement (Pauli's measurement of the first kind) will find it in the same state with perfect certainty.
What then are the possibilities for new quantum states? The transformation theory of Dirac and Jordan lets us represent ψ in a set of basis functions for which the combination of quantum systems (one may be a measurement apparatus) has eigenvalues (the axiom of measurement). We represent ψ as in a linear combination (the principle of superposition) of those "possible" eigenfunctions. Quantum mechanics lets us calculate the probabilities of each of those "possibilities."
Interaction with the measurement apparatus (or indeed interaction with any other system) may select out (the projection postulate) one of those possibilities as an actuality. But for this event to be an "observable" (a John Bell "beable"), information must be created and positive entropy must be transferred away from the new information structure, in accordance with our twostage information creation process.
All interpretations of quantum mechanics predict the same experimental results. Where interpretations differ is in the picture (the visualization) they provide of what is "really" going on in the microscopic world  the socalled "quantum reality." The "orthodox" Copenhagen interpretation of Neils Bohr and Werner Heisenberg discourages such attempts to understand the nature of the "quantum world," because they say that all our experience is derived from the "classical world" and should be described in ordinary language. This is why Bohr and Heisenberg insisted on the path and the "cut" between the quantum event and the mind of an observer. The information interpretation encourages visualization. Schrödinger called it Anschaulichkeit. He and Einstein were right that we should be able to picture quantum reality. But that demands that we accept the reality of quantum possibilities and discontinuous random "quantum jumps," something many modern interpretations do not do. (See our visualization of the twoslit experiment, our EPR experiment visualizations, and Dirac's three polarizers to visualize the superposition of states and the projection or "collapse" of a wave function.) Related to the Heisenberg Cut, but really quite different.
Three Examples of a "Classical" Apparatus  the Photographic Plate, a CCD, the cloud chamber.
A macroscopic object with a vast number of quantumscale systems prepared in "metastable" states.
The Decoherence Explanation
Schlosshauer agrees there is only one world  the quantum world. But there is no universal wave function, which is a construction to prevent any new information being created and establish determinism.
Normal  Teacher  Scholar
