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 Tom Clark 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 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 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 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 Werner Loewenstein Hendrik Lorentz Josef Loschmidt Alfred Lotka 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 A.A. Roback Emil Roduner Juan Roederer Jerome Rothstein David Ruelle David Rumelhart 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 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 C. S. Unnikrishnan Francisco Varela Vlatko Vedral Vladimir Vernadsky Mikhail Volkenstein Heinz von Foerster Richard von Mises John von Neumann Jakob von Uexküll C. H. Waddington John B. Watson Daniel Wegner Steven Weinberg Paul A. Weiss Herman Weyl John Wheeler Jeffrey Wicken 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 |
Henry Margenau
Henry Margenau was contributing to the problem of "Probability and Causality in Quantum Physics" in the philosophical journal Monist as a fresh Ph.D. from Yale University in the early 1930's (Monist, 42, 1932, p.161).
In 1937, Margenau wrote a seminal article on quantum theory, entitled "Critical Points in Modern Physical Theory" (Philosophy of Science, Vol. 4, No. 3 (Jul., 1937), pp. 337-370)
This work was cited by Pascual Jordan a dozen years later at a symposium organized by Margenau. Margenau pointed to significant agreement with regard to the central axioms of quantum theory, and that "the ambiguities affect only their philosophical interpretation, a field in which differences of opinion may at present be honestly entertained." He notes that quantum theory establishes a "one-one correspondence, not between states and observed properties, but between states and probability distributions of observed properties." Margenau says that this makes quantum theory a "non-causal" theory. "If causality were to be defined as residing in a unique transition between state and observation, then the description to which this axiom gives rise would have to be termed non-causal." But it is statistically causal and in macroscopic cases there is an "adequate" determinism. Margenau distinguished between what he termed the "objective" (ontological) view and the "subjective" (epistemological) view of quantum mechanics, associating the latter with much talk by Neils Bohr and Werner Heisenberg about the observer and the observer's knowledge. Bohr and Heisenberg mention frequently the conflict between observer and observed object with their unavoidable interaction and thereby presumably express themselves in favor of an objective world, the properties of which are to be described according to the first [objective] view. But this last diagnosis may be in error... In common language, which after the foregoing orienting excursions may perhaps be used without fear of misinterpretation, the distinction in question is simply that between physical objects and the observer's knowledge about physical objects. In classical mechanics the distinction was extremely sharp, and it was supposed that the two, besides being generically different as logical entities, were independent even in a physical sense. States clearly referred to the objects themselves, positions and momenta were their direct properties. The objectivity of states had its culminating expression in the equations of motion, which were understood to imply actual space-time propagation of systems. This propagation took place according to rigid laws independently of the observer's knowledge. Such an extreme view regarding the independent objectivity of physical states cannot be carried over into quantum mechanics; there must at least be a shift of emphasis. One of the great discoveries at the beginning of the present era in physics was the recognition that objects and knowledge are related, because the classical notion of ideally unlimited accuracy of experimental devices failed and made classical knowledge intrinsically impossible. Hence if the view of objectivity be adopted, its classical meaning must be modified to this extent. It goes without saying that states must also be stripped of all impediments pertaining to sensual perception, and thought of entirely in abstracto. Psychological objections to this procedure, frequently raised by members of the older school, are of no particular moment in this connection, for it is not a matter of convenience, but one of logic which concerns us here. The objective view of quantum mechanical states is enormously strengthened by the fact that states develop in time according to a definite differential equation (Schr6dinger's) which has a form not unlike the equations of motion in classical physics. It is true that the simple interpretation of spatio-temporal propagation presents its difficulties or is at any rate no longer intuitively direct, but the fact remains that there are determinate changes in time which are difficult to correlate with simultaneous changes in the observer's knowledge because they seem enforced dynamically and not psychologically. There are further points which may be cited as evidence for the plausibility of the objective view. We have seen (third axiom) that quantum mechanics makes very drastic positive predictions about possible experience, predictions which do not resemble laws of thought and give an impression of utter independence of human knowledge. To be sure this axiom has little to do with the new formalism concerns itself with matters that are thoroughly factual in a sense distinct from mere knowledge. And if this is true there seems to be little motive for insisting that another concept, that of state, should deal not with factual objects but with our modes of awareness. It was pointed out that classical mechanics in all its structure suggests the objective view. Now it is possible to show that, if applied to large scale bodies, quantum mechanics leads to the same physical consequences as does the classical theory. The latter may be said to be the analytical continuation of the former in the field of ordinary experience. This is felt to be a very happy circumstance which bespeaks the unity of physics and encourages the hope that some day a universal theory may be achieved, a hope which at present animates the researches of Einstein. In view of the analytical smoothness with which the two disciplines join it might seem unwise to maintain in one a fundamental attitude which has no place in the other and which would constitute a conceptual break at the passage from one to the other. This argument, too, would suggest an adoption of the objective view. But it should be observed that the points here presented can aim at no more than plausibility, and do not render the opposite view basically untenable. The opposite view, to be called for brevity the subjective view, is the one which holds that state functions describe our knowledge of physical systems. It is psychologically motivated by the significant observation that the independence of classical states is a fallacy. It springs from the desire of making a clean break with erroneous notions and therefore emphasizes an opposite extreme. Let us first see what can possibly be meant by it. Obviously it can not mean that the state function describes the observer's awareness, his momentary state of mind, and the changes in it which occur in time. It is clear that all this depends on factors far removed from the field of physics. Quantum mechanics certainly does not have the aim of converting physics into a highly expressionistict ype of psychology. Although proponentso f this view often employ ambiguous language, what they wish their states to represent is not actual knowledge but potential knowledge. The state function is to be regarded as a convenient carrier, a symbol for the sum total of all that knowledge which the speculative observer can possibly accumulate, at any instant, with the use of all his resources. It may coincide with that knowledge at certain moments of very acute awareness, that is, when the investigator has made all possible measurements and all calculations pertaining thereto. No one can deny that this view, even in its extreme, has in it a trace of objectivism because of the admission that states refer to potential and not to actual knowledge, and this is a feature which makes it slightly inconvenient to have to defend the subjective position; it demands constant vigilance lest an inadvertant lapse should contradict the initial tenet. The chief virtue of the standpoint under discussion is that it provides complete safety against positivistic attacks. Its tenant can justly pride himself in being under no obligation to transcendental agencies for transmitting his knowledge, for he deals with nothing but knowledge which he may believe if he wishes to be generated within his mind. He may wonder perhaps why the laws which govern the evolution of potential knowledge operate with almost dynamic regularity, but this is after all no greater a miracle than the existence of rigid laws in an objective world. The author has not succeeded in bringing to light any further merits of the latter, subjective view. While admitting its possibility on logical grounds, he wishes to record his preference for the former. This preference is partly based on reasons so far presented, partly on considerations of the meaning of probability peculiar to the two attitudes which will now be discussed. The contrast between objectivity and subjectivity of states has an interesting analogue in the theory of probability,6 which, as the reader very likely recalls, can be formulated either as an empirical frequency theory or as a subjective ("a priori") discipline. In the former case, probability is defined as the limit, with increasing number of trials, of the relative frequencies of an occurrence. 8 Probability can be ascertained only empirically, by con-In 1949, Margenau organized a symposium on fundamental questions in quantum theory. The following questions were sent to each of the invited contributors of the symposium: la) What is a physical system, and what is meant by the state of a physical system in classical physics and in quantum mechanics? lb) What philosophical clarification in the concept of a state has resulted from quantum theory? 2a) What is the status of particles in quantum mechanics? 2b) What philosophical changes of the particle concept, and in the concept of mechanism, have resulted from the quantum theory? 3a) In what ways has "causal explanation" been modified by modern quantum theory? 3b) How do these changes affect the philosophic problem of determinism?Pascual Jordan wrote perhaps the most important response to Margenau's questions in his essay "On the process of measurement in quantum mechanics," (Philosophy of Science, 16, 1949, pp. 269-278 (PDF)
Margenau was a close colleague, perhaps more a disciple, of the philosopher Ernst Cassirer and generally claimed to agree with Cassirer's thoughts on causality and determinism. When Cassirer died, Margenau was preparing an appendix for the 1956 English translation of Determinism and Indeterminism in Modern Physics. The appendix was to bring the question of causality up to date as of 1956.
A dozen years later, Margenau was invited to give the Wimmer Lecture at St. Vincent College in Pennsylvania. His topic was Scientific Indeterminism and Human Freedom, and instead of holding to Cassirer's view "that it would be fatal for ethics to tie itself to and, as it were, fling itself into the arms of a limitless indeterminism," Margenau embraced indeterminism as the first step toward a solution of the problem of human freedom.
Margenau lamented that "it forces us to part company with many distinguished moral philosophers who see the autonomy of ethics threatened when a relation of any sort is assumed to exist between that august discipline and science." He clearly means his longtime mentor. "Ethics, says Cassirer, should not be forced to build its nests in the gaps of physical causation, but he fails to tell where else it should build them, if at all." (p.71)
In 1982, with co-author Lawrence LeShan, called his model of free will a "solution" to what had heretofore had been seen as mere "paradox and illusion."
No one will deny that an interaction between mind and body takes place whenever we consciously perform a movement. We now make the additional affirmation that our will — the core of consciousness, wherein the self proclaims its being most emphatically — interacts with the body in a special way when it makes a decision and deliberately activates the body. In pre-quantum days, when philosophy was dominated by Laplacian determinism, in which a state classically defined without recourse to probabilities rigorously entailed all future states (of an isolated system), free will was a paradox and an illusion. That is to say, either it could not be explained, despite the immediate, empirically accurate evidence that affirmed it, or its affirmation was false. This situation has changed by virtue of the discovery of quantum mechanics. The new discipline provides. the possibility of a solution by removing the impediment of old-style determinism. Our thesis is that quantum mechanics leaves our body, our brain, at any moment in a state with numerous (because of its complexity we might say innumerable) possible futures, each with a predetermined probability. Freedom involves two components: chance (existence of a genuine set of alternatives) and choice. Quantum mechanics provides the chance, and we shall argue that only the mind can make the choice by selecting (not energetically enforcing) among the possible future courses. For Teachers
For Scholars
Human Freedom (section 5 from) Scientific Indeterminism and Human Freedom, Wimmer Lecture XX, 1968
In the first three sections of this lecture I have sketched the determinism of classical physics and the indeterminism of present science. The latter was not recognized until the present century. The problem of freedom, however, has been with us since the dawn of philosophy, and it behooves us now to follow up the allusions at the beginning of section 1 and comment on the uneasy union between deterministic science and freedom-conscious moral philosophy which existed throughout the centuries that preceded ours. A systematic review of all the devices whereby philosophers have tried to harmonize causality and freedom is impossible here. A sketch of three of them must suffice. One, which has the authority of Spinoza and some modern theologians, invokes a distinction between inward and outward experiences. Freedom is a phenomenon of consciousness of which one becomes aware by introspection. Determinism regulates processes from without. A stone in flight, said Spinoza, if it were awakened to consciousness, would deem itself free to move along its predetermined path; it would feel it had chosen its trajectory. The difference between determinism and freedom has been likened to two seemingly contradictory properties of physical objects: The windshield of a car is concave when seen from the inside, convex from the outside. This explanation, in spite of its allegorical appeal, nevertheless leaves freedom in an unsatisfactory state, for when all is said and done it remains a psychological illusion. Next is a thesis which accounts for freedom by an appeal to ignorance. An omniscient being is not free, since knowing what happens excludes all choice in situations which otherwise permit it. The example sometimes cited is that of a child which is given a choice between a dish of spinach and a piece of pie. His mother, knowing that he dislikes spinach, knows the outcome, concludes therefore that he has no choice, while the child believes he is facing a genuine alternative. It is the limitation of his knowledge about himself which gives him the sense of being free. Again, it is difficult to see how this kind of reasoning explains any more than one's feeling of freedom, not its actual existence. Last is a view which is found in the writings of Kant and developed in detail to fit modern science by Cassirer. Their philosophy, called transcendental idealism, regards causality as a category of human understanding, a necessary form in which all knowledge of events must be cast. For things in themselves, which lie beyond our comprehension, causality and all other basic modes of thought are irrelevant. This is what is meant by calling causality a transcendental principle of understanding. From this point of view universal causality or determinism, whether of the classical or the quantum mechanical sort, must not be regarded as a metaphysical constraint upon all forms of being. It must be distinguished from what Cassirer calls a "dinglicher Zwang". Freedom, too, is a transcendental principle, but one regulating our actions, and it therefore controls another realm. If both were factual, descriptive attributes of the world they would indeed collide; only their transcendental nature keeps them out of conflict and makes them compatible. Now it seems to me that classical determinism and freedom do collide — in a factual sense if both are taken as ultimate metaphysical principles, and in the form of logical irreconcilables if they are transcendental modes of explanation which regulate our understanding. Let me illustrate the meaning of this claim by reference to a trivial example (which has no ethical significance, to be sure). Suppose I am asked to raise my hand, I can do this mechanically without thought and without engaging my will. In that case, habit acquired during my student days will probably cause me to raise my right hand. One may look upon this action as a causal one, whose result is predictable in terms of conditions existing in my brain, of associations acquired, of neural pathways previously established, and so on. But notice: I took care to say that I would probably raise my right hand, thereby implying something less than strict predictability. But if I am told: raise which ever hand you wish, the sequence of events is different. I am somehow challenged to think and then to make a choice. To believe that, during the moment of reflection preceding the decision to raise my left hand, the configuration of the molecules in my body, the currents in my brain cells, or even the psychological variables composing my mental state have already predetermined that I must raise my left hand is clearly false, for it contradicts the most elementary, the most reliable, self-declarative awareness of choice which accompanies this act. Thus a serious contradiction arises if strict causality is a metaphysical fact. Nor can the situation be saved by saying, with Kant and Cassirer, that causality is merely a transcendental principle in terms of which we are required to conceive things. For in that case we should require one principle of understanding to comprehend the sequence of events which compose the objective course leading to the raising of my left hand, and a different, incompatible one to explain my feeling of freedom. Human reason does not tolerate two incoherent principles where a single one will do. I shall now show that the loosening of causality required by quantum mechanics enlarges the scope of that principle sufficiently to allow removal of these difficulties and to cover both determination and freedom. What I hope to accomplish needs careful statement. It might seem to be a proof that quantum mechanics has solved the problem of freedom. This is a vastly different task from showing that quantum mechanics has removed an essential obstacle from the road toward its solution, while the problem remains unsolved in its major details. The following analysis is directed toward this latter, much more modest aim. In approaching it, however, many of the difficulties, whose resolution constitutes the difference between the first and second tasks, will move into view. The decision which hand to raise is totally without ethical relevance; it merely illustrates the contrast between instinctive-reflexive, almost mechanical behavior and an action which involves thought and will, thereby engaging to a small extent the quality of freedom. The question of motivation, so essential in ethics, hardly enters at all. Or if it does, if for some conscious reason — perhaps the desire to surprise my partner — I have chosen to lift my left arm when he expected the right one to be raised, that reason is far from the concerns of ethics. The distance from here to choices which can be said to be morally good or bad, which conform or do not conform to ethical principles, which carry responsibility, is very great. Yet somehow it can be travelled by vehicles already at our disposal.
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