Presentation Transcript

1. The Copernican Revolution

   How we all became materialists!
2. Aristotle’s World as formulated by Ptolemy - Man is rightfully at its centre.The earth is clearly: solid, immovable, enormous. Its natural physics is clearly that natural motion is variable and vertically towards or away from its centre. The celestial sphere is light, diaphanous, tiny, nearby.Its natural physics is clearly that natural motion is circular and uniform
3. The Copernican Problem1473-1543 The earth is no longer unique but just another planet. Via trigonometry the scale of the solar system can be approximated. It is immensely vast. Earth’s orbit = 160,000,000 km ,Circumference 1,000,000,000 km, speed 30 km/sec. No stellar parallax. The distant stars must be unimaginably far. The universe becomes large beyond comprehension. Man is reduced in scale and importance dramatically. Explain that! Who has mankind become in such a vast and impersonal universe? No physics to explain the observed phenomena on the earth if it moves. No physics to explain the movement of the planets other than the Aristotelian perfect circular motion hypothesis.
4. Galileo gets on the Job1564-1642 “The crucial thing is being able to move the earth without creating a thousand inconveniences.”Simplicius from Galileo’s Dialogue. Motion is not an essence of the body but merely a state in which it finds itself. As Galileo says, the body is “indifferent” to its state of motion or rest.
5. All bodies are indifferent - INERT
6. Newton Finishes the Job.Celestial motion is merely terrestrial rectilinear motion with a gravitational force added.
7. NEWTON 1642-1727 Unified terrestrial and celestial phenomena. Showed both (everything) are simple relations caused by matter, motion and force. All can be explained by Matter and the Void.
8. “Nature, and Nature’s Laws lay hid in Night. God said, Let Newton be! And All was Light.” Alexander Pope 1688-1744
9. Materialism is born. Newton gives physical phenomena independence, detachment, indifference. The world becomes immutable, eternal, aloof, heartless. Newton’s world is without TELEOLOGY. It is merely physical entities and processes eternally operating on each other according to simple mathematical laws. It does not require God to function and go about its business. It is a mechanism made up of atoms interacting under Newton’s Laws operating within the vast voids of absolute time and space. Descartes is all that stands between the Western mind and the mechanistic world of material determinism.
10. John Donne 1572-1631 “And new Philosophy calls all in doubt, The element of fire is quite put out; The Sun is lost, and th’ earth, and no mans wit Can well direct him where to looke for it. And freely men confess that this world’s spent When in the Planets, and the Firmament They seeke so many new; then see that this Is crumbled out againe to his Atomies. ‘Tis all in peeces, all cohaerrence gone; All just supply, and all Relation.” John Donne
11. Thomas Hobbes1588-1679 Thomas Hobbes, an English contemporary of Galileo, understood immediately the profound effect of the Galilean dynamics: “Thus mind will be nothing but the motions of certain parts of an organic Body”
12. Pierre-Simon, Marquis de Laplace “ We may regard the present state of the universe as the effect of its past and the cause of its future. An intellect which at a certain moment would know all forces that set nature in motion, and all positions of all items of which nature is composed, if this intellect were also vast enough to submit these data to analysis, it would embrace in a single formula the movements of the greatest bodies of the universe and those of the tiniest atom; for such an intellect nothing would be uncertain and the future just like the past would be present before its eyes. ” 1749-1827
13. Descartes "Cogito ergo sum”: English: “I think, therefore I am” Mind had been eliminated from the physical world. The human mind remained its last remaining possibility. Cartesian dualism has become the last popular stronghold against materialism and the last remaining battleground for mystery. It concedes the body but remains (increasingly less) hopeful the mind will defy physical analysis.
14. Pythagorean Atomism
15. Various atoms and molecules as depicted in John Dalton's A New System of Chemical Philosophy (1808).
16. Cathode Rays - Electrons J.J. Thomson's illustration of the Crookes tube by which he proved the particle nature of cathode rays (electrons). Cathode rays were emitted from the cathode C, sharpened to a beam by slits A and B, then passed through the electric field generated between plates D and E. (1897)
17. The Gold Foil Experiment J.J. Thompson’s Plum Pudding model of the Atom. (1810) Expected results: alpha particles passing through the plum pudding model of the atom with negligible deflection. Ernest Rutherford’s experiments showed that the plum pudding model of the atom was incorrect and that a solar system model seemed experimentally conclusive. Observed results: a small portion of the particles were deflected by the concentrated positive charge of the nucleus
18. Atomic Theoryfor the Everyday Materialist
19. Periodic Table
20. The Reductionist ProjectAll science is either physics or stamp collecting. Ernest Rutherford.1871-1937 PHYSICS ETHICS SOCIOLOGY PSYCHOLOGY BIOLOGY CHEMISTRY
21. Is there a Ghost in the Machine?
22. “It did not last: the Devil howling ‘Ho, Let Einstein be, ‘ restore the status quo.” J.C. Squire
23. Although it was predictively powerful, Newton never trusted the concept of Gravitation as he believed it was an OCCULT quality.
24. Classical AtomIf we compress all the void out of a human being so that there is only protons, neutrons and electrons in physical contact, the resulting object would only be visible under a microscope.
25. Atomic Reductionism Increasingly sophisticated models of matter have been developed throughout the 20th Century and have become the basis for a very strong realist materialism.
26. Why does it not spiral in and collapse?

27. QUANTUM THEORY

    “Something is happening here but you don’t know what it is, do you Mr Jones” Bob Dylan
28. Waves
29. Interference of waves are commonly observed
30. Wave Interference
31. Thomas Young’s Double Slit Experiment - c. 1801
32. Wave Theory
33. Photoelectric Effect - Wave/Particle Duality and the Quantum is proposed "On a Heuristic Viewpoint Concerning the Production and Transformation of Light” - Einstein c. 1905 h is Planck's constant f is the frequency of the incident photon the minimum energy required to remove a delocalised electron from the surface of any given metal f0 is the threshold frequency for the photoelectric effect to occur, m is the rest mass of the ejected electron, and vm is the velocity of the ejected electron.
34. Light Behaves as both Wave and Particle The remarkable aspects of the photoelectric effect when it was first observed were: 1. The electrons were emitted immediately - no time lag! 2. Increasing the intensity of the light increased the number of photoelectrons, but not their maximum kinetic energy! 3. Red light will not cause the ejection of electrons, no matter what the intensity! 4. A weak violet light will eject only a few electrons, but their maximum kinetic energies are greater than those for intense light of longer wavelengths!
35. Is the Electron a Particle?
36. The golfer tries to hit the blue-color tainted golf balls through the slits, where those who get through make two imprint lines. This golfer graphic reminds us of the reality we are all experiencing, but golf ball interference patterns are unthinkable.
37. Or is the Electron a Wave?
38. This is the multiple Feynman paths for just one particle from the particle gun to the screen. The explanation requires the particle to pass through all possible paths and thus on the way interfere with itself after passing through the two slits. Even though just one particle is fired at a time, we see interference patterns on the screen. However, we do not see the paths of the particles as in the drawing, but they represent the summation explanation for the particle’s passage through the two slits.
39. Initially appears random Still appears random Diffraction pattern emerges More hits at the measuring device Wave/Particle duality demonstrated
40. This is NOT what happens with the INDIVIDUAL particle being fired separately through the two slits.
41. The actual wave interference pattern remains right up to moment the electron detector is turned on, that is while the electron can still pass through two slits. This is where we sneakily place an electron detector just after the slit to see if we can catch the passage of the particle through either of the two slits.
42. Individual particles are once again detected with no interference pattern. This is what we actually see at the moment that the electron detector is switched on at either of the two slits.
43. Schematic diagram showing a Delayed-Choice Experiment. Source S emits a single electron in direction of two slit apparatus. On passing slits, electron is either absorbed by emulsion E if it is up. If emulsion is down, electron continues on to detection in either telescope T1 or telescope T2 which are focused on slits. Operator decides position of emulsion after electron has passed through slit system.
44. Schematic diagram of possible transactions in a Delayed Choice Experiment. (a) Electron is detected at emulsion E. (b) Electron is detected by particle detector T1. (c) Electron is detected by particle detector T2.
45. COSMIC THOUGHT EXPERIMENT calls for measuring individual photons from a quasar whose image has been split in two by a galaxy acting as a "gravitational lens." In a sense, the way the experiment is carried out now determines whether each photon -billions of years ago - acted like a particle, going one way or the other around the galaxy and ending up in one of the two detectors (a and b),or like a wave, going both ways around the galaxy and generating an interference pattern (c).
46. Matter Waves http://www.youtube.com/watch?v=DfPeprQ7oGc
47. De Broglie Proposes the Wave Nature of Matter to explain the structure of the atom c. 1922
48. Bohr Atom c. 1913
49. 2 p Electron Orbit
50. Electron Cloud
51. Electron Shells
52. But what the @$!& is an Electron Cloud?
53. A probability wave?
54. The electron cloud indicates the probability of finding the electron in a particular place around the nucleus. The electron seems to be a diffuse cloud or wave which becomes a particle only when we try to find it. Whenever we try to grab it, we never grab wave, we always grab particle.
55. THE MEASUREMENT PROBLEM
56. SCHRODINGER EQUATIONS Here H is the Hamiltonian for the system. As is a constant ket (it is the state ket at t = 0 ), we see that the time evolution operator obeys the Schrodinger equation: i.e. If the Hamiltonian is independent of time, the solution to the above equation is: Where we have also used the fact that at t = 0,U(t) must reduce to the identity operator. Therefore we get: Note that is an arbitrary ket. However, if the initial ket is an eigenstate of the Hamiltonian, with eigenvalue a , we get: Thus we see that the eigenstates of the Hamiltonian are stationary states, they only pick up an overall phase factor as they evolve with time. If the Hamiltonian is dependent on time, but the Hamiltonians at different time commute then, the time evolution operator can be written as: The alternative to the Schrödinger picture is to switch to a rotating reference frame, which is itself being rotated by the propagator. Since the undulatory rotation is now being assumed by the reference frame itself, an undisturbed state function appears to be truly static. This is the Heisenberg picture. The Time Evolution Operator Definition The time evolution operator U(t,t0) is defined as: That is, this operator when acting on the state ket at t0 gives the state ketat a later time t. For bras, we have: Properties Property 1 The time evolution operator must be unitary. This is because we demand that the norm of the state ket must not change with time, I.e: Therefore Property 2 Clearly U(t0,t0) = I, the Identity operator. As: Property 3 Also time evolution from t0 to t may be viewed as time evolution from t0 to an intermediate time t1 and from t1 to thfinal time therefore: U(t,t0) = U(t,t1)U(t1,t0)Differential Equation for Time Evolution OperatorWe drop the t0 index in the time evolution operator with the convention that t0 = 0 and write it as U(t) . The Schrodinger equation can be written as:
57. Schrödinger's cat - Materialist DualismA reductio ad absurdum: where does the wave function collapse into “reality”
58. Dr Who - Blink http://youtu.be/GFKa9tQqzrs
59. EPR - Einstein, Podolsy, Rosen: Is Quantum Theory Complete - Hidden Variables vs Non-Locality
60. Bell’s Coincidence Analyzer
61. The REALISTprediction (solid curve) for quantum correlation in an optical Bell test. The quantum-mechanical prediction is the dotted curve.
62. In the world of the very small, where particle and wave aspects of reality are equally significant, things do not behave in any way that we can understand from our experience of the everyday world. It isn’t just that Bohr’s atom with its electron “orbits” is a false picture, all pictures are false, and there is no physical analogy we can make to understand what goes on inside atoms. Atoms behave like atoms, nothing else. Sir Arthur Eddington summed up the situation brilliantly in his book The Nature of the Physical World, published in 1929. “No familiar conceptions can be woven around the electron,” he said, and our best description of the atom boils down to “something unknown is doing we don’t know what.” He notes that this “does not sound a particularly illuminating theory. I have read something like it elsewhere; The slithy toves Did gyre and gimbal in the wabe” … as Eddington pointed out more than fifty years ago, all the fundamentals of physics could be translated into “Jabberwocky”.There would be no loss of meaning, and conceivably a great benefit if we broke the instinctive association in our minds of atoms with hard spheres and electrons with tiny particles. John Gribbin
63. A curious feature of the Copenhagen interpretation is that it considers both the atom and the measuring device to be incomprehensible. We cannot understand the quantum world because its nature is utterly alien to human thought; we cannot explain the classical world because quantum theory - the physicists only basis for explaining anything today - simply takes the existence of the classical world for granted. In Furry’s words, the classical world is “logically prior” to the quantum theory and “is not expected to find an explanation in it.” Quantum theory predicts how a classical measuring instrument will respond to a quantum system, but the theory itself does not contain such measuring devices - nothing in there but proxy waves. Fortunately for the practice of physics, each of us is born into a world already inhabited by these inexplicable measuring devices: your eye is one example. In other words, the Old Physics attempted to explain macroscopic objects in terms of the atoms which make them up; the New Physics explains atoms in terms of macroscopic objects. In this inverted Copenhagen scheme, there is a sense in which atoms are made of measuring instruments and not the other way around. One of the main facts of life is that we radically change whatever we observe. Legendary King Midas never knew the feel of silk or a human hand after everything he touched turned to gold. Humans are stuck in a familiar Midas-like predicament: we can’t directly experience the true texture of reality because everything we touch turns to matter. Nick Herbert
64. We have reached a very interesting position. Ever since the beginning of modern science four or five hundred years ago, scientific thought seems to have moved man and consciousness further from the centre of things. More and more of the universe has become explicable in mechanical, objective terms, and even human beings are becoming understood scientifically by biologists and behavioural scientists. Now we find that physics, previously considered the most objective of all sciences, is reinventing the need for the human soul and putting it right at the centre of our understanding of the universe! Alternatively, others have suggested that the world is observed, not only by ourselves, but by another eternal conscious being, whom we might as well call ‘God’. The idea that God has a role in ensuring the continual existence of objects that are not being observed by human beings is actually quite an old one and led to the following nineteenth-century limerick: There once was a man who said, God Must think it exceedingly odd If he finds that this tree Continues to be When there’s no one about in the Quad Dear Sir, your astonishment’s odd I am always about in the Quad And that’s why the tree Will continue to be Since observed by, yours faithfully, God Alastair Rae
65. Anyone who is not shocked by quantum theory has not understood it. Neils Bohr. I have thought a hundred times more about the quantum problem as I have about general relativity theory. Albert Einstein. God does not play dice with the universe. Albert Einstein. I cannot seriously believe in quantum theory because … physics should represent a reality in time and space, free from spooky actions at a distance. Albert Einstein. I think that a particle must have a separate reality independent of the measurements. That is, an electron has spin, location and so forth even when it is not being measured. I like to think that the moon is there even if I am not looking at it. Albert Einstein. The world is one substance. As satisfying as this discovery may be to philosophers, it is profoundly disturbing to physicists as long as they do not understand the nature of that substance. For if quantumstuff is all there is and you don’t understand quantumstuff, your ignorance is complete. Nick Herbert.
66. Descartes founded the image of the human mind as a sort of nebulous substance that exists independently of the body. Much later, in the 1930s, Gilbert Ryle derided this dualism in a pithy reference to the mind part as “the ghost in the machine”. Ryle articulated his criticism during the triumphal phase of materialism and mechanism. The machine he referred to was the human body and the human brain, themselves just parts of the larger cosmic machine. But already, when he coined that pithy expression, the new physics was at work, undermining the world view on which Ryle’s philosophy was based. Today, on the brink of the twenty-first century, we can see Ryle was right to dismiss the notion of the ghost in the machine - not because there is no ghost, but because there is no machine. Paul Davies & John Gribbin
67. Reading List Alastair Rae, Quantum Physics: Illusion or Reality. 1986. CUP Nick Herbert, Quantum Reality: Beyond the New Physics. 1985. Anchor. John Gribbin, In Search of Schrodinger’s Cat. 1984. Corgi. Rosenblum & Kuttner, Quantum Enigma: Physics Encounters Consciousness. 2006. OUP. A.S. Eddington, The Nature of the Physical World. Kessinger Publishing. Reprint Paul Davies, God and the New Physics. 1988. Penguin. Paul Davies & John Gribbin, The Matter Myth. 1992. Penguin.