X-Message-Number: 11643 From: Date: Fri, 30 Apr 1999 00:31:40 EDT Subject: Understanding quantum mechanics Personal philosophy--life's decisions--and "natural philosophy" (science) are closely tied, although few perceive this clearly. A key element of contemporary science is quantum mechanics. I have said previously that one needs to read at least several top-level writers (in addition to some introductory textbooks) to begin to get a feeling for it. To the books I listed before, let me add a couple more: THE LIFE OF THE COSMOS, Lee Smolin, Oxford, 1997; QUANTUM CONCEPTS IN SPACE AND TIME, ed. Penrose and Isham, Oxford, 1986; THE ELEGANT UNIVERSE, Greene, Norton, 1999. One of the clearest conclusions is that, after a whole century (if we start with Planck), NOBODY has figured out what it means, and disagreements if anything are widening, not narrowing. Einstein: "All these fifty years of conscious brooding have brought me no nearer to the answer to the question, 'What are light quanta?' Nowadays every Tom, Dick and Harry thinks he knows it, but he is mistaken." Feynman: "...it appears peculiar and mysterious to everyone--both to the novice and to the experienced physicist." Abner Shimony (in QUANTUM CONCEPTS, above): "...the [many worlds interpretation] is an immense extrapolation of the linear dynamics of quantum mechanics...We are so far from having evidence for the validity of this dynamics for macroscopic systems...and for the space-time field that the extrapolation....should be recognized as sheer conjecture." (Incidentally, Shimony also said the same thing about many worlds that I did in terms of desirability from our point of view: It makes reality of all the possible good things, but also of all the possible bad things.) Bart Kosko {parphrased]: "Quantum mechanics must be wrong because its equations are linear, and reality is never linear." Lee Smolin [paraphrased]: "The laws and constants of nature may vary as universes evolve. Space and time may not exist except as apparent relationships between events." Brian Greene: "Centuries from now, superstring theory...may have developed so far beyond our current formulation that it might be unrecognizable even to today's leading researchers." Most working physicists tend to shrug off questions of interpretation--mainly, no doubt, because they have enough to do with their own immediate bread-and-butter problems. They also remind us of the many successes and the lack of failures in the predictions of the quantum mechanical formalism. But all this work, as far as I know, relates only to extremely simple systems. Remember that Q.M. is postulated to apply to ALL phenomena and to all bodies--not just electrons but also atoms; not just atoms but also molecules; not just molecules but also people and planets and galaxies. You can calculate the "wave length" or the "frequency" of the earth--but you can't conduct a verifying diffraction experiment. Finally, while I remember it, a word about "dimensions" as discussed in string theory and in general relativity. All those great men abused the language and confused generations of students. Time is not a "dimension" except in a certain mathematical formalism; time and space are profoundly different. The "coiled dimensions" of string theory are nothing of the sort; they are coiled curves or surfaces or physical objects. A path or a hyperpath or a physical object can be coiled, but a "dimension" cannot. To clarify this slightly, think about a circle. It is a one-dimensional figure in the sense that only one coordinate--either an angle or a displacement along the circumference--is required to specify a location on the circle. But to measure the curvature you need to relate the linear displacement to the central angle (more curvature if the circumference is smaller), and of course the curvature takes place in a second dimension. It makes no more sense to speak of "curved spacetime" or of "coiled dimensions" than it would to speak of a circle as a "curved straight line." Of course I recognize that people do indeed use fractured language successfully, by separating what they do from what they say, but it hinders understanding and progress. Robert Ettinger Cryonics Institute Immortalist Society http://www.cryonics.org Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=11643