Knocking on Heaven's Door

by: Lisa Randall, read in 2011

7 "...the reason we cannot determine whether new dimensions exist, or what their role would be even if they did, as that they are too small or too warped for us to be able to detect."
8 "Extra dimensions of space might exist, but they would have to be tiny or warped or otherwise currently hidden from view in order for us to explain why they have not yet yielded any noticeable evidence of their existence." I suggest that an explanation for why they are hidden from view is that our 4D space-time continuum may be an embedded manifold in higher dimensional space-time and the geometric properties of embedded manifolds precludes any observation outside the manifold. As for "noticeable evidence", I suggest that the well-established curvature of space-time strongly suggests additional dimensions in which the curvature takes place.
16 "For any given problem, we use what we call an effective theory. The effective theory concentrates on the particles and forces that have "effects" at the distance in question." This should be extended to include dimension as well as distance.

To paraphrase her next sentence and following paragraph, "Rather than delineating particles and interactions in terms of unmeasurable parameters that describe more fundamental behavior, we [might] formulate our theories, equations, and observations in terms of the things that are actually relevant to the [extra dimensions] we might detect.

"The effective theory we apply at [four space-time dimensions needn't] go into the details of an underlying physical theory that applies to [extra dimensions]. It only asks about things you could hope to measure or see. If something is beyond the [manifold in which we reside and] are working, you don't need its detailed structure. This practice is not scientific fraud. It is a way of disregarding the clutter of superfluous information. It is an "effective" way to obtain accurate answers efficiently and keep track of what is in your system."

50 "Even allowing for a God or some spiritual force that might have exerted influence earlier on as a prime mover, it is inconceivable from a scientific perspective that God could continue to intervene without introducing some material trace."
55 "The problem is that in order to subscribe both to science and to a God—or any external spirit—which controls the universe or human activity, one has to address the question of at what point does the deity intervene and how does He do it." True.
55 "According to the materialist, mechanistic point of view of science, if genes that influence our behavior are a result of random mutations that allowed a species to evolve, God can be responsible for our behavior only if He physically intervened by producing that apparently random mutation." First, that leaves all non-genetic influences on behavior not addressed. Second, influences on random behavior would be undetectable by science if they occurred below a reasonable threshold. God may load the dice.
55 "Is God manipulating electrical processes in our brains? Is He pushing us to act in a certain way or creating a thunderstorm for any particular individual so he or she can't get to their destination? On a larger level, if God gives purpose to the universe, how does He apply His will?" No; not via thunderstorms. But the car/driver model works to explain how God's will works via human will. The amplification of willful influences, beginning with random quantum events below the detectable threshold and propagating up through mechanisms suggested by Hameroff and Penrose and analogous to automobile control linkages and mechanisms can explain the mind/body influences, and how He applies His will.
56 "The problem is that not only does much of this seem silly, but that these questions seem to have no sensible answer that is consistent with science as we understand it. How could this "God magic" possibly work?" Labels like 'silly' and 'magic' don't address my previous proposal. What's 'silly'? or 'magic' about the linkage from accelerator pedal to carburetor?
56 "Clearly people who want to believe that God can intervene to help them or alter the world at some point have to invoke nonscientific thinking." This is probably true for a majority of non-scientific thinkers.
56 "A religious or spiritual belief that involves an invisible undetectable force that nonetheless influences human actions and behavior or that of the world itself produces a situation in which a believer has no choice but to have faith and abandon logic—or simply not care." Not true. Such "invisible and [previously] undetectable force[s]" influence the behavior of a Mars rover, yet JPL scientists have faith that the control signals will indeed influence the rover. They do not abandon logic and they care a great deal.
56 "This incompatibility strikes me as a critical logical impasse in methods and understanding. Stephen Jay Gould's purportedly "nonoverlapping magisteria"—those of science, covering the empirical universe, and religion, extending into moral inquiry—do overlap and face this intractable paradox too." It is not intractable if we consider the car/driver model, which can get us past the impasse.
56 "...once we talk about substance and activity—be it in and of the brain or in reference to celestial objects—we are in the domain of science." True. But if we extend the domain of science, not just at the fringes of scale, but also into the possibility of large extra dimensions and of the possibility of deliberate influence on the outcomes of putative random quantum events, science may be able to address the "hard" questions.
57 "I didn't get how someone trained as a biologist could not believe in evolution." Here's how: by "believing" or suspecting that the theory of evolution is an incomplete explanation.
57 "Empirically based logic-derived science and the revelatory nature of faith are entirely different methods for trying to arrive at truth." True. But a third way is logical deduction from alternative hypotheses.
57 "But although God might have a way of avoiding the logical contradictions, science does not." The "contradiction" is a result of the strawman of a "magical" or "revelatory" religion. There is no contradiction if you simply deduce from different hypotheses.
59 "We [scientists] are confident only in what we can verify through experiments or in what we can deduce from experimentally confirmed hypotheses." Not true. Many scientists are confident that consciousness resides in the brain, that there is no data link between brain and something outside the brain, that evolution explains all aspects of life, that large extra dimensions don't exist, none of which has been experimentally verified or deduced from experimentally confirmed hypotheses. And think about the recent scientists who were confident that continents didn't drift, that ulcers were not caused by bacterial infection, and even today, there are scientists who are confident that human activity causes global warming.
62 This section is an unconvincing attempt to categorize people into a false dichotomy of science vs. religion. Too many vague generalizations and political innuendos.
78 "Not seeing or even having a mental image doesn't mean that we can't deduce the physical elements or processes that are happening at these [small] scales." The same should be true for large extra dimensions.
87 "Even if it seems that we will have a tough time developing technology to explore much smaller scales, we can still try to deduce structure and interactions at those distances through theoretical and mathematical arguments." The same approach should work for large extra dimensions.
168 Global warming
177 Check out this link:
180-1 Global warming
192 "People interested only in the bottom line rally against regulation while those who are interested in safety and predictability argue for it." She overlooks the most important interest of all, that is the products desired by hundreds of millions of consumers.
178-198 The political innuendo in this chapter diminishes the book.
197 Is there a connection between Lubos Motl and Tom Banks? If so, what?
211 "Uncertainty enters only at the level of less than one in a trillion and makes the magnetic moment of the electron the constant of nature with the most accurate agreement between theoretical prediction and measurement."
211 "As explained in Chapter 1, new phenomena whose effects appear only at different energy scales or when we make even more precise measurements can underlie what we see. Because we haven't yet experimentally studied those regimes of distance and energy, we don't yet know." She seems to ignore, or discount, the possibility of real effects in large extra dimensions which do not result in 4D phenomena that we can measure. Some of these may be deducible from mathematics.
212 "The Standard Model therefore leaves room for new discoveries, and new physical theories can yield deviations, but they must be small enough to have eluded detection up to now." Small size is not the only logically possible way to avoid detection; residing in higher dimensions and outside our 4D manifold would also make effects undetectable.
212 "Current experiments are based on the understanding that new ideas build upon a successful effective theory that applies at lower energies. Their goal is to unveil new matter or interactions, keeping in mind that physics builds up knowledge scale by scale." Entirely new possibilities might present themselves if we consider ideas based on the existence of large extra dimensions.
242 The Standard Model chart.
254 The Standard Model diagram
277 "Why isn't everything whizzing around at the speed of light, which is what matter would do if it had zero mass?"
294 "...scalars...are particles with zero spin..."
312 "Clearly, since we don't see them, these new dimensions of space must be hidden." True. But we don't see any of the usual four dimensions either.
313 "The idea is that as much that is hidden from view at our limited resolution, the dimensions might be to [sic] small to discern." I can't parse this sentence.
313 "...we might not notice a curled-up dimension that we cannot travel through—much as a tightrope walker would view his path as one-dimensional, whereas a tiny ant on the wire might experience two, as illustrated in Figure 61." This analogy fails for higher dimensions. There is no analog for the tightrope walker who would have to be a 4D spatial being. Now who could that be?? In the analogy, we are the ants, to whom the extra dimension is "visible".
313 "Theodor Kaluza extended Einstein's ideas to suggest the existence of a fourth spatial dimension, and, five years later, Oskar Klein suggested how it might differ from the familiar three." IMHO Kaluza's good idea was contaminated and ruined by Klein's suggestion which threw physicists off the track and they have not yet recovered and gotten back on track.
315 "...the [branes] that will be of most interest for models addressing the hierarchy problem involve those that extend over three dimensions—the three physical dimensions of space that we know." This is a good start. The next step is to consider that the extra dimensions are nearly flat, astronomically large, and that we should not expect to be able to "see" or detect higher dimensional structures with our 3D bodies and instruments. Follow Kaluza's lead.
316 "They can have consequences for phenomena we are now trying to understand, and if so, we might see evidence in the imminent future." This may be even more true than Randall realizes.
319 "For this idea to work, the extra dimensions have to be enormous compared to what theoretical considerations lead us to expect." What "theoretical considerations"? If it is that extra dimensions must be "small" and "curled-up", then these considerations can be abandoned.
320 "The problem is that these very large dimensions would expand along with the rest of the universe until the temperatures are very low." An unsubstantiated claim. We can inflate a balloon (a 2D manifold) in 3-space without any of the three spatial dimensions "expanding".
321 "That poses a difficult challenge for scenarios with such large additional dimensions." What challenge? Consider the balloon analogy.
325 "We don't see the other universe on the other brane because the lone shared force is gravity, and gravity is too weak in our vicinity to communicate readily observable signals." An unconvincing explanation. Most of our observations are carried by EM force, not gravity. All observable interactions involving EM force are confined to our manifold, or brane, simply because they are part of the manifold. To detect gravity in the other brane our instruments would have to "point" or align in a direction normal to our brane, which is physically impossible.
337 "Discovering how and why nature hides string theory's extra dimensions would be a stunning achievement. Physicists want to figure out how this occurs." I suggest examining the mathematical properties of embedded manifolds. I think the "how and why" will be obvious.
408 "...I started thinking about extra dimensions of space in the 1990s" I started thinking about extra dimensions in the 1950s and first wrote my thoughts about them in 1987.
411 "We can't be sure what the scales that demarcate true paradigm shifts in the future will be..." It may not be demarcated by length scale at all, but possibly by additional spatial or temporal dimensions.
415 "In the past, our nation's attention to science and technology—along with the recognition that we need to make long-term commitments and stick to them—has proved to be a successful strategy that kept us in the forefront of new developments and ideas. We now seem to be in danger of losing these values that have worked so well for us in the past." Why no mention of SSC in this context?? Or at all in the book??

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