…ed one within the other. He was able to exploit this structural feature in order to produce an algorithm that solves the cube in a maximum of 52 moves. Thistlethaite’s approach is the kind of solution that one’s inner-mathematician would really like to see: a solution that actually teaches us something about the structure of the Rubik’s cube. Rokicki’s brute-force combinatorics approach offers little in this regard, despite its practical effective…
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…Broaden your horizons in the new year with everyone’s favorite philosophy of science database. Here are some tricks to ease the experience. Get Started Reading Books and Articles on the Cheap. Trying to save money this year? Stop paying so much to read! Get Started Learning General Relativity Online. Free general relativity — what more could you ask for in 2009? Get Started Improving Your Philosophical Apparel. Get a new look for the new year. Her…
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…f spatial regions. However, William and the astronaut will agree about the order in which time-like separated events occur: first Harold is crowned, and then Harold is slain. Figure 1: An observer on Earth and an astronaut traveling away with velocity c/2 will describe two different foliations of spacetime into space-like hypersurfaces of simultaneity. On the other hand, an accelerating observer will not generally agree about the order in which th…
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…cribe this situation is to say that, once a now has been specified, we are guaranteed a definite future and a definite past. These categories never get mixed up: the past cannot arrive after now; the future cannot arrive before now. There is some real regularity that guarantees future, present, and past will be delivered to us in the right order. The regularity underlying our experience of passage reflects the same reality as the regularity underl…
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…than $200. Nevertheless, let it be known that an electronic copy of this book does is circulating on the inter-tubes. If you look around a bit, you’ll likely be able to find and download a copy for free. Just throwing that out there. See also my advice about reading on the cheap, and about learning GR online. This list was inspired by a recent post over at It’s Only a Theory — further suggestions are more than welcome. Happy reading! (*) Added Fe…
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