…ience more pleasant. Use Google to search philsci archive. Google is a far superior search engine. Why use anything else? Enter your search keywords into Google, followed by this string: site:philsci-archive.pitt.edu This will return a Google search for your keywords, restricted to Philsci archive. Trust me, this is a real pain-reliever: for example, searching for “van fraassen” returns baloney on Philsci archive’s search engine, while Google retu…
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…positions on a Rubik’s cube — that’s 40 with 19 zeros after it. So even a super-computer that can check a trillion cube positions a second (which doesn’t exist) would require a length of time equal to the current age of the Universe in order to check every position. The plan of attack is thus to vastly reduce the number of cube positions to be checked, and then apply a very efficient algorithm. Rokicki’s algorithm, together with 8 GB of memory, a…
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…heorem or something like it? It is widely believe that the CPT may fail in generic extensions of quantum theory. In particular, the requirement of a unitary representation of the Poincaré group is pretty strong, and may not hold in the kind of general context of interest in quantum gravity. Just search for CPT-violation on the arxiv to see what I mean. But there is a sense in which something “like” a CPT theorem probably will hold in physics beyon…
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…the Weyl Curvature Hypothesis (wikipedia). This hypothesis is true at the border between aeons in Penrose’s Conformal-Cyclic-Cosmology — indeed, this is apparently required in order to glue the aeons together smoothly. A remaining question, of course, is whether or not this is related in any useful way to the Boltzmann entropy on the scale of every-day objects… Second: the black-hole information paradox. As I’ve ranted before: black hole evaporati…
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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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