Group Structural Realism (Part 4)

…in the tower, or the ‘whole shebang.’ This introduces a tower’s worth of ‘lower down’ groups into our ontology, and risks the possibility that a ‘highest’ automorphism group doesn’t exist. Or, if it is possible to fix a structural foundation by promoting the ‘whole shebang’ of higher group structures, then it seems that our ontology is excessively extravagant and uninformative. In summary: structural realism is forced to either risk incoherence (…

Read more

Happy 2009! Five Tutorials for Philosophers of Physics

…torials for philosophers of physics — and anyone else who cares — from the soulphysics archives. Get Started Using Automatic Symbol Insertion in MS Word. Reduce the stress this year. Here’s an easy way to use mathematical symbols without having to deal with LaTeX. Get Started Improving Your Philsci Archive Experience. Broaden your horizons in the new year with everyone’s favorite philosophy of science database. Here are some tricks to ease the exp…

Read more

Get Started Learning General Relativity Online

…to Differential Geometry and General Relativity, by Stefan Waner. A beautifully arranged collection of lecture notes on differential geometry. Approach is highly mathematical, taking the reader from basic point-set topology all the way to Einstein’s field equations. Tensors and Relativity, by Peter Dunsby. A first course in general relativity, beginning with special relativity. Includes an “assignments” section with hints. The layout is ugly and…

Read more

Fundamental Rubik’s Cube Problem Is Nearly Solved

…y 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, allowed him to clip through 16 million positions per second, and gave him the 25 move upper bound. This algorithm is based on a similar algorithm developed by Herbert Kociemba, and used in his fascinating Cube Explorer software (which you can download for free). However, to produce his most recent resul…

Read more

Elegant Desktop ToDo List

…y a TXT file on your Desktop: Create a new Shell geeklet in the Geektool preference pane Enter the command: cat PathToYourList/YourList.txt To synchronize multiple computers, make sure the file is in a Dropbox folder. Quicksilver. This is why I own a mac. It’s free from Blacktree.com. If you’re new to it, try this beginner’s guide. To set up the ‘Append’ and ‘Completed’ functions seen in the screencast: On the Quicksilver > Plugins page, add the ‘…

Read more