Two series of monographs on logic are now available (for free) on Project Euclid: Perspectives on Logic. Lecture Notes on Logic. I think several of the monographs are well-known in their areas, such as Model Theory of Fields.

CMU students conduct a mock protest at the G20. Slogans include “Safer Data Mining” and “MapReduce, MapReuse, MapRecycle: Green Data Processing”.

The Bohr-Einstein debates, now in convenient puppet form.

For those nattering nabobs of negativity among you who insist that correlation does not equal causation, I give the ultimate counterexample: clear and incontrovertible proof that the decline in US oil production has led to a decline in the quality of...

If you’re interested in learning about recursion theory and the Godel incompleteness theorem, these lecture notes by Jeremy Avigad are terrific. In this approach, incompleteness follows from properties of algorithms, which I think is the clearest...