### The failure of string theory?

My holiday reading is a fascinating book by Peter Woit entitled "Not Even Wrong" which argues that string theory has failed. There was quite a backlash from certain outspoken string theorists, but no-one appears to have rebutted Woit's specific criticisms.

The gist of the book's argument is that string theory isn't really a theory at all as it makes no experimentally falsifiable predictions and it doesn't yet have an underlying mathematical foundation. It's really a highly fashionable piece of wishful thinking about where the next fundamental theory of physics might come from. I can think of other fashion industries closer to home, but that's a topic for the future.

I think the crucial question is how long a speculative search for a new physical theory should continue before it makes a prediction that can be checked experimentally. Perhaps string theory will ultimately deliver something useful, but, in the interim, other directions are effectively being starved of resources.

The book mentions in passing that the Massachusetts Institute of Technology (MIT) is now publishing its courses online under an initiative known as "Open Course Ware". If you want an easy example of a computing course, take a look at the lecture notes on module dependence diagrams, given by the Department of Electrical Engineering and Computer Science.

I've been investigating a mathematical model of software modules recently and some of the dependency relations look like they would benefit from a bit of graph theory, so I was delighted to find some mathematics course notes and even a link to a softcopy graduate textbook on graph theory via the MIT site.

Unfortunately, the graduate course notes are handwritten and then scanned in, so would need more effort to explore. However, since I'm a novice at graph theory, I was pleased to find some undergraduate material nicely captured in PDF files.