I recently finished a book on string theory written by Lee Smolin. For those who are a little hazy about it, string theory is a conjecture that the fundamental physical entities are minute string-like units of energy. These strings vibrate, form themselves into loops and generally behave in ways that supposedly account for the physical universe and all its properties. Unfortunately it hasn’t quite worked out like that.
Lee Smolin is an interesting guy, because he is a physicist who gave string theory a try before moving on to other things such as loop quantum gravity. He didn’t make a career out of string theory as many physicists have done and in his book he tells us why.
Smolin thinks string theory has proved to be a dead-end with no predictive capacity and no physical evidence that the theory has any advantage over alternatives. He tells this story of failure in a good-natured and entirely understanding way, which is only remarkable when you consider what a powerful grip string theory has had over physicists during the past thirty odd years.
If you are interested in this kind of thing, give the book a try. It provides a powerful and sobering example of how scientific communities may become so inward-looking, so committed to their theorising, that they fail to connect their conjectures and speculations with observable reality. Fascinating and colourful scientific conjectures are a gift to science journalists, but is this the way we want our science to go?