Here’s some interesting Sunday reading: Frank Close wrote a very nice article for Prospect Magazine on the business of testing scientific theories in Physics. Ideas about multiverses and also string theory are the main subjects under consideration. I recommend it. My own thoughts on the matter? Well, I think most of you know them. Here are three key points:- (1) Many important ideas in physics started out as purely mathematical digressions inspired by physics… You can’t find those ideas and make them work without exploring where they lead for a while, perhaps long before you even know how to test them. So we need that component of physics research as much as we need some of the other aspects, like designing and performing new experiments, etc. (2) You never know where a good idea will ultimately find its applications… It is often not where we think it might be initially. (3) Of course, testability (confronting an idea with experiment/observation) is key to the enterprise of doing science, there is no doubt in my mind. I do not think we need to start considering whether testability is something we can abandon or not. That’s clearly silly. We just need to be careful about rushing in to declare something testable or not testable before it has had a chance to develop into something useful. Unfortunately, everyone has a different take on just when it is time to make that declaration… and that’s what causes all the shouting and political arguments that generate a lot of heat and precious little light.