WHEN Joseph Conlon was an undergraduate in the early 2000s, he avoided popular science accounts of string theory because he wanted to engage with it on a technical level, without preconceptions. It was a few years after the “second string theory revolution”, when theoretical physicists felt they might be about to crack open the deepest workings of reality, perhaps even deliver a theory of everything. As he explored the maths, Conlon was captivated.
String theory famously suggests that everything is made up of one-dimensional strings (see “String theory: A primer”, below), and also predicts a huge array of possible universes – some 10500, for those taking notes. Whatever you think about that, it is fair to say that string theory hasn’t generated the testable predictions that many were hoping for. Today, it has a reputation for being untestable, maybe even unscientific. One arch string theory critic dubbed it “not even wrong”.
But for Conlon, now a physicist at the University of Oxford, the thrill never faded. String theory remains a potential route to uniting the incompatible ways we think about gravity and the quantum world, he argues, to create a unified theory of quantum gravity. He also claims that his field has been unfairly maligned, and that its detractors are applying double standards. He even insists that string theory does make predictions that we could conceivably probe with upcoming astronomical observations.
Here, Conlon tells New Scientist about the enduring joys of string theory, why it is too early to write it off, and why we…