Physics has become obsessed with strings, branes and multiple dimensions, yet the big questions remain fundamentally unanswered. Has the time come to admit these wild conjectures have failed, and move on?
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Fundamental physics now finds itself in a historically unprecedented situation. The multi-decade dominance of string theory, along with its extremely speculative research into the implications of exotic scenarios far removed from any hope of testability, has changed the subject in dramatic and fundamental ways.

What used to be considered part of the dubious fringes of science has now become institutionalised within the mainstream. In physicist Lee Smolin’s recent book, The Trouble With Physics, he characterises the current sociology of the field as dominated by ‘groupthink’, with too few physicists willing to admit how far off the tracks things have gone. The nearly infinite complexity of string theory, M-theory, branes, higher dimensions and the multiverse has led to a vast number of possible challenging calculations for people to do to keep themselves busy, all embedded in a mathematical structure far too poorly understood to ever lead to definitive, falsifiable predictions.

The problems of the Standard Model that faced my colleague and I a quarter of a century ago continue to inspire new generations of young theorists to devote their lives to work that might some day lead to real progress. But these problems remain extremely difficult ones, and we have little in the way of promising ideas, with far too much effort going into the evasion of difficulties and the pursuit of the chimera of unification through ever more complex higher dimensional constructions inspired by string theory.