The most interesting thing about the efficient markets hypothesis is not whether it is valid or not – clearly it is not – but how it has managed to remain so influential for so long. At a recent conference in London on the subject, organised by the CFA Institute, Professor Andrew Lo of Massachusetts Institute of Technology offered the audience a simple explanation: “physics envy”.

This was a reference back to the early inspiration of the Nobel economics laureate Paul Samuelson, who set out to find for economics a set of fundamental laws that would do for the dismal science what Newton’s laws of dynamics had done for physics, and from which a rigorous general theory with practical uses could subsequently be developed.