If the researchers argue that "convergent evolution" leads to biological complexity, they do present a theoretical model to explain the origins of complexity. And I submit that this approach is fundamentally sound since it interprets whatever evidence is presented within a framework that is scientifically-justifiable since it does not ask that we retreat to mathematical probability, but rather to actually use the observed dynamics of biological systems as a guide when interpreting the evidence of observed phenomena.
Good point. In that case, even if they did have to present a theoretical basis on which all that nifty complexity could have emerged, they have in fact done so to the degree reasonably required by their own work.
So what do we call it when electric power grid engineers use genetic programming (evolutionary algorithms) to converge on the best solutions for power distribution? The key requirement of these programs is that they have to solve very complex problems quickly.