Are Viroids Molecular Fossils of the RNA World?

We discuss a difficulty that may be raised against the Diener hypothesis that viroids may be interpreted as molecular fossils of the RNA world. We provide a possible way of removing such a difficulty (hence supporting the Diener hypothesis). Our reasoning entails further work by plant pathologists on a proposed search for a well-defined molecular process. It is shown that such process would be of biological and evolutionary significance.