Although the burden of proof in the framework of sufficiency of disclosure as a rule lies with the party raising the objection, this principle does not apply to cases where the application as filed does not provide a single example or other technical information from which it is plausible that the claimed invention can be carried out, e.g. see T 1329/11.
Furthermore, if there are serious doubts as regards the possibility of performing the invention and repeating it as described, the burden of proof as regards this possibility, or at least a demonstration that success is credible, rests with the applicant or the proprietor of the patent. In opposition, this may be the case where, for example, experiments carried out by the opponent suggest that the subject-matter of the patent does not achieve the desired technical result. As regards the possibility of performing and repeating the invention, see also F‑III, 3.