The examinations, however, in the higher branches of knowledge should, I conceive, be entirely voluntary. It would be giving too dangerous a power to governments, were they allowed to exclude anyone from professions, even from the profession of teacher, for alleged deficiency of qualifications: and I think, with Wilhelm von Humboldt, that degrees, or other public certificates of scientific or professional acquirements, should be given to all who present themselves for examination, and stand the test; but that such certificates should confer no advantage over competitors, other than the weight which may be attached to their testimony by public opinion.