Quod non est in actis, non est in mundo. What is not in the files is not in the world. In German the maxim reads Was nicht in den Akten ist, ist nicht in der Welt. It comes from written court procedure, in which nothing could be considered that was not in the court files. Berlin’s administration puts the same idea in a handbook for its officials. They must keep files and darin ihr Handeln vollständig, nachvollziehbar und transparent dokumentieren, document their actions in them completely, traceably and transparently. In 2017 the legal journalist Martin Rath called the maxim eine billige Weisheit, a cheap wisdom. He also wrote that the file is a Mittel der Vernunft, an instrument of reason.