One hundred and fifty years ago, the Russian chemist Dmitri Mendeleyev placed 63 chemical elements into a meaningful order, from the lightest to the heaviest. Has this periodic table revealed the natural order of the elements, or is it more of a model of our thinking? If the latter, does the table itself therefore create order? Executive Director Jürgen Renn explores this question in this article in Deutschlandfunk Kultur on the work of Mendeleyev and Lothar Meyer.