'A River Runs Through it': How the discourse metaphor crossing the Rubicon structured the debate about human embryonic stem cells in Germany and (not) the UK

In 2001 the metaphor of ‘crossing the Rubicon’ and many variations on this theme ran through the German debate about research using human embryonic stem cells. This article studies how the Rubicon metaphor was argumentatively exploited after having been prominently used by President Rau in a speech Wird alles gut? – Für einen Fortschritt nach menschlichem Maß (Will everything turn out well? For progress befitting humanity). From then on, it was adapted and changed by various participants to support or reject arguments for or against the use of embryonic stem cells in biomedical research. Compared to Germany, the Rubicon metaphor had much less of a ‘life’ in the UK and this article will try to show why that should have been the case. The contextual analysis of the Rubicon metaphor continues research into the discursive and cultural aspects of metaphors, by describing how a metaphor emerged as part of a political/social/rhetorical process, how it resonated within society and culture (or not), how it was evaluated in discourse and how it was creatively reformulated, extended and transformed by various actors engaged in political arguments. Studying the diverse meanings that emerged from the use of the Rubicon metaphor in Germany contributes to the study of discourse metaphors but also to the semasiology of metaphors, especially their polysemy, variability and flexibility.