What do science advisors have to offer in conflict situations? Can evidence and expertise ever cut through political polarisation and contribute to finding new forms of compromise? What kinds of advisors do we need, and what kinds of advice? Should they be strictly neutral, or is plurality and openness more useful? Do politicians really want scientific evidence, and what if it puts pressure on their longstanding political positions? Our guest today, Marc Sanjaume i Calvet, is an expert on the Catalan-Spanish independence debate as well as democracy, federalism and secession more generally. The president of Catalonia appointed him as the coordinator of an expert group working towards a so-called 'clarity agreement' for the Catalan region.