”We hear what we know” - On the power of conceptsand how traditional fiddle music in contemporary society can benefit fromfolk music theorySwedish fiddle music, just as many other fiddle traditions, has a strong connection to dance. Making people want to move their feet is one of the chief tasks ofthe fiddler, and this connection still influences the music today, even thoughthe music might be played on concert stages or be digitally streamed.So what constitutes this knowledge of the fiddler? What is important when playing a certain local styleof Swedish polska so people actually can dance to it?    If you live in an isolated community with no contact with the outside world you might not have to reflect on what is the stylistic features of your tradition but today folk music generally lives in a multi-stylistic world where different value systemsthat originates from other music traditions than fiddle music dominates. Today’s fiddlers will have to relate to today’s world of music, whether we want it or not.In Sweden, since the 19th century, there has been a tradition of mystifying the knowledge of the fiddler, making the competence of playing a matter of socio-cultural background,  geography and ancestry.The perils of this view is that the qualities of  art of fiddling might be obscuredand  actually might be lost when music transforms - as music always do.In this talk Sven Ahlbäck, who is a traditional fiddler deeply rooted in traditional Swedish FolkMusic and very involved in development of new ensemble playing and teaching, will talkabout how conceptualising stylistic qualities of Swedish fiddle music such as e.g.asymmetrical beats, swing, bowing and intonation have influenced the developmentof today’s Swedish folk music, even beyond the fiddle.