Shifting Paradigms in Population Studies

There's a terrific post over at Dienekes' blog in which he systematically traces the changing consensus view on European origins over the course of the past century. An invasion [arrows on the map] model was replaced by a cultural diffusion model, which was supplanted by a demic diffusion model, which was replaced by a paleolithic persistence model, and now today we have come full circle to the current position.

What does seem certain... is that dramatic events took place starting at the Neolithic, and that modern Europeans trace their ancestry principally to Neolithic and post-Neolithic migrants, and not to the post-glacial foragers who inhabited the continent.

which is essentially to restate the old multiple invasions [arrows on a map] understanding. It's been a long strange journey that has brought us back to where we started, and it's not over yet.

Read it here.

What this points out is the way in which "science" operates as one consensual view is replaced time and again by another and yet another. In other words, scientific consensus is constantly changing and scientific authority is a foundation of shifting sands. Only a fool would build a public policy structure on it.