time delay

How to explain the fact that our conscious decision to move our arm happens quite a long time after the brain decides to move it? We have known this since the 1970s. I think this is central to the mind-body problem. Most people assume that consciousness is thus an after-effect, body english, or an illusion. Or they argue that the timing works out to give us the illusion of autonomy. I think we need to flip everything over. Maybe the illusion of autonomy and the fact that consciousness happens after the brain decides to move the arm are what enables the brain to make a better, slower, more complex decision, without turning us into klutzes or Hamlets.