I liked this short essay in Nature by Martin Heisenberg on free will (HT). Heisenberg is a neurobiologist (and the son of Werner), and his perspective is shaped by the work he’s done on more primitive organisms – in the essay he talks about bacteria and also the fruit flies (the famous drosophilia) which have been the subject of his own work. In short, the combination of microscopic randomness (ultimately sourced from the quantum realm) and an adaptive self-directedness (primitive intentionality -- see also here) comprise freedom.
In the human case, the discussion is obscured by the focus on the will found via introspective self-consciousness and its relation to our actions. But introspection is an extreme latecomer in evolution. Heisenberg suggests we have a kind of real freedom, shared with many other organisms, irrespective of whether our introspective picture is accurate or flawed. He says: “I maintain that we need not be conscious of our decision-making to be free. What matters is that our actions are self-generated…Why should an action become free from one moment to the next simply because we reflect upon it?”