I've been writing a lot on free will lately. One argument has been this set of definitions:
Random: caused by nothing
Determined: caused by a prior event
Free: caused by a substance
I am convinced, for the moment, that this set of definitions can save free will from incoherence. The definitions didn't originate with me, so they will be old news to people more erudite than I am, but they are new to me and I am impressed by them. The definition of free that I am using succeeds in making free will neither random nor determined without falling into mysticism, which I had previously thought was impossible. Further, it removes some of the mysteriousness associated with agent causation by specifying which part of the agent is responsible for the free act.