"FREE WILL" REDUX

   Free will is an illusion.  There is an elegant discussion of this illusion in Tolstoy's War and Peace.  Consider: free will is an experience.  Can we trust experience?  Consider: experience tells us that the earth does not move.  But we know it is moving in many different ways and directions at enormous speeds.  So we cannot trust our individual experience.  How do we know about all of the earth's various movements?  We know about them through the collective experience of scientists over many generations.  So experience counts but not individual experience.

The Tolstoy Fallacy: That experience and feeling are trustworthy modes of interrogating and knowing reality.
As in the question of astronomy then, so in the question of history now, the whole difference of opinion is based on the recognition or nonrecognition of something absolute, serving as the measure of visible phenomena. In astronomy it was the immovability of the earth, in history it is the independence of personality- free will.
As with astronomy the difficulty of recognizing the motion of the earth lay in abandoning the immediate sensation of the earth's fixity and of the motion of the planets, so in history the difficulty of recognizing the subjection of personality to the laws of space, time, and cause lies in renouncing the direct feeling of the independence of one's own personality. But as in astronomy the new view said: "It is true that we do not feel the movement of the earth, but by admitting its immobility we arrive at absurdity, while by admitting its motion (which we do not feel) we arrive at laws," so also in history the new view says: "It is true that we are not conscious of our dependence, but by admitting our free will we arrive at absurdity, while by admitting our dependence on the external world, on time, and on cause, we arrive at laws."
In the first case it was necessary to renounce the consciousness of an unreal immobility in space and to recognize a motion we did not feel; in the present case it is similarly necessary to renounce a freedom that does not exist, and to recognize a dependence of which we are not conscious. Leo Tolstoy, Chapter XII of War and Peace. I suggest you read this.

Our behavior is generated at the intersection of the flow of consciousness and the flow of affordances (encountered opportunities in the world around us).  Free will gains some traction from the fact that we are complex open systems and open systems are lawful but not determined.  The greater and more complex the flow of affordances the stronger the sense that we have free will.