If we believe the whole of our consciousness is just the sum of our desires and behaviors and react accordingly to the internal and external stimuli of the world our ego then we only have the illusion of free will. Ie if you know some one who has a “temper or “short fuse” and you know what to say to set the person of or lose control they are acting in a pre determined way. However someone who chooses how to respond to something because they have recognized that the only thing that is in our control is ourselves is now acting freely or exercising there free will. This is why all world religions speak about start by looking within in order to understand our true nature and work on gaining mastery over ourselves. There was a phrase at the entrance of the Temple of Delphi which read, "Homo Nosce Te Ipsum," which means, "Man, know yourself, and you will know the universe, and its gods."

Finally nature at least in the view of these philosophers does not have awareness and thus has no ability of free will and must act in a predetermined way.. At least this is how I would interpret what these philosophers at trying to say at this point in my own journey.