This is a subject I nearly started a thread about a while back. And apologies, I've not read all the thread so might be repeating a bit. I find it difficult to understand that we have free will since I can't imagine where it comes from. OK, I know that's no argument but I also think no one has come up with any explanation how it arose.
My thinking goes like this. RNA/DNA came about by inevitable chemical reactions. It began to copy - by inevitable chemical reactions - and evolution set in. The reactions became more complex, and therefore the cells became more complex. Eventually we get multicellularity and nerve cells. Still all inevitable chemical reactions?? Then we get an animal that can make choices, for example to fight or flee a situation. Is this still the result of a highly complex set of inevitable chemical reactions? Without an explanation of how thoughts or consciousness work, don't we have to think that? If not, when did it change and how? Even assuming the existence of consciousness, surely it must have a purely chemical basis. So it's just a bit of an illusion really.
I think this kind of thinking is what some of the posts from a few days ago where alluding to.
This depends on what you think free will is. If you think it must be some soul that can interfere with the (practically) causal universe, then of course it does not exist. However, if you think the 'soul' is nothing else then the functioning brain, you have another problem. Saying you are your brain implies that you cannot say that you are forced by your brain in acting in certain ways: something cannot force itself. So whatever free will is, you are not forced to do anything by your brain processes.
You must realise that actions are higher order phenomena. And the same holds for inevitability. Say, you throw a stone perfectly to a rock: then in a certain sense, it is inevitable that you will hit the rock. But try the same with a cat: it can run away, and so it is 'evitable' for the cat to be hit. Everything in evolution is about reducing inevitability: move to places where is more light, more food, or (top of the top), avoid to sit in a cold house by ordering burning oil timely (anticipation of the future). It is in these higher orders that you must look for a correct concept of free will: namely the ability to act according to your wishes and beliefs (hopefully justified true beliefs, i.e. knowledge). In this sense we surely have free will.
I just had a glance at your website: it is interesting that you name your newest blog entry 'Our Unique Responsibility'. What is responsibility without free will?