In all honesty I really don’t think it makes a huge difference whether there is determinism or free will – in terms of how we will live our lives that is. I say this because if free will is an illusion, it is an illusion we will continue to have regardless of the scientific facts. We will continue to live our lives as if we are ‘free’ regardless of what laws govern it. Take gravity for example. Gravity exists, and there is nothing we can do about it, but we have learned to live with gravity (in the sense that we know how it operates, so we don’t do things like jump off buildings, or build our houses on thin poles). Gravity exists yet we often live our life ignorant of it. I am not conscious of gravity all the time. When I fall down the stairs I don’t think “damn, gravity is to blame!” When I see a chair I don’t think “gravity is keeping that chair in place”.
Basically we live our lives with gravity but never acknowledge it – to us it exists but at the same time we are very much unaware of it. It is such a common phenomenon in our lives that we are largely indifferent to it on a mental level. Likewise, if determinism is proven then it really makes no difference. We will continue to live our lives with determinism but we will be largely ignorant of it. To us, we will always free, or at least in control of our actions. And even if determinism is proven, I am more than positive we will continue to live as if it weren’t a major part our lives.