"At President to me you appeared to say that you do not definitively know whether free will exists or not. However, most of us assume it exists in our every day interactions; therefore, in a sense whether it actually exists or not is irrelevant. Have I got this correct? If so, this is what I described as a social construct."
Mostly. I was responding along a relatively narrow tangent to SYnapse's comment. I certainly experience freewill, and feel no need to prove it to myself; and others will assume I have it anyway. So SYnapse's questions about whether it can be "proven" miss the point, I think.
For a more comprehensive idea of how I view it, my original post (first itt!) should suffice.
"It is my view then that those who rely on a solely materialistic view of the world, belief in free will is a matter of faith. A faith ultimately rooted in an awareness of the ethical vacuum that must follow from the absence of free will."
I would agree with the first sentence but not the second. It's a matter of faith in the same sense that believing your senses function as you perceive them to function is a matter of faith: a proposition you ultimately cannot prove but without which you cannot function. Without freewill, and the requisite assumption that you direct your own actions and make your own decisions, you just don't exist in any meaningful sense. Though ethical concerns are important, I think even they're secondary to the existential concern at play here. Why even worry about whether a given action is right or wrong if you can only but observe that action taking place? Your input cannot influence the reaction to that action if you don't have freewill. Worrying about the ethical implications of not having freewill requires a presupposition of freewill to be meaningful, because if you didn't have freewill, you couldn't act on your conclusions from those implications anyway.
My perception of which is more important might be skewed, though, because ethics as a whole just doesn't interest me or register as something I care about.