The experience of freewill

A staple argument for libertarian freewill is the argument from experience. However, Brand Blanshard contends that introspection undermines the empirical argument for libertarian freewill. In that sense, reflective experience undercuts the prereflective impression of freewill:

The first reason is that when we are making a choice our faces are always turned toward the future, toward the consequences that one act or the other will bring us, never toward the past with its possible sources of constraint. Hence these sources are not noticed. Hence we remain unaware that we are under constraint at all. Hence we feel free from such constraint. The case is almost as simple as that. When you consider buying a new typewriter your thought is fixed on the pleasure and advantage you would gain from it, or the drain it would make on your budget. You are not delving into the causes that led to your taking pleasure in the prospect of owning a typewriter or to your having a complex about expenditure. You are too much preoccupied with the ends to which the choice would be a means to give any attention to the causes of which your choice may be an effect. But that is no reason for thinking that if you did preoccupy yourself with these causes you would not find them at work. You may remember that Sir Francis Galton was so much impressed with this possibility that for some time he kept account in a notebook of the occasions on which he made important choices with a full measure of this feeling of freedom; then shortly after each choice he turned his eye backward in search of constraints that might have been acting on him stealthily. He found it so easy to bring such constraining factors to light that he surrendered to the determinist view (p21).

http://www.archive.org/stream/determinismfreed01c2newy/determinismfreed01c2newy_djvu.txt