This 15 minute video,
Why Free Will Doesn’t Exist, was posted to me by an atheist I have been posting to on another forum. I do not agree with him that we do not have free will. Below is the gist of his argument. The first two paragraphs below are a summary of what is in the video and the last paragraph is this atheist’s personal opinion.
What makes free will an illusion is that the choice you make will always be either the choice to do what you most want to do (even when it overrides your wanting to do something else) or the choice you don't want to make but are forced to make.
We like to think that we have free will, that we could make choices other than the ones we make. However, free will -- the ability to have acted differently -- is an illusion. No matter what choice you ever made, you never really had the ability to have chosen differently.
Since free will is an illusion, it's also nothing but a lame excuse for certain problems that theists run into, for example, why a good god would allow evil to exist.